Paediatric calcified intramedullary schwannoma at conus: A common tumor in a vicarious location

Abstract

Spinal schwannomas are commonly intradural extramedullary in location. As Schwann cells are not common in the central nervous system, intramedullary schwannomas are a rare entity. In adults, an estimated sixty cases have been reported in English literature. They are rarer in children (less than ten cases), and preoperative diagnosis becomes a prerogative in achieving total excision. Cervical cord is a common location and less commonly they occur in the conus. We report a rare case of calcified conus intramedullary schwannoma in a child without neurofibromatosis, who presented with conus-cauda syndrome of 1-year duration. Literature has been reviewed regarding its origin, pathophysiology, radiological features, and surgical management. This child underwent laminotomy and subtotal resection of the lesion. Histopathologically, tumor had typical features of schwannoma and was positive for S-100 immunoperoxidase. We believe that schwannoma needs to be considered in the preoperative differential diagnosis of a conus tumor in children as complete excision is possible in these benign tumors, thus affecting a cure.

Keywords: Calcification; conus lesion; differential diagnosis; foot drop; intramedullary schwannoma.

Figure 1

(a and b) T1-weighted sagittal and coronal contrast magnetic resonance imaging showing an intramedullary enhancing conus lesion with well-defined borders opposite D11–D12 vertebra. (c) T2-weighted coronal magnetic resonance imaging showing hypointense calcification superiorly. (d) T2-weighted sagittal magnetic resonance imaging showing calcification and a superiorly located small syrinx. (e and f) Axial magnetic resonance imaging showing the conus enlargement due to a contrast enhancing tumor with calcification

Figure 2

Large rounded circumscribed lesion walled in by thick collagenous band (a). Lesion has spindled cells with wavy nuclei (*b) that strongly expresses S-100 antigen confirming Schwannian origin (b, inset). Large zone of xanthomatous change present in the tumor (c, X) (a-c: H and E scale bar: 5 mm, 50 μm, 500 μm; b: inset: S-100 immunoperoxidase)