Primary small cell carcinoma of the esophagus with achalasia in a patient in whom pro-gastrin-releasing peptide and neuron-specific enolase levels reflected the clinical course during chemotherapy

We report a case of primary small cell carcinoma of the esophagus in a patient with achalasia in whom pro-gastrin-releasing peptide (ProGRP) and neuron-specific enolase (NSE) levels were measured. Although chemotherapy markedly reduced the size of the primary tumor and lymph node metastases, it had no effect on liver metastases. The tumor marker levels decreased after chemotherapy as the primary tumor and lymph node metastases decreased in size, and they increased as the liver metastases enlarged. However, there was a discrepancy between the levels of ProGRP and NSE during the patient's clinical course. We demonstrate the usefulness of measuring ProGRP and NSE levels to assess the effect of chemotherapy in patients with esophageal small cell carcinoma.