Introduction
Anal (or perianal) skin tag, abbreviated in the remaining text as (AST) is an excess skin which occur around the anus as a polyp.1
Different conditions have been reported to present as AST or to be found in its pathological examination in neonatal, childhood and adulthood periods.
These include, rhabdomyomatous mesenchymal hamartoma,2 colorectal cancer implant,3 a tubulopapillary apocrine hidradenoma with an adenocarcinoma arising in it,4 eccrine nevus,5 food protein-induced allergic proctocolitis.6
Herein, we are reporting a melanocytic nevus presenting as AST, after obtaining a conset from the patient for the publication.
Case Report
A 75-year-old Saudi male, not known to have chronic medical problems before, presented with a perianal skin tag for many years.
The histopathological examination of the excised polyp revealed an intradermal nests of melanocytes, Figure 1A, B.
Figure 1
A polypoid epithelial polyp containing intradermal nests of melanocytes. Hematoxylin and eosin; X 20 magnification (A). A close view of melanocytic nest. Hematoxylin and eosin; X 40 magnification (B).
No noticeable cellular atypia or abnormal mitotic figures seen.
The melnaocytic (HMB45 and Melan A) markers and the Ki67 stain, confirmed the melanocytic nature of the lesion and its low proliferative activity.
Discussion
AST is distinct from skin tag (acrochordon) developing in the skin elsewhere in the body.
It is not always possible to identify the actual cause of AST in each patient but its occurance can be associated with genetic predisposition, follow a period of diarrhea and frequent wiping and irritation to the anus, haemorrhoids, chronic anal fissue (sentinel tag), previous pregnancies or surgeries, obesity, aging, chronic perianal dermatoses, and inflammatory bowel diseases (IBD) mainly Crohns disease.1
AST may reveal also the diagnosis of Crohns disease.1
AST is usually asyptomatic but it can cause a discomfort and can be itchy Individuals may complain from it due to hygiene issues or cosmesis. The differentials of AST may include wart or piles. AST can be treated by surgical excision.
Anal Melanocytic nevi (AMN) are not common.7
In her review, Aljufairi found only seven definte cases. She added three new cases all of them associated with piles.
We are not aware of any published report of AMN presenting as AST.
Similar to other authors,7 we wish to stress the importance of pathological studies of any excised perianal skin tags.
Reporting any incidental findings even if benign, is important to better understand the pathogenesis of different conditions affecting anal area.
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