Cutaneous extraskeletal Ewing sarcoma is a rare malignancy that usually presents as a small round cell tumour. We present a case of a young patient with a slow-growing skin nodule on the arm that was excised by their GP. The nodule’s morphological and immunohistochemical profile was unusual, characterising a vascular spindled small blue cell tumour with differentials including extraskeletal Ewing sarcoma, haemangioendothelioma, and angiomatoid fibrous histiocytoma. Through intradepartmental discussion, extradepartmental consultation and finally RNA-based molecular analysis, a diagnosis of cutaneous extraskeletal Ewing sarcoma was confirmed. We discuss the diagnostic approach used in this case and review the current literature on the utility of molecular analysis in this process.
Bazlee et al. (Sun,) studied this question.