Although the original WHO classification listed this tumor under the category "adenocarcinoma of anal glands," these tumors may actually arise from or be related to anal ducts that drain the anal glands, and may therefore be more appropriately termed anal duct adenocarcinoma.
Moreover, carcinomas associated with anal fistulae are often mucinous, and it remains to be determined if at least some of such fistula-associated tumors are actually of anal gland or anal duct origin.
The differential diagnosis includes a wide variety of conditions that occur in the retro rectal space: cystic sacrococcygeal teratoma, anterior sacral meningocele, anal duct
or gland cyst, necrotic rectal leiomyosarcoma, extraperitoneal adenomucinosis, cystic lymphangioma, pyogenic abscess, neurogenic cyst, and necrotic sacral chordoma.
Fistula-in-ano, an investigation of human foetal anal ducts
and intramuscular glands and a clinical study of 150 patients.
When problems are manifested by scooting or persistent licking of the anus, however, they usually have to do with the consistency of the glandular secretions or the anatomical structure of the anal ducts
, says Dr.
Most tumours present as fungating or ulcerating lesions but the tumour may arise in anal ducts
and present as submucosal mass.