Some observations on naturally occurring neoplasms of domestic fowls in the State of Victoria, Australia (1977-87).

In the 10 years to November 1987, 33 different types of naturally occurring neoplasms were diagnosed in 2281 domestic fowls submitted for necropsy examination. The most prevalent type was lymphoma (1825/2281 = 80%) including two cases in chickens from a flock free from Marek's disease virus, exogenous avian leukosis viruses and reticuloendotheliosis virus; the remaining lymphomas were diagnosed on gross and/or histological criteria as Marek's disease (1069) or lymphoid leukosis (754). Of the non-lymphoid neoplasms, leiomyomas of the ventral ligament of the oviduct (99) were the most common followed closely by metastatic abdominal adenocarcinomas (93) and haemangiomas or haemangiosarcomas (91). A large number of fibromas and fibrosarcomas (40), and a smaller number of myxomas and myxosarcomas (17) were observed. Three fibrosarcomas and two myxosarcomas were presented as metastatic abdominal neoplasms, and two fibromas and seven myxomas were found on the rostral extremity of the upper beak of hens, including five cases of myxoma from one flock. Other less prevalent neoplasms described were myelocytomas or myeloblastomas (12), avian keratoacanthomas (11), granulosa-theca cell tumours (11), oviduct adenomatosis and adenocarcinomas (10) and ovarian adenocarcinomas (8). Small numbers of some neoplasms or well-characterized variants were encountered, namely histiocytic sarcomas (5), lipomas (4), liposarcomas (2), reticulum cell sarcomas (3), plasmacytomas (3), intracutaneous keratinizing epitheliomas (3), feather folliculomas (2), proventricular adenomas (2), hepatocellular adenocarcinomas (2), cholangiocellular adenomas and adenocarcinomas (6), pancreatic adenocarcinomas (3), nephroblastomas (7), astrocytomas (5), pinealomas (3), Schwannomas (3) and multifocal melanomas (3). Single examples were found of osteoma, osteosarcoma, rhabdomyosarcoma, leiomyoma of the gizzard wall, intestinal adenocarcinoma, renal adenocarcinoma, adrenocortical adenoma and ultimobranchial cyst.