Schwannoma of the sigmoid colon

Abstract

Colonic schwannomas are very rare gastrointestinal tumours originating from Schwann cells, which form the neural sheath. Primary schwannomas of the lower gastrointestinal tract are very rare and usually benign in nature. However, if they are not surgically removed, malign degeneration can occur. We report a case of a 79-year-old woman who presented to our clinic with rectal bleeding and constipation. She underwent a lower gastrointestinal tract endoscopy. A mass subtotally obstructing the lumen of the sigmoid colon was seen and biopsies were taken. Histopathological examination indicated a suspicion of gastrointestinal tumour and the patient underwent sigmoid colon resection after preoperative evaluation by laboratory analysis, abdominal ultrasonography and CT. Her postoperative course was uneventful and she was discharged on the fifth day for outpatient control. The histopathology report revealed schwannoma of the sigmoid colon. This was a case of schwannoma of the sigmoid colon that was successfully treated with total resection.

Figure 1

Abdominal CT findings revealed a round polypoid lesion with homogeneous low attenuation inside the sigmoid colon with adjacent wall thickening.

Figure 2

Macroscopic appearance of the tumour at the sigmoid colon.

Figure 3

Schwannoma area at the right side showing diffuse S100 positivity. S100×2.

Figure 4

Rosette formation; schwannoma cells expressing S100 and vimentin positivity. S100×40.