CASE REPORT ON RARE OUTCOME OF A RETROPERITONEAL MASS: MANAGEMENT CHALLENGES AND LESSONS LEARNT

Background. Gastrointestinal stromal tumours (GIST) are non-epithelial mesenchymal solid neoplasm with varied presentation. The study reports the case of a retroperitoneal GIST in a 21‑year‑old male presented with an abdominal lump for six months. The lesion was initially thought to be a retroperitoneal sarcoma. Exploratory laparotomy revealed an abdominopelvic mass covering the entire right side of abdomen and pelvis. The tumour was adherent to the terminal ileum and ascending colon. There were dense adhesions between the retroperitoneum with involvement of the middle third of the right ureter. The tumour was resected with right hemicolectomy with ileotransverse anastomosis. Post-operative histopathology revealed it as high-grade spindle cell type GIST. The patient is presently on post-operative chemotherapy with Imatinib mesylate. Objective. Atypical presentations of GIST are seldom discussed but frequently encountered in clinical practice. This article depicts different challenges the surgeon has to face while diagnosing such atypical entity. Methods. Case report of atypical GIST presenting as retroperitoneal lump. Results. The patient underwent surgical resection and is presently on post-operative chemotherapy with good overall outcome for a one year follow up. Conclusions. GISTs presenting as retroperitoneal lumps are very rare, they should be considered in their differential diagnosis of an atypical retroperitoneal mass.