Multicentric B-cell lymphoma, phaeochromocytoma and amyloid-rich thyroid carcinoma in a common warthog (Phacochoerus africanus): a case of multiple endocrine neoplasia type 2?

Abstract

Neoplastic diseases are poorly documented in Suidae species. This report describes a 15-year-old female common warthog (Phacochoerus africanus) with multicentric lymphoma, phaeochromocytoma and C-cell carcinoma. The animal had multiple episodes of weakness and epistaxis in the months before death, until it was euthanized for acute lethargy and recumbency. Post-mortem examination revealed haemoabdomen originating from enlarged lymph nodes at the mesenteric root. The warthog had generalized lymphadenopathy, consistent with B-cell lymphoma based on CD20 immunohistochemistry. The adrenal glands were bilaterally enlarged, one by an ovoid mass arising from the medulla that effaced the cortex, consistent with a well-differentiated phaeochromocytoma, based on histomorphology and chromogranin A immunopositivity. This animal also had a unilateral, encapsulated thyroid nodule characterized by abundant interstitial calcitonin-positive amyloid and irregular tubular structures, similar to human medullary thyroid carcinoma. There was moderate metastatic calcification of the lungs and upper respiratory mucosa, presumably part of a paraneoplastic syndrome. The combination of phaeochromocytoma and an amyloid-rich thyroid carcinoma in this animal is suggestive of multiple endocrine neoplasia type 2 syndrome which, although well described in humans, is rarely reported in animals. Further investigations of genetic aspects are recommended.