Long term survival of primary skeletal muscle lymphoma in a miniature dachshund.

An 8-year-old miniature dachshund presented with a right femoral muscle mass and anorexia. Cytology of the mass revealed a number of small-sized lymphoid cells containing a pleomorphic-shaped dense nucleus and narrow pale cytoplasm. Histopathology indicated that neoplastic lymphoid cells proliferated in skeletal muscles and replaced the muscular architecture. Immunohistochemical and genetic examinations confirmed the diagnosis of primary skeletal muscle lymphoma classified as the pleomorphic small cell type and T-cell low-grade. Although the dog suffered at least three relapses by combination chemotherapy, the dog survived 713 days after the initial presentation.