Hypertrophic Osteopathy Associated with a Prostatic Adenocarcinoma in a Castrated Dog

SIMPLE SUMMARY: The present paper describes a rare case of hypertrophic osteopathy in a castrated dog with prostatic cancer and multiple metastases (lymph nodes, liver, spleen, bones and lungs). Hypertrophic osteopathy is a syndrome characterized by diffuse bone formation along several bones, most often those of the limbs, usually in association with a tumor located in the thoracic cavity (here, pulmonary metastases). ABSTRACT: A 6-year-old mixed-breed male Papillon dog, castrated at the age of 7 months, presented for work-up of a difficulty walking associated with constipation and urinary incontinence. Ultrasonography and radiography were consistent with a tumor of the prostate and lymph node metastases. An irregular osteoproliferation of the ventral edges of L5–L6–L7 suggested tumor invasion. Periosteal proliferative lesions of the pelvis, the femur, the humerus, the tibia and the calcaneus were consistent with hypertrophic osteopathy. Necropsy and histological examination confirmed the diagnosis of prostatic adenocarcinoma with lymph node, pulmonary, liver and bone metastases, associated with hypertrophic osteopathy.