Angiomyxoid tumour in the renal peripelvic tissues with features of aggressive angiomyxoma.

A case of angiomyxoid tumour in the renal peripelvic soft tissue of a 45 year old woman is reported. The encapsulated tumour, measuring 12 x 9 x 6 cm, was solid and firm. The cut surface revealed a yellowish-white, gelatinous, and glistening tumour. Histologically, the tumour was composed of loosely textured spindle and stellate cells with prominent blood vessels of variable calibre. The tumour cells stained strongly for vimentin. These findings strongly resemble those associated with aggressive angiomyxoma in the vulva and perineum.