Dear Editor: Traditional theory postulated that ectopic breast tissue could arise at any point along the embryonic milk lines, which extend bilaterally from the axilla to the medial aspect of the upper thigh. In normal circumstances, the majority of the milk lines regress with only a small proportion remaining in the mid-thorax for future breast development. However, a single gene with variable expression regulates natural suppression of the milk lines, and consequently, if some sections fail to regress, accessory breast tissue could develop at any point along their path. The more recent theory suggested by van der Putte (1991) proposed the normal existence of mammary-like anogenital glands and dismissed the traditional theory of ectopic breast tissue. However, this theory does not appear to have been universally accepted with some authors suggesting the presence of both mammary-like glands and ectopic breast tissue in the anogenital region. Here, we report a case of a 59-year-old lady who presented to the outpatient clinic with an anal swelling. It had been present for years but had become more prominent over the preceding 6-months, and she had become aware of it when sitting down. The lump was tender but not pruritic and did not bleed. She was systemically well with no other gastrointestinal abnormality. Her past medical history included a total abdominal hysterectomy for menorrhagia aged 33, hypothyroidism, hypertension, hypercholesterolaemia, carpal tunnel syndrome, and excision of an epidermal exclusion cyst from her back aged 55. Examination revealed a 1×1-cm cystic lesion just below the anal verge at the 5 o'clock position. This was suspected to be a simple skin cyst, and she proceeded to surgical excision. Gross examination of the specimen demonstrated a skin ellipse measuring 13×10 mm with underlying tissue to a depth of 5 mm, and on sectioning, a cyst was present which contained clear fluid. Microscopic examination revealed a well-defined, partially cystic lesion within the dermis. There was a proliferation of ductal structures lined by a dual cell layer. Focally, there were areas of apocrine change, and the large cyst identified macroscopically was lined by apocrine type columnar cells. Several papillary projections were seen to extend into the cyst lumen and some fibrous, focally hyalinised stroma surrounded the ductular structures. The overlying epidermis was essentially normal, and there was no evidence of malignancy. The findings were in keeping with ectopic breast tissue with cystic degeneration. Following a review of the literature, this would appear to be only the second reported case of nonpathological ectopic breast tissue arising in the perianal region. Chan et al. (2007) previously reported a case of ectopic breast tissue that presented as an anal polyp, and there have been five previous reported cases of adenomas detected in the perianal region. More recently, Charfi et al. (2009) described a polypoid lesion in the Competing interests None.
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Jun 1, 2023
Andreia Albuquerque + 1
Open Access
