Jungsuk An1, Sanghui Park, Sun Hee Sung, Min-Sun Cho, Seung Cheol Kim. 1. Dept of Pathology, Ewha Womans University School of Medicine, 911-1 Mok-dong, Yangcheon-gu, Seoul, 158-710, Republic of Korea; spark0430@ewha.ac.kr; or to Dr Kim: Dept of Obstetrics and Gynecology, Ewha Womans University School of Medicine, 911-1 Mok-dong, Yangcheon-gu, Seoul, 158-710, Republic of Korea; onco@ewha.ac.kr.
Abstract
OBJECTIVES: Our study examines thyroid transcription factor 1 (TTF-1) expression in 40 primary adenoid cystic carcinomas (ACCs) arising in various sites and compares TTF-1 expression between primary and metastatic ACCs in 12 cases with distant metastases. METHODS: Forty patients with ACCs, including 12 pairs of primary and metastatic ACCs, were evaluated for the immunohistochemical expression of TTF-1 (clone SPT24). In addition, 10 metastatic ACCs to the lung were tested on napsin A and a different TTF-1 antibody (clone 8G7G3) for further evaluation. RESULTS: No primary ACCs showed TTF-1 immunoreactivity (clone SPT24). TTF-1 was positive in five (41.7%) of 12 metastatic ACCs; all five cases were found only in the lung and comprised five (50.0%) of 10 cases. In all positive cases, staining was focal and detected only in the cribriform histologic subtype. Staining patterns using both antibodies (both SPT24 and 8G7G3) were very similar, and TTF-1-positive tumor cells were also positive for napsin A. Extrapulmonary ACCs were all negative for TTF-1 regardless of origination and metastasis. CONCLUSIONS: TTF-1- and napsin A-positive ACCs in the lung should not be considered primary ACCs because TTF-1 and napsin A can be expressed in metastatic ACCs of the lung.
OBJECTIVES: Our study examines thyroid transcription factor 1 (TTF-1) expression in 40 primary adenoid cystic carcinomas (ACCs) arising in various sites and compares TTF-1 expression between primary and metastatic ACCs in 12 cases with distant metastases. METHODS: Forty patients with ACCs, including 12 pairs of primary and metastatic ACCs, were evaluated for the immunohistochemical expression of TTF-1 (clone SPT24). In addition, 10 metastatic ACCs to the lung were tested on napsin A and a different TTF-1 antibody (clone 8G7G3) for further evaluation. RESULTS: No primary ACCs showed TTF-1 immunoreactivity (clone SPT24). TTF-1 was positive in five (41.7%) of 12 metastatic ACCs; all five cases were found only in the lung and comprised five (50.0%) of 10 cases. In all positive cases, staining was focal and detected only in the cribriform histologic subtype. Staining patterns using both antibodies (both SPT24 and 8G7G3) were very similar, and TTF-1-positive tumor cells were also positive for napsin A. Extrapulmonary ACCs were all negative for TTF-1 regardless of origination and metastasis. CONCLUSIONS:TTF-1- and napsin A-positive ACCs in the lung should not be considered primary ACCs because TTF-1 and napsin A can be expressed in metastatic ACCs of the lung.