TTF-1 positive small cell cancers: Don't think they're always primary pulmonary!

Abstract

Thyroid transcription factor 1 (TTF-1) plays a key role in morphogenesis of the lungs and is expressed in up to 90% of pulmonary small cell carcinomas. This explains why this marker is frequently used in the search for the primary origin of metastatic endocrine tumours. Here we report on a TTF-1 expressing mixed endocrine-exocrine carcinoma of the common bile duct in a patient with pulmonary nodules that did not appear to be neoplastic. TTF-1 positivity in pulmonary and extrapulmonary neuroendocrine tumours is reviewed, and we conclude that TTF-1 expression in neuroendocrine tumours of the small-cell type are not uncommon at extrapulmonary locations. Therefore, immunohistochemistry for TTF-1 in such tumours should be interpreted with caution.

• Authors: Laurine Verset, Marianna Arvanitakis, Patricia Loi, Jean Closset, Myriam Delhaye, Myriam Remmelink, Pieter Demetter
• Journal: World journal of gastrointestinal oncology (World J Gastrointest Oncol) Vol. 3 Issue 10 Pg. 144-7 (Oct 15 2011) ISSN: 1948-5204 [Electronic] China
• PMID: 22046491 (Publication Type: Journal Article)