Clinical communication — Kliniese mededeling Uterine adenocarcinoma with transcoelomic metastases in breeder hens (Gallus domesticus)

INTRODUCTION Tumours in commercial poultry are mostly caused by infection with avian herpes, leukosis and retroviruses and thus most studies on avian tumours have been focused on those with viral aetiology, probably due to their economic importance and also because they serve as a model for human cancer studies. Adenocarcinomas in poultry are among the groups of tumours of unknown aetiology, and have been reported by several veterinary pathologists and reviewed. The term adenocarcinoma or peritoneal carcinomatosis has been applied to tumours whose origin cannot be ascertained but that spread widely over the peritoneum and other visceral organs and are frequently observed in aged hens. Spontaneous neoplasms or adenocarcinomas affecting various organs have been reported in specific pathogen-free (SPF) hens and most of these tumours are thought to originate in the oviduct or ovary. A study in Irish abattoirs reported 419 birds with nodules, 80.4 % of which were tumours, and 71.8 % of the tumours were adenocarcinoma of the intestine and reproductive tract. A prevalence of 5–81 % for oviductal adenocarcinomas in end-of-lay hens and 92.9 % for ovarian and oviduct adenocarcinomas in 305 4-year-old layers has been reported. Generally, information on the incidence of nonviral tumours in commercially raised chickens and turkeys is limited, probably due to their shorter life span than that required for the development of such tumours. Also, there are few reports of tumours that are not virally induced because structured surveys are not conducted to assess the situation as they are generally perceived as incidental conditions. Nonviral tumours are also probably considered to be of less economic importance. The present communication reports cases of uterine adecarcinoma in SPF breeder hens (Gallus domesticus) encountered during an experimental virus challenge study.