PT  - JOURNAL ARTICLE
AU  - Anna Fen-Yau Li
AU  - Alice Chia-Heng Li
AU  - Chih-Yi Hsu
AU  - Win-Yin Li
AU  - Han-Shui Hsu
AU  - Jeou-Yuan Chen
TI  - Small cell carcinomas in gastrointestinal tract: immunohistochemical and clinicopathological features
AID  - 10.1136/jcp.2010.077024
DP  - 2010 Jul 01
TA  - Journal of Clinical Pathology
PG  - 620--625
VI  - 63
IP  - 7
4099  - http://jcp.bmj.com/content/63/7/620.short
4100  - http://jcp.bmj.com/content/63/7/620.full
SO  - J Clin Pathol2010 Jul 01; 63
AB  - Aims To test the incidence of the expression of the immunohistochemical markers that aid diagnosis of gastrointestinal tract small cell carcinoma (GI-SmCC) and to evaluate the incidence of mixed endocrine–exocrine carcinomas in GI-SmCC.Methods Immunohistochemical studies of three antibodies against epithelial markers (CK8, AE1/AE3, EMA), four neuroendocrine differentiation markers (synaptophysin (Syn), neuron specific enolase (NSE), neuronal cell adhesion molecules (CD56), chromogranin A (CgA)), and a transcription factor (thyroid transcription factor 1 (TTF-1)) were performed. The incidence of non-endocrine carcinoma component was evaluated in 42 GI-SmCCs (11 in the oesophagus, 15 in the stomach, 15 in the colon, and 1 in the small intestine).Results The percentages of GI-SmCC with positive immunoreactivity were: CK8 92.9%, AE1/AE3 76.2%, EMA 71.4%, Syn 100%, NSE 100%, CD56 90.5%, CgA 61.9%, TTF-1 21.4%. The low molecular weight cytokeratin CK8 is more commonly expressed in GI-SmCC than is the expression of AE1/AE3 or EMA. Synaptophysin and NSE are expressed in all GI-SmCCs studied. Non-endocrine carcinoma components were demonstrated in 8 patients (4 in the oesophagus and 4 in the stomach).Conclusion In detecting GI-SmCC, epithelial marker CK8 is more sensitive than AE1/AE3 or EMA, and neuroendocrine differentiation markers synaptophysin and NSE are the most useful markers. TTF-1 positivity is not uncommon in GI-SmCC, but cases with negative TTF-1 staining may indicate an extra-pulmonary primary. Non-endocrine carcinoma components were demonstrated in about 30% of oesophagus and stomach SmCC; the neoplasms should be diagnosed as mixed endocrine–exocrine carcinoma.