Spontaneous tumours in guinea pigs

The aim of the study is to describe spontaneous tumours in guinea pigs. Twenty neoplasias from 19 guinea pigs were examined histologically. In 15 cases biopsy samples were examined, samples from four animals were collected during autopsy. Except for one, all animals were kept as pets. Skin tumours were diagnosed in five of them. They appeared in different locations - abdomen, plantar side of hind leg, back (in two animals), and rump, and were of different sizes, the largest one was five cm in diameter. All tumours were of follicular origin - two trichofolliculomas, two trichoepitheliomas, one malignant pilomatricoma. The age of affected animals ranged from two to 7.5 years. Tumours of the mammary gland were present in five guinea pip. Adenocarcinoma was diagnosed in two males, sarcoma of myoepithelial origin was found in one female. Tubular adenoma was present in one two-year-old female, and adenomatous hyperplasia of the mammary gland was observed in another female of the same age. In six guinea pigs, three females and three males, between three and five years of age, there were tumours in subcutaneous tissue. Three were lipomas, in one animal the lipoma was multiple. Liposarcoma was found in one male, myxoid liposarcoma. was diagnosed in another one. Ossifying fibroma was histologically diagnosed in one female. Lymphatic leukaemia was observed in three males. All animals were 4-year-old. Hepatocellular adenoma was found in a 5-year-old female suffering also from trichofolliculoma as mentioned above. Data about tumours in guinea pigs are relatively rare, and therefore information along, this line is useful both for clinical practice and comparative pathology.