Spontaneous tumors of the prostate gland in inbred strains of mice.

Spontaneous tumors of the prostate gland in the house mouse (Mus musculus) have rarely been described. In a histologic survey of prostate glands from old (greater than 700 days of age) mice, we have observed 2 primary adenocarcinomas of the prostate gland, 1 in a 1,047-day-old C57BL/6J mouse (DEH 1009) and 1 with metastases to the kidney and lungs in a 778-day-old C57BL/KsJ mouse (DEH 705C). We have also found a rhabdomyosarcoma of the prostate gland in a C57BL/6J mouse (DEH 1121C) 732 days old. The histologic characteristics of these tumors, and of the prostate glands of mice of similar ages without prostatic neoplastic involvement, including a 736-day-old CBA/CaJ mouse (DEH 849) with adenomatous hyperplasia, are described.