MULTIPLE METAPHYSEAL INVOLVEMENT OF A THYMIC LYMPHOMA ASSOCIATED WITHHYPERCALCEMIA IN A PUPPY

A six-month-old, female German shepherd dog was presented because of d epression, anorexia, vomiting, polyuria, and polydipsia of approximate ly 10 days' duration. The puppy was depressed, and pain could be elici ted on palpation of both shoulders and hips. The most significant resu lts of serum chemistries and hematology were hypercalcemia; increased blood urea nitrogen, creatinine, and alkaline phosphatase; and leukocy tosis with neutrophilia. Thoracic radiographs revealed a large thymic mass, diagnosed on histological examination as a thymic lymphoma. Radi ographs of the shoulders revealed destructive bone lesions involving t he proximal metaphyses of the humeri, causing slipped epiphyses. Bone lesions were found at necropsy on the proximal and distal aspects of b oth humeri and femurs. Bone resorption was due to local neoplastic inf iltration and presumed humoral factors secreted locally and systemical ly by neoplastic thymic lymphocytes.