Inflammatory pseudotumor (pseudosarcoma) of the bladder.

Inflammatory pseudotumor (pseudosarcoma) of the bladder is a benign proliferative lesion of the submucosal stroma easily mistaken for a malignant neoplasm clinically and histologically. The lesion was first described as a separate entity in a report of 2 patients. Three additional cases have been reported since then. We describe pseudosarcomatous bladder tumors arising in 2 adolescents. Both patients presented with sudden onset of gross painless hematuria related to large polypoid and ulcerated bladder masses found on endoscopy. Initial pathological analysis was interpreted as poorly differentiated sarcoma in both patients but subsequent reviews were consistent with a benign process resembling nodular fasciitis. Simple excision in both patients has been successful in eradicating the lesion. The findings in these 2 patients are described with a discussion of the pathophysiology and review of the literature.