Epithelioid angiosarcoma of the calf: a case report of an atypical imaging appearance

Angiosarcoma is an uncommon cause of soft tissue malignancy, accounting for approximately 2% of all soft tissue sarcomas. Of these, epithelioid angiosarcoma represents a morphologic subtype, where the malignant endothelial cells demonstrate a predominantly or exclusively epithelioid appearance. Overall, epithelioid angiosarcoma shares similar imaging characteristics to conventional angiosarcoma including a T1 hypointense to isointense and T2 hyperintense mass, which demonstrates avid enhancement, serpentine feeding vessels, and overlying skin thickening on MRI. The case herein describes a case of epithelioid angiosarcoma in a 65-year-old female presenting with an enlarging calf mass and lower extremity pain. Initial imaging features, particularly on MRI, were highly unusual for angiosarcoma which was thus not strongly considered in the initial differential diagnosis. However, once diagnosis of epithelioid angiosarcoma was confirmed following resection, pathologic correlates were utilized to account for the unusual imaging findings retrospectively. The goal of this study is to not only describe an atypical presentation of an uncommon diagnosis but also attempt to rationalize the unexpected imaging findings with gross and microscopic correlates. Further, the utility of radiology-pathology correlation demonstrated in this case may be useful to others when evaluating similar lesions with unexpected MRI characteristics.