10.5826/dpc.1204a175
text/xml
2160-9381
2186
en
Sebastian Podlipnik
https://creativecommons.org/licenses/by-nc/4.0
Dermatology Practical & Conceptual
Lichenoid keratosis simulating melanoma: A case report.
Text.Serial.Journal
https://dpcj.org/index.php/dpc
Image Letter
2022-10-31
2021-11-18
2022-10-31
2022-12-01
e2022175
Dermatol Pract Concept
Sebastian Podlipnik
2022/10/31
10.5826/dpc.1204a175
e2022175
Melanoma Unit, Dermatology Department, Hospital Clínic de Barcelona, IDIBAPS, Universitat de Barcelona, Barcelona, Spain.
2160-9381
en
e2022175
Watanabe S, Sawada M, Dekio I, Ishizaki S, Fujibayashi M, Tanaka M. Chronology of lichen planus-like keratosis features by dermoscopy: a summary of 17 cases. Dermatol Pract Concept. 2016;6(2):29-35. Published 2016 Apr 30.
Lichenoid keratosis simulating melanoma: A case report.
https://dpcj.org/index.php/dpc/article/download/2186/1805
            Lichenoid Keratosis Simulating Melanoma:
                          a Case Report
                 Leire Barrutia1,2, Nelson Lobos1, Josep Malvehy1, Sebastian Podlipnik1


1 Melanoma Unit, Dermatology Department, Hospital Clínic de Barcelona, IDIBAPS, Universitat de Barcelona, Barcelona, Spain.
2 Dermatology Department, Clinical University Hospital of Valladolid, Valladolid, Spain.



Citation: Barrutia L, Lobos N, Malvehy J, Podlipnik S. Lichenoid keratosis simulating melanoma: A case report. Dermatol Pract Concept.
2022;12(4):e2022175. DOI: https://doi.org/10.5826/dpc.1204a175
Accepted: January 5, 2022; Published: October 2022
Copyright: ©2022 Barrutia 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: Leire Barrutia, MD, Dermatology Department, Clinical University Hospital of Valladolid – Edificio Rondilla. Calle
Rondilla Sta Teresa s/n, 47010, Valladolid, Spain. E-mail: leirebarrutia4@gmail.com




Case presentation                                                        Therefore, both confocal microscopy and histopathology
                                                                         were compatible with lichen planus-like keratosis (LPLK).
An 80-year-old male was referred to the Dermatology De-
partment for a pigmented lesion on his right arm that had
been present for over twenty years but had rapidly grown
                                                                         Teaching point
and become more pigmented in the last three months. Physi-
cal examination showed a 10 mm dark, bluish-brown plaque                 The diagnosis of seborrheic keratosis is typically straightfor-
and dermoscopy revealed a multicomponent pattern with                    ward. However, in cases of regression, also known as LPLK,
multiple colors and pseudopods (Figure 1B). Reflectance                  these lesions may mimic melanoma or other malignancies
confocal microscopy was performed, and the most prom-                    [1]. Dermoscopic findings of lichenoid keratosis change
inent findings were a regular epidermal architecture, rem-               as regression progresses, and several patterns have been
nants of cord-like pattern in the dermoepidermal junction,               described, such as light-brown or gray pseudo-networks,
and abundant aggregates of plump-bright cells in the pap-                annular-granular structures and blue-gray globules [2]. We
illary dermis, corresponding to melanophages (Figure 1C).                present a case in which some of those features were pres-
An excisional biopsy was performed, and histopathological                ent, but were accompanied by other structures than have not
analysis showed epidermal hyperplasia with hyperkeratosis,               been described yet in LPLK and that can be very misleading,
vacuolar-interface dermatitis, and a dense dermal infiltrate             such as pseudopods and blue-gray veil. Confocal microscopy
of melanophages and lymphocytes. SOX10 stain high-                       was particularly useful in this challenging case, and diagno-
lighted dermal melanophage-aggregates (Figure 1, D and E).               sis was confirmed by histopathology.




Image Letter | Dermatol Pract Concept. 2022;12(4):e2022175                                                                               1
Figure 1. (A) Physical examination showed a 10 mm bluish-brown plaque. (B) Dermoscopy revealed a multicomponent pattern with mul-
tiple colors, and asymmetrically distributed blue-gray globules. Moreover, diffuse peripheral projections coalescing into pseudopods were
observed on the left bottom side, and blue-gray veil and annular-granular structures in the center. (C) Reflectance confocal microscopy
showed remnants of cord-like pattern, and aggregates of small-bright particles in the papillary dermis, corresponding to melanophages.
(D) Histopathology, H&E 200x. Epidermal hyperplasia with hyperkeratosis, vacuolar-interface dermatitis and a dense dermal infiltrate of
melanophages and lymphocytes. (E) SOX10 (Sry-related HMg-Box gene 10), 400x. Absence of melanocytic hyperplasia, and dermal mela-
nophage-aggregates can be observed.




References                                                                2. Watanabe S, Sawada M, Dekio I, Ishizaki S, Fujibayashi M,
                                                                             Tanaka M. Chronology of lichen planus-like keratosis features
 1. Ramirez-Fort MK, Al Jalbout S, Kittler H, Pellacani G. Lichenoid         by dermoscopy: a summary of 17 cases. Dermatol Pract Con-
    keratosis: non-invasive imaging in the setting of diagnostic uncer-      cept. 2016;6(2):29-35. DOI: 10.5826/dpc.0602a06. PMID:
    tainty. Dermatol Pract Concept. 2013;3(2):63-65. DOI: 10.5826/           27222769. PMCID: PMC4866624.
    dpc.0302a10. PMID: 23785648. PMCID: PMC3663400.




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