폐의 원발성 반지세포암종은 전이성 반지세포암종 보다는 매우 드문 질환이다. 저자들은 면역조직염색법의 도움을 받아 원발성 반지세포 폐암종으로 진단된 1례를 경험하였기에 문헐고찰과 함께 보고한다. 본 증례를 통하여 반지세포암종이 폐에서 관찰되었을 때 폐 외에 원발부위가 없다면 원발성 반지세포 폐암종일 가능성을 의심하고 TTF-1 과 CK7 및 CK20 면역염색을 시행하면 진단에 도움을 받을 수 있다.
Signet ring cell carcinoma (SRCC) of the lung is a rare variant of pulmonary adenocarcinoma. Because the majority of SRCCs in the lung are metastatic tumors from stomach, colon, or breast. The differential diagnosis of primary SRCC from metastatic SRCC is important but may be problematic. Recently, immunohistochemical studies are known to be valuable in determining primary sites of SRCC. Herein, we present a case of primary signet ring cell carcinoma of the lung in a 67-year-old man. Even though radiographic findings of our case were more suggestive of metastatic orgin of SRCC in the lung, we could finally conclude that lung was the primary site of SRCC with the help of immunohistochemical studies (positive TTF-1 and CK7, and negative CK 20) and other diagnostic work up.
