Spontaneous tumours of the European hamster (Cricetus cricetus L.).

The incidence and spectrum of spontaneously occurring neoplasms was evaluated in 285 European hamsters (strain Mhh:EPH) ranging in age between 1 and 5 years. The mean lifespan of the 107 male and 135 female hamsters examined amounted to 122 and 135 weeks, respectively. The overall incidence of tumour-bearing animals was 51.2% (males: 57.9%, females: 47.2%). Malignant tumours were more frequent than benign neoplasms and affected more males than females. Neoplasms of the haematopoietic/lymphoreticular system were the most common tumours (males: 16.8%, females: 13.5%). In males, these were followed in a decreasing order of incidence by pheochromocytomas (15.9%), malignant schwannomas (8.4%) and tumours of the prostate (6.5%). In females, pheochromocytomas as well as granulosa cell tumours were the second commonest tumour types (6.2% each), followed by malignant schwannomas (5.1%). Other tumours did not exceed the 5% incidence level. Two unusual rare tumours were a locally invasive cementoblastoma arising in the maxilla and a carcinosarcoma of the skin with components of a squamous cell carcinoma and a neurofibrosarcoma. The results of the study are compared with data on the Syrian and Chinese hamster.