Intravascular fasciitis leading to an aortic dissection. A case report.

Here we report on the case of a 61-year-old female with an accidental finding of intravascular fasciitis (IVF) affecting the ascending aorta in a specimen resected due to an acute aortic dissection. No infiltrative process of the aorta or surrounding soft tissues was grossly apparent. Microscopically, the lesion had poorly defined margins and was composed of plump spindle- and oval-shaped cells set in an abundant myxoid stroma. Immunohistochemically, cytoplasmic positivity for β-catenin was observed and about 25% of cells were positive for calponin. The Ki-67 index was approximately 25% (increasing to about 50% in hot spot areas). Occasional isolated cells also showed positivity for alpha actin. Other markers were all negative in the tumor cells including; smooth muscle actin, desmin, h-caldesmon, D2-40, DOG1, S100 protein, CD34, CD31, ERG, melan A, HMB45, IgG, IgG4, ALK, cytokeratin AE1/AE3, and LCA. Intravascular fasciitis is a benign myofibroblastic proliferation which most commonly occurs in subcutaneous tissues and may mimic malignancy. To the best of our knowledge this is only the 2nd ever reported case of IVF affecting the aorta. Keywords: intravascular fasciitis - nodular fasciitis - soft tissue lesions - myofibroblasts - aorta.