Primary perianal adenocarcinoma of intestinal type – a new proposed entity

Abstract

Aims

The currently recognised subtypes of anal canal/perianal adenocarcinoma are those arising from low rectal mucosa or columnar cuff, fistula-related tumours and anal gland carcinoma. This following report presents two examples of a hitherto undescribed subtype of perianal adenocarcinoma with an intestinal phenotype.

Methods and Results

A 74 year old man had a perianal tumour locally excised whereas a 73 year old female underwent an abdominoperineal resection for perianal Paget's disease with an underlying carcinoma. Neither patient had a history of perineal fistulae, Crohn's disease or previous gastrointestinal neoplasia, and neither showed clinical, radiological or endoscopic evidence of another abdominal or pelvic tumour. Both resection specimens contained adenocarcinoma which were similar in demonstrating an intestinal morphology and CDX2 immunopositivity. The man has shown a disease-free outcome thus far but the woman has suffered with nodal and pelvic recurrence within a few months of surgery.

Conclusions

The name 'primary perianal adenocarcinoma of intestinal type' is proposed for this previously unrecognised subtype of perineal neoplasia. Awareness of its distinct existence – by recognising its intestinal morphology and immunophenotype while excluding metastasis from the intestinal tract – should help collate data to determine its specific prognosis and to formulate its best management.

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