Extragastrointestinal stromal tumors with diffuse membranous distribution with bleeding:A case report

BACKGROUND Extragastrointestinal stromal tumors(EGIST)and gastrointestinal stromal tumors are of similar pathological type and form.Here we report a rare case of EGIST diffusely distributed in membranous tissue in abdominal cavity,the feature of which included diffuse tumors at membranous tissue in entire abdominal cavity and spontaneous bleeding of the tumors.CASE SUMMARY The patient was a 71-year man and hospitalized due to continuous pain at lower abdomen for more than 10 days.Upon physical examination,the patient had flat and tough abdomen with mild pressing pain at lower abdomen,no obvious abdominal mass was touchable,and shifting dullness was positive.Positron emission tomography-computed tomography(CT)showed that in his peritoneal cavity,there were multiple nodules of various sizes,seroperitoneum,multiple enlarged lymph nodes in abdominal/pelvic cavity and right external ilium as well as pulmonary nodules.Plain CT scanning at epigastrium/hypogastrium/pelvic cavity+enhanced three-dimensional reconstruction revealed multiple soft tissue nodules in abdominal/pelvic cavity,peritoneum and right groin.Tumor marker of carbohydrate antigen 125 was 808 U/mL,diffuse tuberous tumor was seen in abdominal/pelvic cavity during operation with hematocelia,and postoperative pathological examination confirmed EGIST.Imatinib was administered with better therapeutic effect.CONCLUSION Gene testing showed breast cancer susceptibility gene 1 interacting protein C-terminal helicase 1 and KIT genovariation,and the patient was treated with imatinib follow-up visit found that his clinical symptoms disappeared and the tumor load alleviated obviously via imageological examination.

Primary multiple extragastrointestinal stromal tumors of the omentum with different mutations of c-kit gene

The author reports a very rare case of sporadic primary multiple extragastrointestinal stromal tumors (EGISTs) of the omentum associated with different mutations of the exon 11 of the c-kit gene in a 75-year-old man with gastric cancer. During an operation for the cancer, two solid tumors (10 mm and 8 mm) were found in the omentum. Both tumors consisted of cellular spindle cells. Mitotic figures were two and three per 50 high power fields. The tumor cells were positive for KIT, CD34 and vimentin, but negative for desmin, S100 protein, α-smooth muscle actin and p53 protein. Ki67 labeling was 2% and 3%. The larger EGIST showed a deletion of codons 552-558 of exon 11 of the c-kit gene, while the smaller EGIST had a point mutation at codon 559 (GTT←GAT) in exon 11 of the c-kit gene. Exons 9, 13, and 17 of the c-kit gene, and exons 12 and 18 of the platelet derived growth factor receptor α genes showed no mutations. The case shows that sporadic multiple EGISTs can occur in the omentum.

Multiple malignant extragastrointestinal stromal tumors of the greater omentum and results of immunohistochemistry and mutation analysis:A case report

To report an extragastrointestinal stromal tumor （EGIST） that occurs outside the gastrointestinal tract and shows unique clinicopathologic and immunohistochemical features. In our case, we experienced multiple soft tissue tumors that originate primarily in the greater omentum, and in immunohistochemical analysis, the tumors showed features that correspond to malignant EGIST. Two large omental masses measured 15 cm×10 cm and 5 cm×4 cm sized and several small ovoid fragments were attached to small intestine, mesentery and peritoneum. On histologic findings, the masses were separated from small bowel serosa and had high mitotic count （115/50 HPFs）. In the results of immunohistochemical stains, the tumor showed CDl17 （c-kit） positive reactivity and high Ki-67 labeling index. On mutation analysis, the c-kit gene mutation was found in the juxtamembrane domain （exon 11）and it was heterozygote. Platelet-derived growth factor receptor （PDGFR） gene mutation was also found in the juxtamemembrane （exon 12） and it was polymorphism. From above findings, we proposed that there may be several mutational pathways to malignant EGIST, so further investigations could be needed to approach this unfavorable disease entity.

Extragastrointestinal stromal tumor presenting as a scrotal mass： an unusual case

We describe an unusual case of extragastrointestinal stromal tumor （EGIST） presenting as a scrotal mass. A 71- year-old man presented with a gradually enlarging scrotal mass with a 20-year duration. Physical examination re vealed a huge （as large as volleyball）, round, nontender mass occupying the whole scrotum, which was resected completely. Clinical and radiological findings did not comply with any other primary site disease. Under histological examination, the tumor showed a spindle cell pattern with low cellularity, absence of necrotic and mitotic features. Immunohistochemical anlaysis revealed the tumor reactive for CD117 and CD34, while negative for smooth muscle actin, desmin and S-100 protein. To our knowledge, this is the first reported case of an EGIST involving the scrotum.