Epithelioid cells in mediastinal lymph nodes of cattle without cancer

Multicentric Benign Epithelial Inclusions in a Free-ranging Risso's Dolphin (Grampus griseus)

This report describes the histological and immunohistochemical features of multicentric, benign, epithelial inclusions (BEIs) in a free-ranging, adult, female Risso's dolphin (Grampus griseus). The differential diagnoses included ectopic hamartomatous epithelial inclusions, non-Müllerian choristoma, Müllerian choristoma and low-grade metastatic carcinoma/mesothelioma. The most likely diagnosis of such BEIs was multicentric, embolic, reactive mesothelium, as suggested by cytomorphological and immunophenotypical features of the BEIs, the occurrence of focal pleural rupture and the immunophenotype of the pleural mesothelium. The former represents a pathological condition not previously reported in a marine mammal species, rarely described in animals, and relatively infrequently recognized in man.

Epithelial and pancreatic choristoma in bovine lymph nodes

Lymph nodes from 186 cows were evaluated as part of a bovine tuberculosis eradication programme. The mediastinal lymph nodes of 13 animals contained atypical structures. In 12 cases (6.45%) these consisted of multiple epithelial structures and, in one case, of pancreatic-like tissue. Immunohistochemistry (IHC) revealed that the epithelial structures were consistent with respiratory epithelium and with ectopic pancreatic tissue, respectively. To the best of our knowledge these are the first histological and immunohistochemical descriptions of epithelial and pancreatic choristomas in bovine lymph nodes.