Pathological femoral fracture due to rhabdomyosarcoma in a cat

An eight-year-old neutered male domestic shorthaired cat was presented with non-weightbearing lameness of the right hindlimb. On radiography, a pathol ogical, metaphyseal femoral fracture was apparent, with areas of bony lysis directly surrounding the fracture site. The cat underwent amputation of th e limb. Histopathological examination revealed the presence of a tumour of mesenchymal cells with cytoplasm-containing vacuoles which stained positive with the periodic acid-schiff reaction, indicative of glycogen granules th at may be found in rhabdomyosarcoma cells. In addition, the tumour cells st ained positive for vimentin and desmin on immunohistochemical examination, thus confirming the diagnosis of rhabdomyosarcoma. In spite of the radical surgery performed, the cat was euthanased due to a recurrence at the amputa tion site four and a half months later.