Undifferentiated pleomorphic sarcoma (atypical fibroxanthoma‐subtype) in a 4‐year‐old Rothschild's giraffe (Giraffa camelopardalis rothschildi)

Abstract

A 4‐year‐old, male Rothschild's giraffe presented with a rapidly growing, hemispherical, approximately 40 × 20 × 20 mm, raised, firm mass located on the mid‐region of the left lateral thigh. Complete surgical excision (minimal 20 mm margins in all orientations) was achieved under behavioural restraint and local anaesthesia. Cytology and histopathology diagnosed a poorly differentiated malignant mesenchymal neoplasm, with nuclear karyomegaly, multinucleation and atypical horseshoe‐like forms. The neoplastic cells exhibited diffuse strong cytoplasmic immunopositivity to vimentin, and were negative to smooth muscle actin, desmin, glial fibrillary acidic protein, and CD18 immunomarkers, giving a diagnosis of undifferentiated pleomorphic sarcoma. At 1 year follow‐up, the giraffe is clinically well with no health issues after complete excision, and no evidence of local recurrence or distant metastases, based on physical examination and routine haematology/biochemistry. To the authors’ knowledge, this is the first report of an undifferentiated pleomorphic sarcoma (atypical fibroxanthoma‐subtype) in a giraffe.