Evaluation of PRAME immunohistochemistry in cutaneous vascular neoplasms reveals frequent expression in primary and post-irradiation cutaneous angiosarcomas

Background

Preferentially expressed antigen in melanoma (PRAME) has been extensively studied in cutaneous melanocytic tumors and has proven valuable as a diagnostic adjunct in routine dermatopathology practice. However, its expression in cutaneous vascular neoplasms, particularly angiosarcomas (AS), remains largely unexplored.

Methods

To further explore PRAME expression in cutaneous AS, 18 cases of post-irradiation and 13 cases of primary cutaneous AS were evaluated for PRAME. For comparison, sections from 11 deep soft tissue/visceral AS, 10 Kaposi sarcomas, 8 microvenular hemangiomas, 7 infantile hemangiomas, 8 atypical vascular lesions, 6 epithelioid hemangioendotheliomas, 6 pyogenic granulomas, 6 papillary endothelial hyperplasias, 6 epithelioid hemangiomas, 3 capillovenous malformations, 3 hobnail hemangiomas, 2 spindle cell hemangiomas, 2 pseudomyogenic hemangioendotheliomas, and 2 composite hemangioendotheliomas were also retrieved.

Results

Overall, 22 of 31 (70.9%; 12 post-irradiation and 10 primary) cutaneous AS were positive for PRAME. In contrast, only 1 of 11 (9.1%) deep soft tissue/visceral AS showed diffuse and strong PRAME nuclear staining. All other tumor types were negative for PRAME, except for 5 of 7 (71.4%) infantile hemangiomas, which demonstrated rare (<5%; four cases) and 1+ (5–25%; one case) nuclear staining.

Conclusions

In this study, we have demonstrated frequent nuclear PRAME expression in cutaneous AS. PRAME immunohistochemistry may serve as a valuable additional marker in selected clinical settings.