epithelioid inflammatory myofibroblastic sarcoma
Definition: Epithelioid inflammatory myofibroblastic sarcoma is an aggressive intra-abdominal variant of inflammatory myofibroblastic tumor With nuclear membrane or perinuclear ALK. (#21164297#)
Inflammatory myofibroblastic tumor (IMT) is a mesenchymal neoplasm of intermediate biological potential, which may recur and rarely metastasize. Pathologic features do not correlate well with behavior.
Approximately 50% of conventional IMTs harbor ALK gene rearrangement and overexpress ALK, most showing diffuse cytoplasmic staining.
Rare IMTs with a distinct nuclear membrane or perinuclear pattern of ALK staining and epithelioid or round cell morphology have been reported. These cases pursued an aggressive clinical course, suggesting that such patterns may predict malignant behavior.
Unlike conventional IMT, abundant myxoid stroma and prominent neutrophils are common in epithelioid inflammatory myofibroblastic sarcoma. These tumors pursue an aggressive course with rapid local recurrences and are frequently fatal.
The designation "epithelioid inflammatory myofibroblastic sarcoma" to convey both the malignant behavior of these tumors and their close relationship with IMT.
See also
inflammatory myofibroblastic tumor
References
Epithelioid Inflammatory Myofibroblastic Sarcoma: An Aggressive Intra-abdominal Variant of Inflammatory Myofibroblastic Tumor With Nuclear Membrane or Perinuclear ALK. Mariño-Enríquez A, Wang WL, Roy A, Lopez-Terrada D, Lazar AJ, Fletcher CD, Coffin CM, Hornick JL. Am J Surg Pathol. 2011 Jan;35(1):135-44. PMID: #21164297#