Virus-induced pancreatic cancer in guinea fowl: a morphologic study.

The morphologic lesions in the pancreas of 350 guinea fowls infected with avian osteopetrosis virus strain Pts-56 were studied. Focal unspecific changes in the acinar tissue, including reduction of zymogen content, diminution of cytoplasm, and dilatation of acinar lumens accompanied with substitution of the affected acini by tubular structures lined with centroacinar-like cells, developed 2 months from post infection (p.i.) in about 30% of the birds. Adenomatous growths of ductules with mucin-producing or mucin-nonproducing epithelium were observed independently or parallelly to these changes after 3 months p.i. Pancreatic carcinomas arose as early as 4 months p.i. The number and size of the neoplastic foci increased with time, and after the 6th month neoplastic foci were established in almost all infected guinea fowls. Neoplastic proliferations of type A and D endocrine cells were identified in the carcinoma foci of separate cases. Other associated neoplasms were bone tumors and papillomatous growths of the duodenal mucosa.