Perirectal Extragastrointestinal Stromal Tumor: An Unusual Presentation

Extragastrointestinal Stromal Tumor Mimicking Appendicitis: A Case Study

BACKGROUND Extragastrointestinal stromal tumors (E-GISTs) are a rare subtype of gastrointestinal stromal tumors (GISTs) that develop outside of the gastrointestinal tract from interstitial cells of Cajal, exhibiting specific markers such as CD117 and DOG1. These tumors often present diagnostic challenges, particularly when their clinical manifestations mimic other abdominal conditions, such as acute appendicitis. CASE REPORT A 75-year-old male patient with a history of multiple comorbidities presented to the Emergency Department with symptoms of chronic pain in the right lower quadrant. Imaging studies, including computed tomography scans, revealed a large heterogeneous density mass measuring 11.3×9.2 cm in the right lower quadrant and a dilated appendix with wall thickening. Subsequent surgical resection with right hemicolectomy and primary anastomosis was performed, and postoperative considerations included adjuvant therapy with imatinib, due to spindle cell morphology and high mitotic activity. Histopathological examination and immunohistochemical staining confirmed the diagnosis, showing positive CD117, DOG1, Bcl-2, D2-40, and WT1 markers. CONCLUSIONS This case report aims to highlight the complexities in diagnosing E-GISTs with atypical presentations and emphasizes the critical role of comprehensive imaging and histopathological assessments in achieving an accurate diagnosis and guiding appropriate management strategies. The successful diagnosis and management highlight the critical role of imaging modalities and immunohistochemical analysis in guiding treatment decisions, while postoperative care, including targeted therapy, is crucial for reducing the risk of recurrence and improving patient outcomes. Future research should focus on optimizing postoperative management strategies and investigating the potential of intraoperative biopsies for tumors abutting adjacent structures.

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.

Extra-Gastrointestinal Stromal Tumor (EGIST) in the Pelvis Mimicking Retroperitoneal Sarcoma

Extra-gastrointestinal stromal tumors (EGISTs) are rare mesenchymal tumors accounting for less than 1% of total gastrointestinal tumors. They tend to be aggressive and have a poor prognosis. Unfortunately, there is a lack of data or controversial data due to its scarcity. Therefore, we report a case of pelvic EGIST misdiagnosed as retroperitoneal sarcoma. We opted for surgical management followed by adjuvant oral chemotherapy with imatinib.