10.5826/dpc.1302a115
Introduction:  Seborrheic keratosis (SK), lichen planus-like keratosis (LPLK), and solar lentigo (SL) are common benign skin lesions. These lesions are frequently seen adjacent to each other or can arise from one another. They can sometimes be difficult to differentiate despite having distinct histopathological features.  
Objectives: We evaluated dermoscopic images of 80 skin lesions to confirm the term ‘benign keratosis’ is useful for an undifferentiated SK/LPLK/SL where there are overlapping clinical and dermoscopic characteristics.
Methods: Clinical and dermoscopic images were sourced from a teledermoscopy service database of 13,000 lesions in 7,000 patients. The database was queried for SK, SL or LPLK in sun-exposed sites. Each lesion was evaluated based on specific dermoscopic criteria and the results analyzed.
Results:  Lesions were identified with mixed clinical and dermoscopic criteria of SK and SL, and in some, dermoscopic criteria for LPLK were also present.
Conclusions: This study highlights the relationship between these lesions. We confirm the term ‘benign keratosis’ is useful for mixed lesions or for those that are difficult to classify. 
text/xml
2160-9381
2096
en
Amanda Oakley
https://creativecommons.org/licenses/by-nc/4.0
Dermatology Practical & Conceptual
dermoscopy
Benign Keratosis: A Useful Term?
Text.Serial.Journal
https://dpcj.org/index.php/dpc
Original Article
2023-04-29
2021-10-09
2023-04-29
2023-05-31
e2023115
Dermatol Pract Concept
Introduction:  Seborrheic keratosis (SK), lichen planus-like keratosis (LPLK), and solar lentigo (SL) are common benign skin lesions. These lesions are frequently seen adjacent to each other or can arise from one another. They can sometimes be difficult to differentiate despite having distinct histopathological features.  
Objectives: We evaluated dermoscopic images of 80 skin lesions to confirm the term ‘benign keratosis’ is useful for an undifferentiated SK/LPLK/SL where there are overlapping clinical and dermoscopic characteristics.
Methods: Clinical and dermoscopic images were sourced from a teledermoscopy service database of 13,000 lesions in 7,000 patients. The database was queried for SK, SL or LPLK in sun-exposed sites. Each lesion was evaluated based on specific dermoscopic criteria and the results analyzed.
Results:  Lesions were identified with mixed clinical and dermoscopic criteria of SK and SL, and in some, dermoscopic criteria for LPLK were also present.
Conclusions: This study highlights the relationship between these lesions. We confirm the term ‘benign keratosis’ is useful for mixed lesions or for those that are difficult to classify. 
Amanda Oakley
2023/04/29
10.5826/dpc.1302a115
e2023115
Department of Dermatology, Waikato Hospital, Hamilton, New Zealand
2160-9381
dermoscopy
en
e2023115
Lim D, Oakley AM, Rademaker M. Better, sooner, more convenient: a successful teledermoscopy service. Australas J Dermatol. 2012;53(1):22-25. DOI:10.1111/j.1440-0960.2011.00836.x. PMID: 22309326.
Benign Keratosis: A Useful Term?
https://dpcj.org/index.php/dpc/article/download/2096/2108
                          Benign Keratosis: A Useful Term?
                                            Rebecca Scott1, Amanda Oakley2,3


1 University of Aberdeen, Waikato Hospital, Hamilton, New Zealand
2 Waikato District Health Board, Hamilton, New Zealand
3 University of Auckland, Faculty of Medical and Health Science Medical School, Waikato Campus, Auckland, New Zealand



Key words: benign keratosis, seborrhoeic keratosis, lichen planus-like keratosis, solar lentigo, dermoscopy
Citation: Scott R, Oakley A. Benign Keratosis: A Useful Term? Dermatol Pract Concept. 2023;13(2):e2023115. DOI: https://doi
.org/10.5826/dpc.1302a115
Accepted: November 9, 2022; Published: April 2023
Copyright: ©2023 Scott et al. This is an open-access article distributed under the terms of the Creative Commons Attribution-
NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use,
distribution, and reproduction in any medium, provided the original authors and source are credited.
Funding: None.
Competing Interests: None.
Authorship: All authors have contributed significantly to this publication.
Corresponding Author: Amanda Oakley, Waikato District Health Board, Pembroke Street, 183 Pembroke Street,
Hamilton, New Zealand 3204. University of Auckland, Faculty of Medical and Health Science Medical School, Waikato Campus.
Email: amanda.oakley@waikatodhb.health.nz; Amanda.oakley@me.com




  ABSTRACT             Introduction: Seborrheic keratosis (SK), lichen planus-like keratosis (LPLK), and solar lentigo (SL) are
                       common benign skin lesions. These lesions are frequently seen adjacent to each other or can arise from one
                       another. They can sometimes be difficult to differentiate despite having distinct histopathological features.
                       Objectives: We evaluated dermoscopic images of 80 skin lesions to confirm the term ‘benign kerato-
                       sis’ is useful for an undifferentiated SK/LPLK/SL where there are overlapping clinical and dermoscopic
                       characteristics.
                       Methods: Clinical and dermoscopic images were sourced from a teledermoscopy service database of
                       13,000 lesions in 7,000 patients. The database was queried for SK, SL or LPLK in sun-exposed sites.
                       Each lesion was evaluated based on specific dermoscopic criteria and the results analyzed.
                       Results: Lesions were identified with mixed clinical and dermoscopic criteria of SK and SL, and in
                       some, dermoscopic criteria for LPLK were also present.
                       Conclusions: This study highlights the relationship between these lesions. We confirm the term ­‘benign
                       keratosis’ is useful for mixed lesions or for those that are difficult to classify.




                                                                         keratosis), can be difficult to differentiate although each has
Introduction
                                                                         defined clinical and dermoscopic characteristics [1]. The his-
Seborrheic keratosis (SK), solar lentigo (SL) and lichen                 topathological features of SK, LPLK and SL differ but as they
planus-like keratosis (LPLK, also known as lichenoid                     are benign, only those suspicious of melanoma are subjected


Original Article | Dermatol Pract Concept. 2023;13(2):e2023115                                                                         1
to biopsy. An SK can arise from an SL and an LPLK can arise         hypergranulosis and focal acanthosis. Eosinophils and
from an SL or from an SK. There is limited research linking         plasma cells with Civatte bodies are also noted [15].
these three lesions [2].                                               A link between SL and SK was supported by histolog-
     The International Skin Imaging collaboration (ISIC) aims       ical evidence of transformation in 50 cases, and histolog-
to improve early melanoma detection [3]. ISIC has hosted            ical SL was documented at the periphery of 50 specimens
challenges since 2016 covering lesion segmentation, detec-          of LPLK [16]. Biopsies taken from a solitary lesion 5 years
tion of clinical diagnostic patterns, and lesion classification     apart reported the evolution of a SL into a solitary LPLK
with the purpose of developing computer-based image anal-           [17]. In a series of 100 cases of LPLK evaluated by histol-
ysis tools. The 2019 ISIC challenge classified pigmented le-        ogy, 28% had an adjacent skin lesion, most commonly SK
sions into 9 diagnostic categories including ‘benign keratosis’     (8.4%), SL (7%) and actinic keratosis (5.6%) [18]. A fur-
(seborrheic keratosis, solar lentigo, and lichen planus-like        ther clinicopathologic review of LPLK cases confirmed the
keratosis) [4]. The ISIC public-access archive includes more        most frequently seen adjacent lesions were SL (73%) and SK
than one thousand dermoscopic images classified as ‘benign          (6.5%) [2]. Gene mutations (FGFR3 and PIK3CA) have been
pigmented keratosis’ [5].                                           identified in SL and SK to support a link between them [14].
     However, the term ‘benign keratosis’ is not well known
by dermatologists. The classification of these entities by clin-
ical terminology tools is inconsistent.                             Objectives
                                                                    The main objective of the study was to confirm the term
• ICD-11 (version 09/2020) lists all three entities within the
                                                                    ‘benign keratosis’ is useful, by comparing the clinical and
    benign squamous cell neoplasm category (seborrheic ker-
                                                                    dermoscopic features of typical SK,SL, LPLK and lesions in
    atosis XH0949, solar lentigo XHB58, lichen planus-like
                                                                    which overlapping features were present.
    keratosis XH63L8), and includes a separate entry for be-
    nign keratosis, NOS (XH0S03).
• ICD-11 also lists seborrheic keratosis and lichen                 Methods
    planus-like keratosis within benign keratinocytic acan-
    thoma (2F21) and solar lentigo within photoaging of the         Clinical and dermoscopic images were sourced from a teleder-

    skin (EJ20) [6].                                                moscopy service database of 13,000 lesions in 7,000 patients

• The SNOMED International SNOMED CT browser (31                    [19]. The database was queried for SK, SL or LPLK in sun-­

    January 2021 edition) does not link seborrheic keratosis        exposed sites (scalp, ears, face) (Table 1). Non-randomized

    (disorder code SCTID: 394726009) and solar lentigo (disor-      lesions were selected that had good quality clinical images

    der code SCTID: 72100002), and lichenoid keratosis is clas-     typical for SK (N=20), SL (N=20), LPLK (N=20) or having

    sified as lichenoid actinic keratosis (SCTID: 403198004) [7].   mixed clinical features (N=20), ie SK+SL+/-LPLK), matched
                                                                    for anatomical area and camera (3Gen DermLiteCam V1).
     SK is a common benign epidermal age-related prolifer-          Lesions identified as clinically ‘benign’ were not formally

ation of keratinocytes [8]. SK can occur anywhere on the            excised, therefore histopathological findings were not avail-

body sparing the mucous membranes, palms and soles. There           able. Each lesion was evaluated using specific dermoscopic

are several histological subtypes which often overlap; they         criteria for SK, SL, and LPLK (1) (Table 2).

are characterized by acanthosis, papillomatosis, hyperkera-
tosis and the presence of pseudocysts [9].                          Results
     SL is a macular hyperpigmented lesion linked to chronic
sun exposure. Typical histological features are acanthosis          The 80 lesions evaluated were associated with 440 mac-
with elongated epidermal ridges with accompanying actinic           roscopic, polarized and nonpolarized dermoscopic images
elastosis [10].                                                     (Table 3).
     LPLK, also known as lichenoid keratosis, is thought
to represent an inflammatory regressive response to a               Dermoscopic Criteria of Seborrheic
pre-existing cutaneous lesion. The pathogenesis is not com-         Keratosis (Table 4)
pletely understood, however most literature suggests LPLK           Analysis of SKs revealed that:
is a regressive form of benign epithelial neoplasm such as
an SK or SL [11-13]. LPLK lesions can be seen in multiple           • SKs exhibited an average of 3.3 SK criteria.
regressive stages and therefore can often be confused with          • Three or more of the five SK criteria were present in
other skin tumors including basal cell carcinoma and mela-            17/20 SKs.
noma [14]. Histological features are lichenoid lymphocytic          • ‘Sharply demarcated border’ and ‘lines curved and thick
infiltrate, hyperkeratosis with focal parakeratosis, variable         (cerebriform)’ were each present in 19/20 SKs.

2                                                                       Original Article | Dermatol Pract Concept. 2023;13(2):e2023115
                             Table 1. Original database collection with patient demographics.




Table 2. Dermoscopic criteria for seborrheic keratosis, solar lentigo, and lichen planus-like keratosis.
       Seborrheic Keratosis                           Solar Lentigo                           Lichen planus-like Keratosis
 • Sharply demarcated border             •   Sharply demarcated                       • Fine scale
 • Dots or clods white clustered         •   Scalloped border                         • Polymorphous vessels
   or disseminated                       •   Homogenous brown pigmentation            • Dotted vessels
 • Clods brown-yellow or orange          •   Homogenous and structureless             • Gray dots
   (rarely black)                            pigmentation                             • Diffuse gray dotted pattern
 • Lines curved and thick                •   Faint reticulation                       • Color (white, pink, red, orange, purple,
 • Lines brown curved parallel           •   Fine parallel lines                        blue-gray, black, light brown, dark brown)
   thin                                  •   Fine parallel lines                      • Color red excluded
                                         •   Ink spot lentigo excluded


          Table 3. Average number of dermoscopic criteria present in SK/SL/LPLK lesion group.
         Lesion type                          SK Criteria                       SL Criteria                    LPLK Criteria
 SK                                          3.3/5 (66%)                       1.8/6 (31%)                      0.0/5 (0%)
 SL                                          2.0/5 (40%)                       5.3/6 (88%)                      1.0/5 (2%)
 LPLK                                        0.6/5 (12%)                       2.4/6 (34%)                      1.8/5 (35%)
 Mixed                                       3.75/5 (75%)                      4.4/6 (73%)                      0.6/5 (12%)

LPLK = Lichen-planus like keratosis; SK = Seborrheic keratosis; SL = Solar lentigo.


• ‘Clods brown-yellow or orange (rarely black)’ were pres-                  SK criteria were less common in SLs with the exception
  ent in 16/20 SKs.                                                     of ‘Sharply demarcated border’ seen in 18/20, a shared char-
• ‘Dots or clods white clustered or disseminated’ and                   acteristic of SL lesions. ‘Lines curved and thick (cerebriform)’
  ‘lines brown curved parallel thin’ were present in                    and ‘Lines brown curved parallel thin’ were seen in 8/20 and
  6/20 SKs.                                                             10/20 SL lesions consecutively.

Original Article | Dermatol Pract Concept. 2023;13(2):e2023115                                                                        3
       Table 4. Dermoscopic criteria for seborrheic keratosis in various clinically diagnosed lesions.
                       Sharply               Dots or clods                Clods brown,              Lines curved         Lines brown
      Lesion         demarcated            white clustered or           yellow or orange              and thick         curved parallel
       Type            border               disseminated                  (rarely black)            (cerebriform)            thin
 SK                  19/20 (95%)                6/20 (30%)                 16/20 (80%)                19/20 (95%)         6/20 (30%)
 SL                  18/20 (90%)                2/20 (10%)                  2/20 (10%)                 8/20 (40%)        10/20 (50%)
 LPLK                 6/20 (30%)                0/20 (0%)                   2/20 (10%)                 4/20 (20%)         0/20 (0%)
 Mixed               19/20 (95%)               11/20 (55%)                 17/20 (85%)                16/20 (80%)        12/20 (60%)

LPLK = Lichen-planus like keratosis; SK = Seborrheic keratosis; SL = Solar lentigo.


               Table 5. Dermoscopic criteria for solar lentigo in various clinically diagnosed lesions.
                                                                                           Faint
                     Sharply          Homogenous                                      reticulation
    Lesion         demarcated            brown               Structureless             (criss-cross        Scalloped        Fine lines
     Type            border           pigmentation              (~10%)                  network)            border          parallels
 SK                19/20 (95%)          2/20 (10%)             0/20 (0%)               4/20 (20%)          7/20 (35%)       4/20 (20%)
 SL                18/20 (90%)         17/20 (85%)           16/20 (80%)              20/20 (100%)        20/20 (100%)     13/20 (65%)
 LPLK                6/20 (30%)         0/20 (0%)            18/20 (90%)               9/20 (45%)         14/20 (70%)       0/20 (0%)
 Mixed             19/20 (95%)          0/20 (0%)            17/20 (85%)              16/20 (80%)         19/20 (95%)      15/20 (75%)

LPLK = Lichen-planus like keratosis; SK = Seborrheic keratosis; SL = Solar lentigo.



     SK features were present to a lesser degree in LPLK                    SL criteria were less common in the SK group except for
­lesions. A ‘Sharply demarcated border’ was present in 6/20             ‘sharply demarcated border’, which was present in 19/20 SL
LPLKs, ‘Lines curved and thick (cerebriform)’ in 4/20 and               lesions. ‘Faint reticulation’ and ‘scalloped border’ were seen
‘Clods brown-yellow or orange (rarely black) were present               in 4/20 and 7/20 SK lesions consecutively.
in 2/20. No LPLKs had ‘dots or clods white clustered or dis-                Certain SL criteria were high in LPLK lesions. ‘Struc-
seminated’ or ‘lines brown curved parallel thin’.                       tureless (amalgamate of homogenous and structureless pig-
     All 5 SK criteria were present in 6/20 of the mixed le-            mentation)’ was present in in 18/20 and ‘scalloped border’
sions; 19/20 had a ‘sharply demarcated border’ and ‘dots or             in 14/20 LPLK lesions. ‘Homogenous brown pigmentation’
clods white clustered or disseminated’, ‘clods brown-yellow             and ‘fine lines parallel’ were present in none of the LPLKs.
or orange (rarely black)’ and ‘lines brown curved parallel                  All mixed lesions had three or more SL criteria. None had
thin’ were commonly seen.                                               ‘homogenous brown pigmentation’. ‘Scalloped border’ was
                                                                        present in 19/20 and ‘structureless’ in 17/20 of mixed lesions.
• The mixed lesion group had an average of 75% SK criteria.
• The SL and LPLK groups had an average of 40% and                      • The mixed lesion group had an average of 73% SL criteria.
    12% SK criteria respectively.                                       • The SL and LPLK groups had an average of 88% and
                                                                           34% SL criteria respectively.
Dermoscopic Criteria of Solar Lentigo (Table 5)
Analysis of SLs revealed that:                                          Dermoscopic Criteria of Lichen Planus-Like
                                                                        Keratosis (Table 6)
• SLs exhibited an average of 5.28 SL criteria.
• Four or more of the SL criteria were present in 19/20 SL              • LPLKs exhibited an average of 1.75 LPLK criteria:
    lesions.                                                            • ‘Diffuse gray dotted pattern’ was present in all 20 LPLK
• ‘Faint reticulation’ and ‘scalloped border’ were each pres-              lesions.
    ent in all 20 SL lesions.                                           • ‘Gray dots’ were present in 10/20 LPLK lesions.
• ‘Homogenous brown pigmentation’ was present in 17/20                  • There were no ‘polymorphous vessels’ in LPLK lesions
    SL lesions.                                                            and ‘fine scale’ was present in only 1/20 LPLK lesions.
• ‘Structureless (amalgamate homogenous and structureless
    pigmentation)’ was present in 16/20 lesions and ‘fine lines         No LPLK criteria were present in SK lesions. SL findings
    parallel’ was present in 14/20 lesions.                             were less common also with 3 out of the 5 criteria having



4                                                                            Original Article | Dermatol Pract Concept. 2023;13(2):e2023115
 Table 6. Dermoscopic criteria for lichen planus-like keratosis in various clinically diagnosed lesions.
                                            Polymorphous                 Dotted vessels                                  Diffuse gray
  Lesion Type          Fine scale               vessels                 (small red dots)            Gray dots           dotted pattern
 SK                   0/20 (0%)               0/20 (0%)                    0/20 (0%)                0/20 (0%)              0/20 (0%)
 SL                   0/20 (0%)               0/20 (0%)                    0/20 (0%)                1/20 (5%)              1/20 (5%)
 LPLK                 1/20 (5%)               2/20 (10%)                   2/20 (10%)             10/20 (50%)            20/20 (100%)
 Mixed                3/20 (15%)              0/20 (0%)                    0/20 (0%)                4/20 (20%)             4/20 (20%)

LPLK = Lichen-planus like keratosis; SK = Seborrheic keratosis; SL = Solar lentigo.




Figure 1. Mixed Lesion displaying appearance of SK arising from SL. Lesion ID 15040477. Dermoscopy features —sharply demarcated
border, dots or clods white clustered or disseminated, clods brown yellow or orange (rarely black), Lines curved and thick (cerebriform), lines
brown curved parallel thin, faint reticulation (criss-cross network), scalloped border, fine lines parallels.




Figure 2. Seborrhoeic Keratosis classical lesion. Lesion ID 35110201. Dermoscopy features — sharply demarcated border, dots or clods
white clustered or disseminated, clods brown-yellow or orange (rarely black), lines curved and thick (cerebriform), lines brown curved
parallel thin.




Figure 3. Solar Lentigo classical lesion. Lesion ID 44740194. Dermoscopy features — sharply demarcated border, homogenous brown pig-
mentation, structureless (approx. 10%), faint reticulation (criss-cross network), scalloped border, fine lines parallel.



Original Article | Dermatol Pract Concept. 2023;13(2):e2023115                                                                               5
Figure 4. Lichen Planus-like Keratosis classical lesion. Lesion ID 46600410. Dermoscopy features — structureless (approx. 10%), faint
reticulation (criss-cross network), scalloped border, grey dots, diffuse grey dotted pattern.




a 0/20 result. ‘Gray dots’ and ‘Diffuse gray dotted pattern’        lowest positive result for SK criteria had a thick scale reduc-
were present in no SL lesions.                                      ing dermoscopic feature detail.
    LPLK criteria were more common in the Mixed lesions                 The SL criterion ‘scalloped border’ was present in all 20
compared to classic SL and SK. ‘Diffuse gray dotted pattern’        SL and Mixed lesions. ‘Faint reticulation’ was seen in 16/20
and ‘Gray dots’ were seen in 4/20 Mixed lesions.                    Mixed lesions. LPLK lesions also displayed SL features. A
                                                                    high percentage of classic LPLK lesions displayed specific SL

Conclusions                                                         criteria including ‘Structureless’ (18/20), ‘Scalloped border’
                                                                    (14/20) and ‘faint reticulation (criss-cross network)’ (9/20).
Analysis of the lesions selected for this study confirms that       LPLK may arise from an SL with sections of the lesion rep-
the specific dermoscopic criteria suggested in dermoscopedia        resenting regressive structures of SL. ‘Faint reticulation’ and
for SK, SL and LPLK can be observed in the other clinically         ‘scalloped border’ were seen in all 20 SL lesions confirming
diagnosed lesions [1].                                              that these criteria have high specificity to SL. ‘Homogenous
    Our clinically selected SL and Mixed lesions displayed          brown pigmentation’ showed high specificity in SL lesions
the highest number of listed dermoscopic criteria followed          and was uncommonly observed in other lesion groups. This
by SK and LPLK lesions. We found that dermoscopic criteria          is a classical feature of an SL; the mixed lesions had a com-
for clinically typical SL and SK overlap. ‘Sharply demarcated       bination of features and therefore could not be classified as
border’ was found in 19/20 (95%) of SKs and 18/20 (90%)             ‘homogenous’.
of SLs. The SK features, ‘lines curved and thick (cerebri-              The key dermoscopic features in the LPLK Lesions were
form)’ and ‘lines brown curved parallel thin’ were commonly         ‘diffuse gray dotted pattern ‘in all 20 classic LPLK lesions
seen in SL. SL features of ‘faint reticulation’ and ‘scalloped      and ‘gray dots’ in 10/20. LPLK lesions are most easily clin-
border’ were found in otherwise typical SK.                         ically recognised in the late regressive stage as early phase
    ‘Sharply demarcated border’ was present in 19/20 of the         lesions are nonspecific. Only 2/20 LPLK lesions in our selec-
mixed group which correlates with these lesions being pre-          tive sample displayed ‘polymorphous vessels’ and ‘dot ves-
dominantly SL or SK. The mixed lesions displayed signifi-           sels’. ‘Fine scale’ was not displayed within any LPLK lesions
cant findings for both SK and SL criteria, and LPLK criteria        however was noted in 3/20 mixed lesions. Fine scale was
were less common. SK criteria had the highest result with an        difficult to detect on the clinical and dermoscopic images as
average of 3.4/5 (74%) of mixed lesions displaying SK crite-        a contact fluid had been applied. The largest color variation
ria. Three out of five SK criteria had higher overall findings      group seen in LPLK was ‘light brown/grey’ in 11/20 LPLK le-
in Mixed lesions than in the SK group. SL criteria were also        sions and reflects the classic regressive features in this sample
common with an average of 4.4/6 (73%) of Mixed lesions.             of LPLK lesions. ‘Light brown/dark brown were most com-
Mixed lesions chosen had less LPLK criteria at 0.6/5 (12%).         mon in the SK, SL and Mixed groups. Few LPLK features
    ‘Dots or clods white clustered or disseminated’ are typi-       were present in classic SL or SK lesions, however SK and
cal of SK but in our sample, this feature was present in 11/20      SL features were displayed in LPLK lesions. SL criteria were
Mixed lesions and in fewer SK lesions (6/20). It may be a           more common with an average of 2.4/6 (34%) features pres-
less common characteristic of SK or reflect the small sample        ent. SK features were also seen with ‘lines curved and thick
size. As expected, few LPLK lesions exhibited SK criteria. A        (cerebriform) seen in 4/20 lesions and the common SL/SK
‘sharply demarcated border’ was seen in 30% of LPLKs. We            feature of ‘sharply demarcated border’ seen in 6/20 lesions.
noted that 2/20 of the clinically typical SK lesions with the       This indicates overlap between these lesions.



6                                                                        Original Article | Dermatol Pract Concept. 2023;13(2):e2023115
    Mixed lesions displayed evidence of end-stage regressive             7. SNOMED International -Medical Terminology.Available from:.
LPLK features with the commonest features present being                     https://browser.ihtsdotools.org/. Accessed July 24, 2021
                                                                         8. Greco MJ, Bhutta BS. Seborrheic Keratosis. In: StatPearls. Trea-
‘Gray dots’ (4/20) and ‘Diffused gray dotted pattern’ (4/20).
                                                                            sure Island (FL): StatPearls Publishing. Available from https://
Other features were infrequent. Mixed lesions displayed a
                                                                            www.ncbi.nlm.nih.gov/books/NBK545285/. Accessed August 11,
high proportion of SL/SK criteria alongside these regressive                2021.
LPLK findings. This points to a relationship between the                 9. Hafner C, Vogt T. Seborrheic keratosis. J Dtsch Dermatol Ges.
evolution of these lesions as previously documented in the                  2008;6(8):664-677. DOI:10.1111/j.1610-0387.2008.06788.x.
literature.                                                                 PMID: 18801147
                                                                        10. Ortonne JP, Pandya AG, Lui H, Hexsel D. Treatment of solar
    Benign keratoses arise in most older people. Lesions
                                                                            lentigines. J Am Acad Dermatol. 2006;54(5 Suppl 2):S262-S271.
we had clinically diagnosed as SK had overlapping dermo-
                                                                            DOI:10.1016/j.jaad.2005.12.043. PMID: 16631967.
scopic criteria for SL, and others we diagnosed as SL had               11. Watanabe S, Sawada M, Dekio I, Ishizaki S, Fujibayashi M,
dermoscopic criteria for SK. We identified some lesions                     Tanaka M. Chronology of lichen planus-like keratosis features
with mixed clinical and dermoscopic criteria of SK and                      by dermoscopy: a summary of 17 cases. Dermatol Pract Concept.
SL, and in some, dermoscopic criteria for LPLK were also                    2016;6(2):29-35. DOI:10.5826/dpc.0602a06. PMID: 27222769.
                                                                            PMCID: PMC4866624.
present. This study highlights the relationship between
                                                                        12. Nagrani N, Jaimes N, Oliviero MC, Rabinovitz HS. Lichen
these lesions. We can confirm that the term ‘benign kera-
                                                                            planus-like keratosis: clinical applicability of in vivo reflectance
tosis’ would be useful for mixed lesions or for those that                  confocal microscopy for an indeterminate cutaneous lesion.
are difficult to classify. This would include lesions with                  Dermatol Pract Concept. 2018;8(3):180-183. DOI:10.5826
overlapping SL and SK features and those with features                      /dpc.0803a06. PMID: 30116660. PMCID: PMC6092072.
of intermediate or end-stage regressive LPLK features                   13. Bugatti L, Filosa G. Dermoscopy of lichen planus-like kerato-
                                                                              sis: a model of inflammatory regression. J Eur Acad Dermatol
wherein the features of origin are characteristic of a pri-
                                                                              Venereol. 2007;21(10):1392-1397. DOI:10.1111/j.1468-3083
mary SL or SK.
                                                                              .2007.02296.x. PMID: 17958847.
                                                                        14.   Liopyris K, Navarrete-Dechent C, Dusza SW, et al. Clinical and
References                                                                    dermoscopic features associated with lichen planus-like kera-
                                                                              toses that undergo skin biopsy: A single-center, observational
 1. Braun R, Nouveau S. Solar lentigines/ seborrhoeic keratoses/              study. Australas J Dermatol. 2019;60(2):e119-e126. DOI:10.1111
    lichen planus-like keratosis dermoscopedia. In ­Dermoscopedia.            /ajd.12955. PMID: 30450536. PMCID: PMC6520177.
    Available from: https://dermoscopedia.org/w/index.php?title         15.   Zaballos P, Blazquez S, Puig S, et al. Dermoscopic pattern of inter-
    =Solar_lentigines&oldid=16362. Accessed April 23, 2021.                   mediate stage in seborrhoeic keratosis regressing to lichenoid ker-
 2. Vincek V. Lichen planus-like keratosis: clinicopathological eval-         atosis: report of 24 cases. Br J Dermatol. 2007;157(2):266-272.
    uation of 1366 cases. Int J Dermatol. 2019;58(7):830-833.                 DOI:10.1111/j.1365-2133.2007.07963.x. PMID: 17553042.
    DOI:10.1111/ijd.14358. PMID: 30565224.                              16.   Mehregan AH. Lentigo senilis and its evolutions. J Invest Derma-
 3. International Skin Imaging Collaboration (ISIC) overview.                 tol. 1975;65(5):429-433. DOI:10.1111/1523-1747.ep12608175.
    Available from: https://www.isicarchive.com/#!/topWithHeader/­            PMID: 127813.
    tightContentTop/about/aboutIsicOverview. Accessed April 23,         17.   Goldenhersh MA, Barnhill RL, Rosenbaum HM, Stenn KS.
    2021.                                                                     Documented evolution of a solar lentigo into a solitary lichen
 4. International Skin Imaging Collaboration (ISIC) Archive, 2019             planus-like keratosis. J Cutan Pathol. 1986;13(4):308-311.
    Challenge. Available from: https://challenge2019.isic-archive.            DOI:10.1111/j.1600-0560.1986.tb01527.x. PMID: 3771875.
    com/. Accessed April 23, 2021.                                      18.   Prieto VG, Casal M, McNutt NS. Lichen planus-like kerato-
 5. ISIC Archive, Pigmented Benign Keratosis Gallery.Available from:          sis. A clinical and histological reexamination. Am J Surg Pathol.
    https://www.isic-archive.com/#!/topWithHeader/onlyHead​                   1993;17(3):259-263. DOI:10.1097/00000478-199303000-00006.
    er​Top/gallery?filter=%5B%22meta.clinical.diagnosis%7Cpig​                PMID: 8434706.
    men​ted%20benign%20keratosis%22%5D. Accessed April 25,              19.   Lim D, Oakley AM, Rademaker M. Better, sooner, more conve-
    2021.                                                                     nient: a successful teledermoscopy service. Australas J Dermatol.
 6. ICD-11 for Mortality and Morbidity Statistics. Available from:            2012;53(1):22-25.DOI:10.1111/j.1440-0960.2011.00836.x.PMID:
    https://icd.who.int/browse11/l-m/en. Accessed July 24, 2021.              22309326.




Original Article | Dermatol Pract Concept. 2023;13(2):e2023115                                                                                 7
