The patient is an 18-year-old boy not known to have any medical illness previously, who was referred to the outpatient department from another hospital after 3 months history of seizures. Seizures started with blurring of vision and proceed to right sided head deviation and tonic posturing of the right upper limp which progress to generalized tonic-clonic seizures. The episodes are followed by loss of consciousness and postictal suboccipital and frontal tension headache. There was no history of fever, loss of weight, trauma, or any sensory/motor neurodificit. Family history was unremarkable, with negative past surgical history. All general and local physical examinations were done and all were within normal range. There were no physical findings or family history in favour of neurofibromatosis. Brain MRI with contrast was done and showed right parieto-occipital cortical and subcortical mass lesion measuring about 1.5 x 1.5 cm that has a low signal intensity on T1 and intermediate signal intensity on T2 and FLAIR with intense enhancement postgadolinium administration mainly peripherally with few small susceptibility artefact on T2 associated with significant vasogenic oedema and mass effect on the adjacent sulci (Figure 1).
The radiological impression with the above description was most likely representing granulomatous infection (TB) or metastasis. Although a preoperative diagnosis could not be clearly established, the tumor was surgically removed through a right occipital craniotomy. The dura was incised and small area of discoloration was noted. Cortical dissection was done, with multiple pieces for frozen section, which was diagnosed later as suggestive of schwannoma, differential diagnosis meningioma. The tumor was encountered 2mm in subcortical area, which was firm, fibrous in content, yellowish in colour, and resembling meningioma. Postoperatively, the patient did not have any new neurological deficit, and he was discharged 1 day postoperatively in stable condition to be seen and followed up in the clinic after 2 months. He was kept on phenytoin 100 mg orally three times a day and Paracetamol 650 mg tablets 4 hourly PRN. Microscopic examination of the tissue showed areas of nuclear palisading of bland looking spindle cells with dens cellular area alternating with loosely textured myxoid area, consistent with Antoni type A and Antoni Type B, respectively (Figure 2).
Immunohistochemical study was diffusely positive for S100 protein and negative for EMA, confirming the diagnosis of schwannoma (WHO grade1).