Lesions occupying the anterior cranial fossa may arise de novo or are extensions from the sino-nasal areas with a handful of differentials in either group. The imaging findings, though to a large extent standardized are not full proof. Primary central nervous system lymphoma and sino-nasal lymphoma are uncommon variants of extranodal non-Hodgkin's lymphoma (NHL). We encountered a 35-year-old lady presenting with headache and seizures with a mass lesion involving the ethmoids with invasion into the anterior cranial fossa diagnosed as T-cell extranodal NHL. Gross total resection and reconstruction of the skull base were done. She was treated with chemotherapy and radiotherapy and is doing well at 6 months follow-up. This is the first report of a sino-nasal T-cell lymphoma invading the brain-parenchyma in an immuno-competent person. Sino-nasal primary T-cell lymphoma presenting as skull base pathology should form an essential differential diagnosis along with other routine lesions of anterior cranial fossa. Since these lesions have a good response to chemo and radiotherapy, a trans-nasal biopsy may obviate the need of a craniotomy if neurosurgeons are aware of this rare entity.
Keywords: Immunohistochemistry; T-cell; lymphoma; sino-nasal.