Inflammatory Myofibroblastic Tumor of the Esophagus and Stomach Successfully Treated With ALK Inhibitor in a Pediatric Patient: A Case Report and Concise Review of Literature.

An inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal neoplasm of borderline malignant potential. Nearly half of all IMTs have rearrangement of anaplastic lymphoma kinase (ALK) locus on chromosome 2p23 which can be treated with targeted therapy. Herein, we describe an unusual presentation of IMT involving an anatomical region rarely implicated in this disease process. A 15-year-old male patient came to the ER with dysphagia and coffee ground emesis. On esophagogastroscopy, a nodular luminal obstructing 30 × 50 mm mass in the lower esophagus was found, which was continuous with a large, partially circumferential gastric mass extending from the mid-body to the proximal antrum. Biopsies from esophageal and gastric masses revealed submucosal lesions composed of cytologically bland spindle and epithelioid cells, intermingled with inflammatory infiltrate, for which several immunohistochemical (IHC) stains were performed. The molecular study demonstrated ATIC::ALK fusion. Based on morphological, IHC, and molecular study findings, the diagnosis of ALK-positive IMT was rendered. Because surgical excision was deemed infeasible, the patient was started on ALK-inhibiting therapy with crizotinib. The patient responded well with no evidence of residual or recurrent disease on follow-up imaging or surveillance esophagogastroduodenoscopy. Crizotinib was ultimately discontinued after 10 months of therapy, and the patient continues to undergo surveillance imaging for monitoring of disease burden.

Dedifferentiated Liposarcoma: A Rare Case Report of Retroperitoneal Myxoid Soft Tissue Tumour with Diagnostic Dilemma.

Background: The retroperitoneum can host a wide spectrum of soft tissue lesions. These tumours pose a challenge to the pathologist as the morphology is not of much help and immunohistochemistry becomes a necessity. Case report: Sixty years old male presented with 2 months history of abdominal lump, pain and dyspepsia. The MRI revealed a heterogeneous mass in the retroperitoneum involving right para spinal muscle, right iliac fossa and right perinephric region with destruction of right transverse process and erosion of adjacent L3 vertebra. Trucut biopsy of the mass was reported as fibroliposarcoma at an outside lab. Patient underwent a wide local excision. Grossly the tumour gave an impression of a liposarcoma but the microscopy showed areas of spindle cells, epitheloid cells, focal areas of ganglion like cells and large areas of myxoid change. IHC panel of S-100, SMA, caldesmon, myogenin, myoglobin and Alk-1 was negative. MDM2, CDK4 and p16 IHC came positive proving it to be a dedifferentiated liposarcoma. Conclusion: We report a curious case of retroperitoneal soft tissue tumour with complex morphology and IHC features diagnosed as dedifferentiated liposarcoma based on MDM2, CDK and p16 positivity.