Pathomorphology of bovine tuberculous granuloma

The pathomorphology of the 24 granulomatous lesions were studied in paraffin embedded HE stained sections. Staging of granulomas was done as per the microscopic observations of tissue sections. The stage IV granuloma was encountered with maximum frequency, although, variable number of all four stages granulomas were seen in the same lung tissue. The cases of generalized tuberculosis with extra pulmonary tubercles had more numbers of microscopic features of stage III granuloma in the pulmonary tissue. Stage IV (necrotic and mineralized) granulomas were characterized by a thick fibrous capsule surrounding irregular multicentric granulomas with multiple necrotic cores. The present study on tuberculous lesions in bovine revealed different stages of the granuloma in naturally occurring cases with a predominance of stage IV granuloma.