MRI features of Stewart-Treves syndrome: a case series and systematic review

To comprehensively summarize the magnetic resonance imaging (MRI) features of angiosarcomas presenting as Stewart-Treves syndrome (STS) through a retrospective case series and systematic review of previous publications.

We identified five patients with STS from our institutional database and 25 patients with STS from 15 publications through a systemic review. We reviewed the MR features of 30 patients with STS, including five males and 25 females with a mean age of 59.5 years.

The tumors most commonly involved both the cutis and subcutis (17/25, 68.0%); the remaining tumors were limited to the cutis or subcutis. Multiple tumors were observed in more than half of the cases (16/27, 59.3%), and most of the tumors had poorly defined margins (26/28, 92.9%). The most common signal intensities of the tumors on T1-weighted images were intermediate (16/19, 84.2%), and the remainder were a mixture of intermediate and high, with a predominance of intermediate signal intensity. The signal intensities of the tumors on T2-weighted images were intermediate in seven cases (7/13, 53.8%), a mixture of intermediate and high in five cases (5/13, 38.5%), and a mixture of intermediate and low in one case (1/13, 7.7%). Available diffusion-weighted images from four institutional cases showed restricted diffusion of the tumors with mean apparent diffusion coefficient (ADC) values ranging from 0.77 × 10^-3 mm²/s to 0.96 × 10^-3 mm²/s.

Typical MRI features of angiosarcomas in STS were superficially located in multiple masses with ill-defined margins. Internal signal intensity was intermediate on T1-weighted images, and intermediate or a mixture of intermediate and high on T2-weighted images. ADC values obtained from the limited number of cases were low.