1. a type of squamous cell carcinoma of the anus originating in tissues arising from, or in remnants of, the cloaca.
2. in oncology, anal cancer arising proximal to the pectinate line.
[cloaca + -genic]
A subtype of squamous cell carcinoma arising at the anorectal transition zone, which comprises 20% of all anal carcinomas. It is linked to HPV infection and more common in homosexual males, implicating anal intercourse as a vector. It has been variously reported as having either a better or worse prognosis than standard anal cancer.
A form of large cell carcinoma (non-small cell type), in which at least 50% of the cellular component is a basal cell carcinoma; it is often high-grade with 15–50 mitoses/10 HPF, and has a dismal prognosis by some authors as a type of squamous cell carcinoma.
p63, CK 5/6 +ve.
Poorly differentiated squamous cell carcinoma, small cell carcinoma, large cell neuroendocrine carcinoma.
Small cuboidal or fusiform cells; lobular or tentacular invasion, peripheral palisading.
Probably worse than stage-matched squamous cell carcinoma.
Aggressive, rapidly growing; nodes are involved in 2/3 at time of diagnosis; distant metastases frequent (37–50%); age/site/stage/treatment matched-case control studies have the same prognosis as high-grade conventional SCC.