Spindle Cell Neoplasm with EML4-ALK Gene Fusion Presenting as an Intra-Osseous Vertebral Mass.

In this article we describe a spindle cell neoplasm harboring an EML4-ALK gene rearrangement presenting as an intraosseous vertebral mass with extension into the adjacent soft tissue in a 65-year-old man. Histologically, the lesion was characterized by the presence of monotonous, cytologically bland spindle cells with loose myxoedematous stroma and interspersed areas of amianthoid-like collagen fiber deposition. Immunohistochemistry demonstrated strong diffuse staining for CD34 and S100 with absent immunoreactivity for SOX10. At one year of follow-up after resection there is no evidence of local recurrence or metastatic disease. This case adds to the clinical and pathologic spectrum of a recently described group of kinase fusion-positive spindle cell neoplasms. The presence of ALK rearrangement in this lesion represents a potential therapeutic target, if clinically indicated. This article is protected by copyright. All rights reserved.