Pathology in Practice

Abstract

HistoryAn approximately 10-month-old female Syrian hamster (Mesocricetus auratus) was submitted for necropsy. The pet had died following a 6-week period of weight loss, lethargy, and tachypnea with increased abdominal effort. The hamster was previously evaluated by a veterinary ophthalmologist because of several small nodules on both lower eyelids at the medial canthus; on the basis of the physical examination findings, these nodules were diagnosed as cysts.On external examination of the hamster, there were dozens of slightly raised, light pink to pale tan cutaneous nodules (range of diameter, 0.1 to 0.2 cm; Figure 1). The nodules were scattered over the back, ventral aspect of the abdomen, limbs, neck, and chin and were of similar appearance to the masses on the lower eyelids. The thoracic cavity was filled with white, opaque fluid (chylous effusion), and there was a soft, pale tan, multinodular mass (1.5 X 1 X 1 cm) at the base of the heart. The liver was diffusely and markedly enlarged (congestion).

Hamster polyomavirus-associated T-cell lymphomas in Syrian hamsters (Mesocricetus auratus)

“…HaPyV may induce T-cell and B-cell lymphomas. 4,5,15 A previous study on the HaPyV pandemic in a colony of GASH: Sal Syrian hamsters reported a high incidence of non-Hodgkin, Burkitt-type B-cell lymphoma in affected hamsters. 20 HaPyVassociated lymphomas in the abdominal cavity have been suggested to possess the B-cell immunophenotype, while those in the thymus possess the T-cell immunophenotype.…”

“…Cases of HaPyV infection have been reported in the United States and Europe. 5,11,20,27 There are 3 main outcomes of HaPyV infection: subclinical effects, trichoepithelioma, and lymphoma. 4,15,26 HaPyV infection in older hamsters is typically subclinical and the virus persists in the renal tubular epithelium, resulting in continued viruria.…”

“…Although the life cycle and pathogenicity of HaPyV have been extensively examined in experimental infections, few clinical studies have investigated HaPyV-associated lymphoma in Syrian hamsters outside of the laboratory, and most are individual case reports. 5,27 Previous epidemiological studies on spontaneous tumors in pet hamsters did not examine the involvement of HaPyV in lymphoma cases. 16,23 Therefore, the aims of the present study were to characterize the pathological findings of lymphomas in pet Syrian hamsters and investigate the prevalence of HaPyV in these cases.…”

Hamster Polyomavirus Research: Past, Present, and Future

“…The tumors appeared spontaneously in young animals of about 3 months to more than one year of age. Polyomavirus infections in hamsters were also reported from the United States (Newfield, NJ [ 16 ]; Columbia, MO [ 17 ]; New Haven, CT [ 18 ]) and Europe (Bristol, GB [ 19 ]; Salamanca, Spain [ 20 ]). In general, HaPyV infections are rarely reported.…”

“…The invasion of adjacent tissue and metastasis occur often. The concurrent formation of skin tumors and lymphoma in a hamster individuum is a relatively rare event [ 18 ].…”