Posttransplant epithelioid inflammatory myofibroblastic sarcoma: A case report

Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is a rare entity and a novel variant of inflammatory myofibroblastic tumor (IMT), usually seen in children and nonsmoking young adults. Their occurrence in a posttransplant setting is still rare. These tumors are characterized by prominent epithelioid morphology, large histiocytoid “Reed Sternberg”-like cell, unique pattern of ALK immuno-reactivity, and aggressive clinical behavior. Their etiology and metastatic potential is controversial. In a post-transplant setting, many factors such as trauma, infections with EBV, HIV, Hepatitis C, mycobacteria, fungus, and chemotherapy-induced immunosuppression have been implicated in their etiology. We present the case of a 2-year-old female child who developed multiple omental and mesenteric tumor nodules, 8 months post liver transplant for progressive familial intrahepatic cholestasis (PFIC). Following a histopathological diagnosis of “mesenchymal neoplasm of possible malignant nature” on a trucut biopsy and frozen section, tumor debulking was performed. A final histological diagnosis of EMIS was made on the completely resected tumor. The patient remains in remission nearly 7 months after presentation, without any follow-up systemic chemotherapy. IMT after a solid organ transplant is rare, only 5 cases have been reported in the literature until now. Similar phenomenon has also been noted with hematopoietic stem cell transplant. However, to our knowledge, this case of EMIS in a post liver transplant patient is first of its kind.

Clinicopathologic characteristics of intra-abdominal EIMS and review of the literature / 临床与实验病理学杂志

Purpose To explore the clinicopathologic characteristics, immunophenotype, diagnosis and differential diagnosis, molecu-lar genetic feature, treatments and prognosis of intra-abdominal EIMS. Methods Two cases of intra-abdominal EIMS were studied with clinical manifestations, histology and immunohistochemical staining, and its clinical and pathological findings were further ana-lyzed with review of the literature. Results Case 1 was a 15-year-olds male and case 2 was a 21-year-olds female both of whom pres-ented with abdominal pain. Two patients were treated by surgical excision. Microscopically the tumor consisted of two different histolog-ical types, one of which was of high cell density and the other with low cell density and myxoid stroma. Both of these areas contained inflammatory cells, mainly neutrophils with few lymphocytes and plasmocytes. Tumor cells had an epithelioid phenotype with round nu-clei and small nucleoli, various nuclear atypia and mitotic figures were also found, which consistented with the diagnosis of epithelioid inflammatory myofibroblastic sarcoma. Immunohistochemical analysis revealed that the tumor cells were positive for ALK, vimentin, desmin, and CK(AE1/AE3) (focal), and were negative for Calretinin, CD30, CD31, CD33, SMA, HHF35, Myogenin, S-100, HMB-45, CD20, CD79a, CD3, CD5, CD45 and CD68. ALK rearrangement was identified in both cases by FISH using ALK break-a-part probe. Conclusions As an extremely rare tumor, the distinguishing between epithelioid inflammatory myofibroblastic sarcoma and conventional inflammatory myofibroblastic tumor is important. ALK inhibitors are theoretically useful for treating these tumors.