Gastrointestinal stromal tumor of the small bowel complicated by torsion: A case report

Abstract

Introduction: Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors that originate from the gastrointestinal tract wall. Approximately 20-30 % of GISTs originate from the small intestine. GISTs of the small intestine generally present with a palpable mass, distention, and abdominal pain and may exhibit acute abdomen at the onset. Herein, we describe a rare case of a pedunculated GIST of the small intestine complicated by torsion.

Presentation of case: A 69-year-old woman presented with lower abdominal pain. Abdominal contrast-enhanced computed tomography showed a 73 × 62 × 57-mm³ tumor in the pelvic cavity with enhanced margins and reduced contrast. It was presumed that the tumor had caused hemorrhagic infarction. Emergency laparotomy was performed, and the pedunculated tumor was found to be twisted 360° clockwise at the pedicle with hemorrhage and necrosis due to torsion. We performed partial resection of the small intestine including the tumor. Histopathological examination revealed tightly arranged spindle-shaped cells with hemorrhage, congestion, and inflammatory cell infiltration. Immunohistochemical staining showed positivity for CD34, CD117, and DOG1.

Conclusions: Torsion of a pedunculated small intestine GIST, although very rare, requires emergency surgery and should be recognized as a cause of acute abdomen in patients with GIST. Immediate surgery is mandatory if torsion of a small intestinal GIST is suspected because the GIST or intestine may become necrotic owing to hemorrhagic infarction.

Keywords: Acute abdomen; Case report; Gastrointestinal stromal tumor; Small intestine; Torsion.

Fig. 1

Abdominal ultrasonography findings. (a) Abdominal ultrasonography shows a 73 × 52 mm² tumor in the pelvis, which has a mixture of high and low echo densities. (b) No blood flow is observed inside the tumor on color Doppler ultrasonography.

Fig. 2

Computed tomography findings. (a) Abdominal computed tomography (CT) shows a 73 × 62 × 57 mm³ low-density tumor in the pelvic cavity. (b) Contrast-enhanced CT shows an enhanced tumor margin but no contrast effect inside it.

Fig. 3

Intraoperative findings. (a, b) The pedunculated tumor originates from the contralateral mesentery of the small intestine, 190 cm from the ligament of Treitz on the anal side and 250 cm from the ileocecal valve on the oral side; it is twisted 360° at the pedicle (arrow) and shows features suggestive of hemorrhagic necrosis. No torsion was observed in the small intestine, to which the tumor was attached, and no evidence of intestinal obstruction, bleeding, or necrosis was present. There was no evidence of tumor infiltration into surrounding organs and lymph node metastasis in the small mesentery.

Fig. 4

Gross findings after formalin fixation. (a). The 75 × 55 × 45-cm³ tumor is well-defined, reddish-brown, uneven, and elastically hard. (b)The cut surface shows a gray/red solid tumor with phyllodes and internally, the tumor is heterogeneous and solid after formalin fixative is applied.

Fig. 5

Histopathological findings. 1) Hematoxylin and eosin staining showing tightly arranged spindle-shaped cells (b, c) that are accompanied by hemorrhage, congestion, and inflammatory cell infiltration (a). The scale bars in (a), (b), and (c) indicate 500 μm, 200 μm, and 50 μm, respectively. 2) Immunohistochemical analysis showing tumor cells stained positive for (d) CD34, (e) CD117 (C-kit), and (f) DOG1; weakly positive for (g) α-smooth muscle actin; and negative for (h) S200 and (i) desmin. The scale bar indicates 100 μm.