Two Cases of Succinate Dehydrogenase-Deficient Juvenile Gastric Gastrointestinal Stromal Tumor

Abstract

Introduction: SDH-deficient GIST is a part of WT GIST that constitutes approximately 10% of gastric GISTs and has no mutation of proto-oncogene receptor tyrosine kinase or PDGFR-α. In this paper, we present 2 cases of juvenile WT gastric GIST with SDH deficiency: a woman who underwent initial surgical treatment in junior high school and subsequently underwent 2 surgical treatments, and a man with lymph node metastasis who underwent distal gastrectomy with lymphadenectomy.

Case presentation: The 1st case was a woman who was diagnosed with gastric GIST and underwent distal gastrectomy at another institution when she was in junior high school. And she was diagnosed with gastric GIST again at our institution after a close examination for anemia and underwent laparoscopic partial gastrectomy. Two years ago, a GIS revealed another multiple gastric GIST in the remnant stomach, and a total remnant gastrectomy with lymphadenectomy was performed. The 2nd case was a man who was diagnosed with gastric GIST after a thorough examination of the cause of anemia. A 30-mm gastric GIST was found in the antrum, and a distal gastrectomy with lymphadenectomy was performed in this case as well. Pathological findings showed a metastatic lymph node in the subpyloric region.

Conclusions: Lymphadenectomy may be needed to improve the prognosis of juvenile GIST patients without distant metastasis because SDH-deficient GIST is more frequent in the younger generation, and SDH-deficient GIST has a higher frequency of lymph node metastasis.

Keywords: SDH-deficient GIST; juvenile; lymph node metastasis.

Fig. 1. Representative images from abdominal examinations. (A) The upper gastrointestinal endoscopy revealed a submucosal tumor on the lesser curvature wall of the remnant stomach. (B) The endoscopic ultrasound showed 3 hypoechoic masses with a maximum diameter of 16 mm, which were suspected to be submucosal tumors.

Fig. 2. Pathological findings. (A) Gross findings of the resected remnant stomach. Four masses were seen on the lesser curvature side of the remnant stomach. (B and C) Microscopic findings showed spindle-shaped and epithelioid cells (original magnification ×200). (D) Positive staining with succinate dehydrogenase subunit A immunostaining (original magnification ×20). (E) Loss of staining with succinate dehydrogenase subunit B immunostaining (original magnification ×20). (F) The pathological findings of the 2nd surgery (original magnification ×20).

Fig. 3. Representative images from abdominal examinations. (A) The upper gastrointestinal endoscopy showed a submucosal tumor on the posterior wall of the antrum. (B) The endoscopic ultrasound showed a hypoechoic mass in the 4th layer with clear borders but multifocal and somewhat heterogeneous interior. (C) Computed tomography showed a mass with contrast effect in the antrum. No clearly swelling lymph nodes were seen.

Fig. 4. Pathological findings. (A) Gross findings of the resected sample. Two masses were seen on the posterior wall of the antrum. (B and C) Microscopic findings showed spindle-shaped and epithelioid cells (original magnification ×200). (D) Microscopic findings showed epithelioid cells in lymph node (original magnification ×200). (E and F) Loss of staining with succinate dehydrogenase subunit A and succinate dehydrogenase subunit B immunostaining (original magnification ×200).