Neuroblastoma-like schwannoma of the skull base: an enigmatic peripheral nerve sheath tumor variant.

Neuroblastoma-like schwannoma is an extremely rare histological variant of schwannoma, which histologically mimics a malignant small round cell tumor. Only 19 cases have been reported in the literature to date. We report a case of this tumor located at the skull base in a 44-year-old woman who presented with symptoms of right-sided earache and hearing loss. MRI revealed a large, lobulated, extra-axial mass measuring 8.8 cm × 3.6 cm × 4.2 cm in the floor of the middle and posterior cranial fossa. Microscopic examination revealed a perplexing histopathology with peculiar collagenous rosettes. Differential diagnoses included a broad range of benign and malignant tumors. Typical schwannoma seldom poses a difficulty in diagnosis; however, this unusual variant is a diagnostic challenge which requires an extensive clinico-radiological correlation and immunohistochemical work-up. Hence, knowledge of this entity is a must to avoid erroneous diagnosis and inappropriate treatment. [ABSTRACT FROM AUTHOR]