Neuroendocrine Carcinoma in a Young Male

Abstract

Purpose: A 30 year old male with a medical history significant for hypertension and hemorrhoids presented with complaints of intermittent low-grade hematochezia after bowel movements over the last several months. He had no other symptoms such as abdominal pain or weight loss, and his family and social histories were unremarkable. Colonoscopy was performed and revealed internal hemorrhoids and a 2 mm nodule in the rectum that was biopsied and completely removed during the procedure. Pathology of the nodule revealed a neuroendocrine carcinoma, with positive immunostaining for synaptophysin, chromogranin and CD56. Subsequent metastatic workup, including PET scan and surgical evaluation of the rectum with local excision of the involved area, were negative for malignancy. At follow up four months later, the patient no longer reported blood with bowel movements and remained otherwise asymptomatic. Conclusion: Neuroendocrine cells are widely distributed throughout the body; neoplasms composed of these types of cells can occur at many sites and may display varying biologic behavior ranging from indolent (e.g., most carcinoid tumors) to aggressive (such as high-grade neuroendocrine carcinomas). Colorectal neuroendocrine carcinomas are extremely rare, with a reported incidence of 0.6 percent of all colorectal malignancies in a recent study. Pathologically, these tumors are usually poorly differentiated carcinomas with a high mitotic rate and foci of necrosis that show features of neuroendocrine differentiation by light microscopy. Generally speaking, neuroendocrine carcinomas carry a poor prognosis (with a median survival of 10.4 months) due to the fact that most patients already have metastatic disease when the diagnosis is made. Our patient, on the other hand, likely has an excellent prognosis owing to the fact that his tumor was detected (albeit incidentally) and treated at a very early stage, well before its potential for harm could be realized.