Nonhematopoietic gastrointestinal neoplasia in cats: a retrospective study of 44 cases.

Gastrointestinal neoplasms other than lymphosarcomas and mast cell tumors were diagnosed in 44 cats during a 14-year period at the Washington Animal Disease Diagnostic Laboratory. All the tumors were malignant; 31 metastasized or recurred. One cat had fibrosarcoma; another, leiomyosarcoma. The other 42 cats had adenocarcinomas, which were subclassified into three histologic patterns: tubular adenocarcinoma; undifferentiated carcinoma; and mucinous adenocarcinoma. The cats averaged 10.6 years of age. There was no sex predisposition. Siamese cats had a higher frequency of adenocarcinomas than other breeds. Osseous and chondroid metaplasia occurred in nine adenocarcinomas.