Congenital mesoblastic nephroma in a dog: a benign variant of nephroblastoma.

摘要: A nephroblastoma consisting predominantly of mature mesenchymal components developed in a 7-month-old male beagle dog. The dog was necropsied after experimental use. There were no abnormal signs or laboratory tests prior to necropsy. left kidney slightly enlarged, and the tumorous area gray-white. cut surface tumor, occupying upper one-third kidney, revealed solid, rubbery, yellow-white mass. tumor about 3.0 cm its greatest diameter, showed replacement growth pattern, lacked capsule (Fig. 1). Histologically, mainly composed spindle cells arranged interlacing bundles that intermingled with normal renal tissue; however, there sharp demarcation between surrounding parenchyma. greater part had loose myxomatous pattern an alcian blue-positive matrix, but dense, cellular, fibromatous areas transition also noted 2). Spindle (fibroblasts) scanty cytoplasm cigar-shaped nuclei negative for phosphotungstic acid-hematoxylin staining. Neither nuclear atypia nor mitotic figures detected. Within area, cysts various sizes recognized addition entrapped nephrons. small dilated