A rare clinical presentation of pedunculated superficial angiomyxoma in the anal canal: A case report

Superficial angiomyxoma is an infrequent benign soft tissue tumor, clinically presented as slow-growing, painless cutaneous, or subcutaneous mass. It is mostly described in middle aged population with preference location in trunk, head, neck, and genitalia. Herein, we report a rare growth variant of a solitary superficial angiomyxoma with uncommon site of occurrence in a 39-year-old female. Pedunculated superficial angiomyxoma originating in anal canal is extremely rare. Histological features of the lesion comprising of spindle-shaped and stellate cells dispersed in myxoid stroma and prominent thin-walled blood vessels defined the diagnosis of superficial angiomyxoma. Tumor cells with immunohistochemistry analysis showed positivity for vimentin and CD34 and negativity for S100, while Ki-67 showed a low proliferation index. The recurrence of superficial angiomyxoma is previously described, but in our case no signs of recurrence were seen in follow-up for a period of 6 months. Superficial angiomyxoma should be considered as differential diagnosis with other polypoid or nodular masses in anal canal.