Multiple metaphyseal involvement of a thymic lymphoma associated with hypercalcemia in a puppy

A six-month-old, female German shepherd dog was presented because of depression, anorexia, vomiting, polyuria, and polydipsia of approximately 10 days' duration. The puppy was depressed, and pain could be elicited on palpation of both shoulders and hips. The most significant results of serum chemistries and hematology were hypercalcemia; increased blood urea nitrogen, creatinine, and alkaline phosphatase; and leukocytosis with neutrophilia. Thoracic radiographs revealed a large thymic mass, diagnosed on histological examination as a thymic lymphoma. Radiographs of the shoulders revealed destructive bone lesions involving the proximal metaphyses of the humeri, causing slipped epiphyses. Bone lesions were found at necropsy on the proximal and distal aspects of both humeri and femurs. Bone resorption was due to local neoplastic infiltration and presumed humoral factors secreted locally and systemically by neoplastic thymic lymphocytes.