Small Cell Carcinoma of Anal Canal: A Rare Case Report from a Tertiary Cancer Centre

Abstract

Extrapulmonary small cell carcinoma (EPSCC) is very rare with an incidence of 0.1 to 0.4% in the United states and the exact incidence in other regions is unknown. Anal canal involvement is extremely rare contributing to < 1% of all EPSCC. Inspite of its rarity, it is of clinical importance due to its aggressive nature. Most of the patients present with lungs and liver metastasis at diagnosis even in early stage tumors. It has a dismal survival rate of 58% at 6-month and 6% at 5-years in contrast to squamous cell carcinoma of anal canal. Exact ethiopathogenesis is unknown. Association with HIV has been seen like squamous cell carcinoma of anal canal. There is very little literature evidence and management is not clear like that of squamous cell carcinoma anal canal. Here we present the case of a 63 year old HIV positive male who presented with small cell carcinoma of anal canal to our institute and the challenges we faced in diagnosis and management.