Dermatology: Practical and Conceptual


Image Letter | Dermatol Pract Concept. 2024;14(2):e2024131 1

Pigmented Eccrine Poroma on the Palm Mimicking 
Nodular Melanoma

Inghlide Damanielle Silva1, João Paulo Monteiro Yamagata1, Thales Pereira de Azevedo1, 
Maria Auxiliadora Jeunon Sousa2, Thiago Jeunon de Sousa Vargas2

1 Yamagata Dermatology Clinic, Rio de Janeiro, Brazil

2 Laboratory ID – Investigação em Dermatologia, Rio de Janeiro, Brazil

Citation: Damanielle Silva I, Monteiro Yamagata JP, Pereira de Azevedo T, Jeunon Sousa MA, Jeunon de Sousa Vargas T. Pigmented Eccrine 
Poroma on the Palm Mimicking Nodular Melanoma. Dermatol Pract Concept. 2024;14(2):e2024131.  
DOI: https://doi.org/10.5826/dpc.1402a131

Accepted: December 29, 2023; Published: April 2024

Copyright: ©2024 Damanielle Silva 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: Inghlide Damanielle Silva, Visconde Taunai, 130, 27253380, Volta Redonda (RJ), Brazil.  
Telephone: +55 24988495800. E-mail: doutoradamanielle.ing@gmail.com

Case Presentation

A 48-year-old male presented with a growing brownish 

papule over the preceding three months on the left palm, 

where he reported a previously existing pigmented lesion. 

On physical examination, he displayed a smooth-surfaced, 

brownish papule measuring 2 mm in diameter (Figure 1A). 

Dermoscopic examination revealed a poorly defined brown 

network, erythema, and a grayish-blue veil (Figure 1B). The 

lesion was excised under local anesthesia and sent for histo-

pathological examination, which showed columns of poroid 

cells in continuity with the base of the epidermis and ex-

tending to the superficial dermis (Figure 1C). A closer exam-

ination revealed cuticular cells with abundant eosinophilic 

cytoplasm and an eosinophilic cuticle lining the glandular 

duct (Figure 1D).  Melanin was identified in the cytoplasm 

of the cells, and melanocytes without forming nests among 

poroid cells were seen (Figures 1E, 1F). These findings were 

crucial in ruling out melanoma and confirming the diagnosis 

of pigmented eccrine poroma (PEP).

Teaching Point

Eccrine poromas represent 10% of sweat gland tumors, aris-

ing in the intraepidermal section of eccrine sweat ducts [2]. 

Rarely pigmented, the brownish coloration arises from scat-

tered dendritic melanocytes within tumor cells [1]. There is 

no consensus on the dermoscopic features of PEP. Structures 

like streaks, a white-blue veil, and dermatoscopic structures 

suggestive of regression, common in melanoma, have been 

observed in the histological variant with an epidermal com-

ponent. This complicates an already uncommon diagnosis, 

potentially causing confusion with other pigmented tumors 

like melanoma, pigmented basal cell carcinoma, and Bednar 

tumor [2]. Therefore, histopathological examination is es-

sential for confirming the diagnosis.



2 Image Letter | Dermatol Pract Concept. 2024;14(2):e2024131

References

1. Alfredo MAC, Lai MRR, Miot LDB, Haddad GR, Garcia AL,  

Miot HA. Pigmented eccrine poroma in an atypical loca-

tion.  An Bras Dermatol. 2022;97(5):624-627. DOI: 10.1016/j 

.abd.2021.10.006. PMID: 35118192.

2. Almeida FC, Cavalcanti SM, Medeiros AC, Teixeira MA. Pig-

mented eccrine poroma: report of an atypical case with the use 

of dermoscopy.  An Bras Dermatol. 2013;88(5):803-806. DOI: 

10.1590/abd1806-4841.20131255. PMID: 24173189.

Figure 1. (A) Brownish papule on the left palm. (B) Dermoscopy reveals a poorly defined brown 

network, erythema, and a grayish blue veil. (C) Histological examination shows columns of po-

roid cells in continuity with the epidermis and extending to the superficial dermis. (H&E, x20). 

(D) Poroid cells intermingle with a smaller number of cuticular cells with abundant eosinophilic 

cytoplasm around a small duct lumen with debris (H&E, x400). (E) Abundant melanin was found 

in the cytoplasm of poroid cells (Fontana-Masson, x400). (F) Several dendritic single melanocytes 

were found between poroid cells (MELAN-A, x200).