TTF-1 Expression in Rectal Adenocarcinoma: A Case Report and Review of the Literature

Thyroid transcription factor 1 (TTF-1) is considered a highly sensitive and specific marker for primary lung adenocarcinoma. However, in recent years retrospective studies of tumor samples have confirmed that, although rare, TTF-1 can also be expressed in colorectal adenocarcinoma. There are a few case reports of patients with TTF-1-positive colon adenocarcinoma in the medical literature but none of TTF-1-positive rectal adenocarcinoma. Here, we present a case of rectal adenocarcinoma with lung metastasis found to be TTF-1 positive on immunohistochemistry. A review and discussion of the available literature is also included.