Schwannomas are mesenchymal tumors that are characteristically benign and slow growing, which originate from any nerve with Schwann cell sheath. Gastrointestinal schwannomas are rare with distinct morphologic features as compared to schwannomas of soft tissue or central nervous system. A 77-year-old male patient was diagnosed with gastrointestinal stromal tumor based on radiological findings and clinical impression when he presented with worsening abdominal discomfort and pain. He underwent distal gastrectomy however histopathological examination of the tumour revealed schwannoma. This case report presents a rare case of a symptomatic gastric schwannoma, whose definitive diagnosis was established by histopathological and immunohistochemical findings postoperatively.
Gastric duplication cyst (GDC) is a rare congenital malformation of the gastrointestinal (GI) tract. Despite being benign in the entity, its complications vary from an asymptomatic abdominal mass to fulminant or massive GI bleeding. A 28-year-old lady presented with unexplained GI haemorrhage, in which the upper endoscopy showed a classic feature of GI stromal tumour. The preoperative diagnosis was also confirmed by the computed tomography. She subsequently underwent surgical resection and the final histopathology was consistent with a benign entity of GDC.
Gastrointestinal stromal tumour (GIST) is a common mesenchymal tumour arising in the gastrointestinal tract, but not frequently encountered in the rectum. Herein, we describe a case of a rectal GIST which mimicked histomorphological features of a schwannoma; thus, making intraoperative frozen section evaluation challenging. Although subsequent immunohistochemistry and molecular findings readily confirmed the diagnosis of a GIST, we wish to draw attention to three clues that will help the pathologist steer clear of this potential diagnostic pitfall. One, GISTs are relatively more common than schwannomas in the rectum. Two, schwannomas usually have very little mitoses. Three, rectal GISTs commonly exhibit nuclear palisades. We also discuss the diagnostic, prognostic and therapeutic functions of immunohistochemical and molecular investigations. As the surgical intent for rectal GISTs is for en-bloc excision with wide margins, we surmise that the intraoperative consult should include GIST as a possible differential diagnosis for rectal mesenchymal tumours. In view of the potential for neoadjuvant treatment with imatinib before surgical excision to preserve sphincter function, a multidisciplinary approach is recommended for establishing most effective treatment strategy in these rare complex cases.
Gastrointestinal stromal tumour (GIST) is a rare but most common mesenchymal tumour in the gastrointestinal tract. Although GIST research has been carried out extensively worldwide, it has yet to be studied in Malaysia. To establish the immunohistochemical expression pattern of CD117 (c-KIT), CD34, S-100 and Desmin, the incidence of c-KIT and PDGFRA genes mutation in GISTs, and correlate it with clinicopathological parameters. Eleven clinically diagnosed GISTs were stained for CD117, CD34, Desmin and S-100 protein by immunohistochemical technique, and c-KITand PDGFRA gene mutations were studied by PCR-CSGE-DNA sequencing method. All GISTs (7 cases) stain positive for CD117, and co-expressed CD34. None of these cases express Desmin, and only one expressed S-100 protein focally. Fifty-seven percent (4/7 cases) of GIST harboured mutations at exon 11 of c-KIT gene, and they were all high risk and malignant cases. No mutation was detected at exons 9, 13 and 17 of KIT gene, and exons 12 and 18 of PDGFRA gene. Immunohistochemistry using a panel of antibodies shows consistent pattern of CD117 and CD34 expression in GIST, and mutational study may be a useful prognostic marker for kinase inhibitor treatment of GIST.