Fibromatosis and/or desmoid tumors which constitute less than 1% of all neoplasms and 3.0% of all soft-tissue tumors are pathologically benign proliferations of the fibroblasts but are locally aggressive with infiltrative type of growth and tendency toward recurrence. Bilateral symmetrical perirenal involvement has been described in many conditions which can be renal, subcapsular, or perirenal in origin. However, bilateral perirenal fibromatosis as an isolated presentation was very uncommon. We report an exceptionally rare case of bilateral perirenal fibromatosis with renal infiltration.
Keywords: Perirenal fibromatosis; Perirenal lymphangiomatosis; Perirenal lymphoma; Perirenal space.