Paraspinal mesenchymal tumors: the overlap between neuropathology and soft tissue pathology

Mesenchymal/soft tissue tumours represent a broad spectrum of lesions, ranging from benign processes to malignant sarcomas. Presenting at virtually any anatomic site, they are encountered in the surgical pathology workload of all histopathologists. The diagnosis can be substantially challenging, especially in small biopsy specimen, and require integration of morphology, clinical data, and ancillary studies. Herein, we review the most common mesenchymal/soft tissue tumours encountered in the central nervous system with particular focus on the paraspinal region, highlighting key points to help the general pathologists approaching such cases, and describing how to distinguish these lesions from potential mimics. In this article we broadly divide the discussed entities into four major categories, primarily based on their morphologic patterns: small round blue cell tumours, non-neural spindle cell tumours, vascular lesions and other (to include chordomas and chondrosarcoma).