Frequent Presence of Lymphovascular Invasion in Small Rectal Neuroendocrine Tumors on Immunohistochemical Analysis

Rectal neuroendocrine tumor developing lateral lymph node metastasis after curative resection: a case report

Background

Among gastrointestinal neuroendocrine tumors (NETs), rectal NETs account for about one-third of all tumors. Despite the occasional observation of lateral lymph node metastasis in patients with rectal NETs, lateral lymph node recurrence is rare. We present a rare case of lateral lymph node recurrence after curative resection of a rectal NET.

Case presentation

A 55-year-old man presented with fecal occult blood and colonoscopy revealed a mass in the distal rectum. Systematic computed tomography scan showed no evidence of regional lymph node or distant metastasis. The patient underwent laparoscopic intersphincteric resection and D2 lymph node dissection with diverting stoma. Diverting stoma closure was performed 6 months after the initial operation. Pathological diagnosis was NET of the rectum, grade 2, T1b, N0, Stage I without lymphovascular invasion. At 54 months after the surgery, recurrence in a left lateral lymph node was suspected and lymph node dissection was performed. The pathological diagnosis of the specimen was consistent with lateral lymph node metastasis of a recurrent rectal NET. To our best knowledge, there are no case reports in English of lateral lymph node recurrence after curative resection of a rectal NET, grade 2, T1b, N0, Stage I without lymphovascular invasion.

Conclusion

Considering that patients with lateral lymph node metastasis have worse survival than those without metastasis in rectal cancer, if complete resection of the tumor can be achieved for lateral lymph node recurrence, surgery may be an important option in the strategy to treat this condition.