Imaging findings of cutaneous angiosarcoma of the scalp: Comparison with cutaneous squamous cell carcinoma

Purpose: This study aimed to evaluate imaging findings of cutaneous angiosarcoma (cAS) of the scalp compared with those of cutaneous squamous cell carcinoma (cSCC). Methods: This study included 15 patients with primary cAS and 10 with primary cSCC of the scalp. Seven patients with cAS and eight with cSCC underwent magnetic resonance imaging, and 11 patients with cAS and eight with cSCC underwent F-18-fluorodeoxyglucose-positron emission tomography/computed tomography imaging. Imaging findings for both pathologies were retrospectively reviewed and compared. Results: All 15 cAS cases were elevated lesions with an obtuse angle, invading the subcutaneous fat tissue. Multiple lesions were observed in only five cAS cases (33%) and no cSCC cases. Maximum diameter-to-height ratio was significantly higher in cAS than in cSCC (3.3 +/- 1.0 versus 2.3 +/- 0.6; p < 0.01). On T2-weighted images, intratumoral hypointensity (86% versus 13%; p < 0.01) and mixed hyper- and hypointensity (71% versus 0%; p < 0.01) were observed more frequently in cAS than in cSCC. No significant differences were observed between cAS and cSCC regarding flow void (29% versus 25%; p = 0.656). Maximum standardized uptake values were marginally significantly lower in cAS than in cSCC (5.6 +/- 3.1 versus 10.5 +/- 6.6; p = 0.078). Conclusions: Cases of cAS of the scalp always exhibited flat elevated lesions with invasion of the subcutaneous fat tissue. Compared with cSCC, intratumoral hypointensity and mixed hyper- and hypointensity on T2-weighted images were more frequent in cAS. These findings will help with the differential diagnosis of cAS.