Composite neuroendocrine carcinoma and squamous cell carcinoma with regional lymph node metastasis: a case report

Neuroendocrine cell carcinoma is a rare variant of esophageal carcinoma. The characteristic clinical features and diagnosis of superficial neuroendocrine cell carcinoma remain to be established. We report a rare case of superficial coexistence of neuroendocrine cell carcinoma with squamous cell carcinoma treated by endoscopic submucosal dissection, and regional lymph node metastasis was detected after additional surgical treatment. A 77-year-old Japanese man with esophageal squamous cell carcinoma received endoscopic submucosal dissection in en-bloc resection. Histopathological findings showed that lymphovascular invasion by the neuroendocrine cell carcinoma component occurred in the deep part of the muscularis mucosa. Regional lymph node metastasis was identified after additional surgical treatment. After surgical treatment, our patient received chemotherapy consisting of etoposide and carboplatin for 3 months. He is alive and shows no sign of disease recurrence 12 months after surgery. This case report highlights the fact that even if neuroendocrine cell carcinoma is small and limited to superficial, the tumor has the potential for metastasis if lymphovascular invasion by the neuroendocrine cell carcinoma component occurs. In addition, this case indicates the necessity of close follow-up of small neuroendocrine cell carcinoma after treatment.