Widely Infiltrating Epithelioid Malignant Peripheral Nerve Sheath Tumour of Skull Base

The epithelioid variant of malignant peripheral nerve sheath tumours is a rare histological entity, and the occurrence of a malignant peripheral nerve sheath tumour in the skull base is even more unusual. We report a case of a 52-year-old man who presented with reduced hearing in the left ear, giddiness and left-sided facial weakness of short duration. He was a known hypertensive. On examination, left-sided 7th to 12th cranial nerve palsies were noted. Computed tomography (CT) and brain magnetic resonance imaging (MRI) were reported as an ill-defined heterogeneously enhancing mass left skull base suggestive of chondrosarcoma. Left tympanotomy and biopsy of the lesion were carried out. On light microscopy and immunohistochemical examination of the biopsy, a diagnosis of epithelioid malignant peripheral nerve sheath tumour was established. The patient underwent left extended modified radical mastoidectomy and selective neck dissection. Histopathological study of the resected surgical specimen confirmed left-sided extensive tumour involvement of skull base structures, as well as neck nodal metastases.