Incidence and description of ovine pulmonaryadenocarcinoma from 2000 abbatoir lungs.

摘要

Ovine pulmonary adenocarcinoma(OPA), known as Jaagsiekte, is a contagious lung tumor of sheep caused by beta-retrovirus(Jaagsiekte sheep retrovirus: JSRV). Neoplastic transformation occurs in pneumocyte type II andClara cells. Diagnosis of OPA is based on clinical history, pathologic findings and moleculartechniques. After inspection of 2000 lungs OPA was diagnosed in 16 (0.8%) lung samples.Immunohistochemistry and polymerase chain reaction (PCR) were performed on affected lungsand associated lymph nodes and revealed classic (n=10/16) and atypical (n=6/16) forms. In theclassic OPA, firm, white to grayish nodules were grossly observed in the cranioventral lobes. Thecut surface of the lungs appeared wet with frothy fluid exudate in airways. In the atypical OPAlesions were distributed as small clearly demarcated nodules mainly in the diaphragmatic lobeswithout fluid in airways. Pneumocyte type II and Clara cells proliferated in an acinar and papillarypattern. The stroma of the atypical form asppeared more infiltrated by connective tissue andmononuclear cells than the classic form. No metastatic lesions were observed in regional lymphnodes. JSRV capsid protein was detected immunohistochemically in pneumocytes type II, Claracells, alveolar macrophages, lymphocytes and plasma cells of the neoplastic regions andsurrounding tissues. In regional lymph nodes, lymphoid follicles and infiltrated macrophagesshowed strong positive results for JSRV-CA. PCR detected JSRV in all 16 affected lungs.