Anotace:
The aim of this study was to investigate the incidence of spontaneous tumours in guinea pigs in biopsy and necropsy samples in the monitored period (2016–2022) on a representative number of cases and to determine their occurrence in relation to age and sex of the animals. A total of 204 samples from various pathological lesions were examined, while 153 cases (75.00%) were true tumours and 51 cases (25.00%) were pseudotumorous non-neoplastic lesions. The distribution of the incidence of true neoplasms in relation to sex was uneven. In the examined group, more neoplasms were diagnosed in males (n = 88, 57.52%) compared to females (n = 65, 42.48%). The mean age of guinea pigs with diagnosed tumour in our group was 4.2 years. Thyroid adenocarcinoma was the most frequent tumour. The majority of thyroid tumours (67.86%) were diagnosed in animals aged 4–5 years, as a significant result in terms of incidence in this age range, as well as a predisposition to tumour formation in males (78.57%). Mammary gland tumours occurred in the age range of 2–7 years, with a mean age of incidence of 4.7 years. In all cases, these were malignant variants and showing a significant higher incidence in males, in the age range of 4–5 years. The processing of a representative number of samples and epidemiological data on the incidence of spontaneous tumours in guinea pigs can contribute to the overall expansion of knowledge about this topic in veterinary medicine.