Lesions originating within the retrorectal space: a diverse group requiring individualized evaluation and surgery

Tumors occurring within the retrorectal space are rare and their low incidence has led to a paucity of literature regarding them.

Adult patients with retrorectal tumors managed at this institution from 1981-2011 were identified. A retrospective chart review was conducted to obtain relevant data.

Retrorectal tumors were identified in 87 patients (67 female) with median age at diagnosis of 44 years (19-88), and median follow-up 8 months (0.1-225). Of the 25 different histologic tumors diagnosed, hamartomas were most common (32 %; n = 28) followed by epidermal cysts (11 %; n = 10), and teratomas (10 %; n = 9). Twenty-six percent (23/87) of all tumors were malignant. CT scans were obtained in 84 % (73/87) of patients, MRI in 59 % (51/87), and TRUS in 16 % (14/87). While 74 % (64/87) of tumors were at or below the S4 level, operative approach was strictly posterior in 73 % (46/63) of these tumors. Twenty-eight percent (24/87) of patients underwent diagnostic biopsy with no reported biopsy site recurrence. Thirty percent (7/23) of resected malignant (all recurrences: distant) and eleven percent (7/64) of benign tumors (all recurrences: local) recurred. Survival was 70 % (16/23) for malignant tumors and 98 % (63/64) for benign tumors.

Retrorectal tumors remain heterogeneous and a diagnostic challenge. Pre-operative imaging may help guide surgeons; however, malignancy portends worse outcomes. Despite preoperative biopsy site recurrence concerns, no patient in this study had biopsy site recurrence. As their natural history remains unclear, more studies are necessary to further characterize their behavior.