10.5826/dpc.1301a39
text/xml
2160-9381
2486
en
Alexander Witkowski
https://creativecommons.org/licenses/by-nc/4.0
Dermatology Practical & Conceptual
dermoscopy
Dermoscopy and Reflectance Confocal Microscopy of Apocrine Hidrocystoma
Text.Serial.Journal
https://dpcj.org/index.php/dpc
Research Letter
2023-01-31
2022-03-22
2023-01-31
2023-02-27
e2023039
Dermatol Pract Concept
Alexander Witkowski
2023/01/31
10.5826/dpc.1301a39
e2023039
Department of Dermatology, Oregon Health and Sciences University, Portland, Oregon 
2160-9381
dermoscopy
en
e2023039
Dermoscopy and Reflectance Confocal Microscopy of Apocrine Hidrocystoma
https://dpcj.org/index.php/dpc/article/download/2486/1979
 Dermoscopy and Reflectance Confocal Microscopy
           of Apocrine Hidrocystoma
                 Joanna Ludzik1,2, Claudia Lee2,3, Stephanie Mengden2, Huong Nguyen2,
                              Dennis Pleshakov2, Alexander Witkowski2


1 Department of Telemedicine and Bioinformatics, Jagiellonian University Medical College, Krakow, Poland
2 Department of Dermatology, Oregon Health and Sciences University, Portland, Oregon
3 School of Medicine, University of California Riverside, Riverside, California



Key words: nivolumab, regression, melanocytic nevi, melanoma, dermoscopy
Citation: Ludzik J, Lee C, Mengden S, Nguyen H, Pleshakov D, Witkowski A. Dermoscopy and Reflectance Confocal Microscopy
of Apocrine Hidrocystoma. Dermatol Pract Concept. 2023;13(1):e2023039. DOI: https://doi.org/10.5826/dpc.1301a39
Accepted: May 30, 2022; Published: January 2023
Copyright: ©2023 Ludzik 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: Claudia Lee, BS, Department of Dermatology, Oregon Health and Sciences University, Portland, Oregon 3181 SW
Sam Jackson Park Rd Portland, OR 97239 Email: leecla@ohsu.edu




Introduction                                                             cutaneous lesions, and we review the potential application of
                                                                         this imaging technique in the clinical management of AHC.
Hidrocystomas (AHC) are benign cystic tumors that origi-
nate from apocrine or eccrine sweat glands. While rare, apo-
                                                                         Case Presentation
crine AHC are typically found as solid, asymptomatic blue
to black papules or nodules on the face and neck, especially             Case 1 is a 69-year-old male with Fitzpatrick Skin type III
around the eyelid margin. AHC arises from cystic prolifer-               presented with concerns for a 2-mm homogenous, well de-
ation of the apocrine gland [1], while the eccrine variant is            marcated blue-gray papule on a background of sun-­damaged
caused by the retention of eccrine glands [2]. The etiology of           hyperpigmented skin (Figure 1, A and B). Initial clinical
apocrine AHC is largely unknown [1]. Pigmented AHC of the                assessment was determined as a blue nevus potentially su-
nasal epithelium of the eccrine origin have been reported [3],           perimposed upon a solar lentigo, and a shave biopsy was
but to our knowledge, our case is one of few [4] AHC on                  done to rule out malignant melanoma given the patient re-
the nasal ala reported. Additionally, we report another case             ported history of excessive sun exposure and rapid growth
of pigmented AHC and describe the reflectance confocal                   of the lesion. The specimen routinely stained with hematox-
microscopy (RCM) findings, which are scarce in current
­                                                                        ylin and eosin and histologically diagnosed as a pigmented
literature [5]. Although AHC are benign lesions, based off               AHC. Microscopic examination revealed a cystic structure
clinical appearance alone they are often mistaken for basal              containing focal granular pigmented material whose upper
cell carcinomas, blue nevi, or even melanoma. RCM can                    portion was lined by cuboidal epithelial cells. The lesion was
noninvasively differentiate between benign and malignant                 histologically diagnosed as a pigmented AHC. The specimen



Research Letter | Dermatol Pract Concept. 2023;13(1):e2023039                                                                        1
Figure 1. (A) Clinical image of a darkly pigmented papule located on the left nasal ala. (B) Dermoscopic image of the lesion showing a 2-mm
homogenous blue-gray papule on a background of brown to red sun-damaged skin. (C) Histopathologic image showing a cystic structure
lined by single-to-several layers of cuboidal epithelial cells (arrows) with focal granular pigmented material in the cyst lumen (H&E, x100).




routinely stained with hematoxylin and eosin and histologi-             honey-combed epidermal architecture surrounding a hypo
cally diagnosed as a pigmented AHC (Figure 1C).                         reflective space. Deeper images reveal dark lacunae near nor-
    Case 2 is a 63-year-old male presented with a history of            mal adnexal structures (Figure 3A), representative of cystic
non-melanoma skin cancer who presented with concerns                    spaces. These findings along with the absence of concerning
for an asymptomatic lesion located on his central forehead.             features such as pagetoid cells or non-edged papillae favored
The patient reported that the lesion has been present for an            diagnosis of a benign AHC. However, due to patient con-
unknown amount of time but has recently grown in size                   cern for the growing lesion, the lesion was removed using
over the last few months. Clinical and dermoscopic exam-                a shave biopsy technique and histopathological assessment
ination revealed a well demarcated 4-mm blue homogenous                 illustrated a cystic space lined by several layers of cuboidal
papule (Figure 2, A and B). The lesion was further evalu-               epithelial cells, confirming the diagnosis of pigmented AHC
ated with RCM (Vivascope 1500) which revealed a normal                  (Figure 3B).



2                                                                            Research Letter | Dermatol Pract Concept. 2023;13(1):e2023039
Figure 2. (A) Clinical image of a single darkly pigmented papule located on the central forehead. (B) Dermoscopy image demonstrating a
4-mm blue-violet homogenous well-demarcated papule.




Conclusions                                                          nasal ala, contributing to the literature of other variants,
                                                                     including eccrine [19] and planar AHC variants [20],
This paper reports a unique anatomical presentation of an            ­reported on the nasal ala.
apocrine variant of pigmented AHC and discusses the dif-                It is important to utilize advanced imaging technologies
ferential diagnosis of pigmented papules or nodules on the           to discern differential diagnosis of blue skin lesions with
body, specifically blue nevi and melanoma. AHC can grossly           malignant potential, such as blue nevi, BCC, and melanoma
present as a blue papule or nodule that can be mistakenly            from a completely benign entity like hidrocystoma. Recog-
clinically diagnosed as a blue nevus, pigmented basal cell car-      nizing the absence of certain features of BCC such as bright
cinoma (BCC), or even melanoma. While AHCs and blue nevi             tumor islands with abundant vasculature and pleomorphism
are benign, skin cancers like BCC and melanoma have malig-           of the overlying epidermis [21-24] or features like nucleated
nant potential, thus histologic evaluation can be of benefit.        round, dendritic, or spindled cells and non-edged papillae
Blue nevus-like melanomas have two reported ­pathogenesis:           which can be found in melanocytic lesions with malignant
melanoma arising coincidentally with a benign blue nevus             potential like blue nevi or melanoma [25] can provide cli-
or arising de novo and mimicking a blue ­nevus [6]. While            nicians with enough confidence to safely monitor the lesion
rare, it is important to note an initially benign blue nevus         without sampling. The clinical benefits of utilizing RCM
also has the potential to become malignant [7-9]. AHC may            include prevention of unnecessary biopsies, decreased pain,
be benign, however it is important to be familiar of other           improved cosmetic outcomes, and enhanced surveillance
malignancies with similar clinical presentations as potential        for recurrent malignancy [26]. Data on RCM characteris-
differential diagnosis.                                              tic findings for hidrocystomas is scarce in current literature
   Familiarity with features of AHC may promote accu-                [4,22] and we provide further evidence supporting the fea-
rate clinical diagnosis and avoid the unnecessary finan-             tures of hidrocystoma commonly seen on RCM including
cial, cosmetic, and psychological implications associated            homogenous cystic structures adjacent to normal‐appearing
with physical biopsies. AHC tend to appear as a solitary,            adnexal structures.
homogeneous papule or nodule, typically ranging in size                 The variations and overlapping features in the clin-
from 3-15mm [10], either skin-colored or with pink,                  ical presentation of AHC, blue nevus, melanoma and
­yellow or blue color hue, and can have secondary features           non-melanoma skin cancer may make it challenging to dic-
such as arborizing vessels seen under dermoscopy [11].               tate appropriate management therefore, it is important to
AHC most commonly appears on the eyelid margins                      consider the diagnosis of pigmented AHC clinically when
[12-15], oral mucosa [16,11,17] and ear [11,17,18]. We               there is a suspicion of blue nevus, BCC, or melanoma.
would like to report that both our cases of AHC, when                ­Dermoscopic and reflectance confocal microscopic assess-
compared to more classical presentations, do not have ar-            ment of the lesion aids in an accurate diagnosis which may
borizing vessels, and has a less common location on the              to guide appropriate patient care.



Research Letter | Dermatol Pract Concept. 2023;13(1):e2023039                                                                       3
Figure 3. (A) Reflectance confocal microscopic image of the superficial dermis reveals adnexal structures (yellow star) surrounded by several
hypoechogenic lacunae (yellow arrows) representative of cystic spaces. (B) Histopathologic image showing a cystic lumen with the upper por-
tion demonstrating an attenuated lining containing 2 layers of flattened to cuboidal epithelial cells (arrows) and pigmented brown granular
material (star) in the cystic space (H&E, x100).




4                                                                            Research Letter | Dermatol Pract Concept. 2023;13(1):e2023039
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Research Letter | Dermatol Pract Concept. 2023;13(1):e2023039                                                                                 5
