Presacral Ganglioneuroma: Diagnostic Considerations and Therapeutic Strategy
A 35-year-old man presented to our hospital due to mild lower left abdominal pain lasting for 2 weeks. He reported one episode of uncomplicated diverticulitis 5 years ago, and his past medical history was unremarkable. He did not suffer from back pain or other neurologic symptoms and was physically active. Changes in bowel habits were not present. Routine blood tests, serum tumor markers (carcinoembryonic antigen, cancer antigen 19-9, and cancer antigen 125), α-fetoprotein and plasma and urine catecholamines were within normal range.\nAbdominal ultrasonography incidentally revealed a huge solid pelvic mass, with well-defined borders. Abdominal computed tomography (CT) confirmed the presence of a well-circumscribed solid tumor in the presacral region, measuring 10 × 8.5 cm in size and presenting smooth edges and no calcifications (fig. ). Pelvic magnetic resonance imaging (MRI) confirmed the extension of the lesion from the S2 level to the coccyx (fig. ). The mass had low signal intensity on T1-weighted images and heterogeneous high signal intensity on T2-weighted images with no intraspinal or rectal extension. In addition, we were able to demonstrate by T2-weighted images that it was a compartmentalized solid tumor with cystic components (fig. ). Colonoscopy examination revealed the presence of diverticulum in the sigmoid colon without inflammation and tumor involvement of the rectum.\nThe patient was submitted to surgical laparotomy without a preoperative fine-needle biopsy (FNA). An abdominal approach was used with the patient in the modified Lloyd-Davies position. The lesion was approached transperitoneally with presacral mobilization of the rectum, and complete tumor resection with free surgical margins was achieved. The specimen included a tumor of 10 × 8.5 × 4 cm in size, surrounded by a thin fibrous capsule, with elastic consistency, a compact form, and a grayish and partially brownish color.\nAfter microscopic examination and immunohistochemical study, the diagnosis of mature GN was established. The neoplasm contained mature ganglion cells and Schwann cells together with collagen (fig. ). Ganglion cells were distributed diffusely throughout the tumor or arranged in small clusters. There was no neuroblastomatous component. Mitoses were very rare. The immunophenotype of the neoplasm was as follows: synaptophysin (+), neuron-specific enolase (+), S-100 (+), neurofilaments (+), vasoactive intestinal polypeptide (+), protein 27 (+), myeline basic protein (–), and epithelial membrane antigen (–). The index of cellular proliferation ki-67 was <1%.\nThe patient had an uneventful recovery and was discharged on the 12th postoperative day. Repeat MRI at 12 and 24 months after surgery and neurologic examination were unremarkable.