Superficial primary small cell carcinoma of the esophagus: clinicopathological and immunohistochemical analysis of 15 cases.

Primary esophageal small cell carcinoma (PESCC) is a relatively rare and aggressive tumor with poor prognosis. Systemic spreading and metastasis often occur at diagnosis. Although 5-year survival rate of superficial squamous cell carcinoma of the esophagus can be 86.1%, 5-year survival rate of superficial PESCC is still relatively low. This study mainly retrospectively analyzed clinicopathological and immunohistochemical features of 15 cases of superficial PESCC in our hospital from 1990 to 2004, in order to find suitable diagnostic markers and applicable therapies for this disease. The records mainly included presenting symptoms, demographics, diagnostic method, histopathology, follow-up, and therapy. Immunohistochemical staining of chromogranin A (CgA), neuron-specific enolase (NSE), synaptophysin (Syn), neuronal cell adhesion molecules (CD56), thyroid transcription factor-1 (TTF-1), cytokeration 34betaE12 (CK34betaE12), cytokeratin (AE1/AE3), and cytokeratin 10/13 was performed. Incidence of superficial PESCC accounted for 4.8% of that of superficial carcinoma of the esophagus during the same period. Initial symptoms of all patients were dysphagia or accompanied with retrosternal pain and upper abdominal pain, and duration of these symptoms was 75 days averagely. Mean age of patients was 58.8 years old, and the male-to-female ratio was 2.75 : 1. Lesions were mainly located at middle thoracic esophagus. One, 2, and 5-year survival rates were 66.7, 33.3, and 6.7%, respectively. The median survival time was 19 months and mean survival time was 23.7 months after diagnosis. The percentages of PESCC samples with positive immunoreactivity were NSE 100%, Syn 100%, AE1/AE3 100%, CD56 93.3%, TTF-1 60%, CgA 53.3%, CK34betaE12 6.7%, and cytokeratin 10/13 0%, respectively. Our study suggested that PESCC was a rare and aggressive tumor with high malignancy. Superficial PESCC had rapid progression and poor prognosis compared with superficial squamous cell carcinoma of the esophagus at the same stage. The systemic therapy based on combination of postoperative chemotherapy and radiotherapy might be an effective approach for the treatment of superficial PESCC as a systemic disease. Higher proportion of positive labeling of NSE, Syn, AE1/AE3, CD56, TTF-1, and CgA in PESCC was valuably applied in diagnosis and differential diagnosis.