Rectal Granular Cell Carcinoma Requiring Abdominoperineal Resection

Background Granular cell tumors, derived from neural crest cells, are rare tumors infrequently located in the colon or rectum. We will discuss a patient with a rectal granular cell tumor invading the anal sphincters requiring an abdominoperineal resection. Methods A 56-year-old male, with anal pain, was found to have a perirectal mass. Pathology from ultrasound-guided transrectal biopsy demonstrated low grade granular cell tumor. The patient underwent a laparoscopic abdominoperineal resection with perineum reconstruction. Results Pathology demonstrated a granular cell tumor of 4.5 centimeters with tumor invasion of the anal sphincters. Surgical margins were free of neoplasm. Discussion This is the only documented case of a colorectal granular cell tumor that has required an abdominoperineal resection. On histology, it was considered low grade but its behavior was more consistent with a malignant process. Additional research on malignant granular cell tumors is necessary to help improve treatment options, prevent recurrence, and improve overall survival. His medical course will be followed for disease progression or metastasis.