A solitary encapsulated pelvic aggressive angiomyxoma.

Aggressive angiomyxoma (AAM) was first reported in 1983 as a distinct, slow growing, benign but locally infiltrative, soft tissue tumour. It usually arises in the pelvic and perineal organs, mostly in women. A 47-year-old woman was found to have a large encapsulated retroperitoneal aggressive angiomyxoma. The mass was completely excised via abdomino-perineal approach, and no recurrence noted on MRI at 19 months' follow-up. The encapsulation of this tumour together with other reported rare presentations, suggest an isolated mesenchymal cell origin. A review of the literature is provided.