ABSTRACT
Tumors with cribriform appearance, similar to that of salivary gland adenoid cystic carcinoma, have been described at various anatomic sites. We present an unusual polypoid tumor, discovered incidentally, in the renal pelvis of an elderly man. The mass displayed a prominent cribriform architecture, akin to adenoid cystic carcinoma with an immunophenotype that supported a urothelial origin. Because of its lack of significant invasive growth and other adverse morphologic features, this lesion will likely behave in a banal fashion. This cribriform urothelial neoplasm of the renal pelvis may, in fact, represent a variant of an inverted urothelial neoplasm with a prominent cystic component or florid ureteritis cystica. It is important for pathologists to recognize this growth pattern as a possible variant of urothelial tumors.
Subject(s)
Carcinoma, Transitional Cell/pathology , Neoplasms, Connective Tissue/pathology , Papilloma, Inverted/pathology , Papilloma/pathology , Urologic Neoplasms/pathology , Urothelium/pathology , Aged, 80 and over , Cell Division , Diagnosis, Differential , Humans , Immunophenotyping/methods , Kidney Pelvis/pathology , Male , Proto-Oncogene Proteins c-kit/analysis , Urinary Bladder Neoplasms/pathologyABSTRACT
Simple melanosis of the bladder is an uncommon condition with fewer than 15 reported cases characterized by multifocal, diffuse melanin pigmentation of the urothelial mucosa. It is frequently associated with urinary incontinence or urgency. Histologically, melanin granules are present within urothelial cells or lamina propria macrophages with or without bland-appearing mucosal melanocytes. Although considered a benign entity, the rarity of the lesion warrants regular follow-up cystoscopic evaluation with biopsies to screen for the development of malignancy, especially malignant melanoma. This study presents a "typical" case with light, cytochemical, immunohistochemical, and ultrastructural characterization.
