Spontaneous tumors of the European hamster -Cricetus cricetus L.-.

The incidence and spectrum of spontaneously occuring 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 tumor-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 cementoblastom a 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.