A Rare Presentation of Sphenoid Sinus Lymphoma in an 18-Year-Old Female.

Sphenoid sinus lymphomas are extremely rare, constituting a small fraction of both sphenoid sinus malignancies and extranodal non-Hodgkin lymphomas. Their clinical presentation can vary widely, ranging from symptoms resembling chronic sinusitis to more severe manifestations such as nerve palsies and visual disturbances. An 18-year-old female with no significant medical history presented with blurred vision, diplopia, and a left-sided headache lasting one week. Neurological examination revealed mild limitation of lateral rectus movement in the left eye. Imaging studies, including non-contrast CT and MRI, identified a hyperdense mass arising from the left sphenoid sinus. A biopsy obtained via a transnasal sphenoidal approach confirmed a diagnosis of pre-B cell lymphoblastic lymphoma. Following the biopsy, the patient was treated with IV dexamethasone, leading to complete resolution of her symptoms and regression of the mass on follow-up imaging. Staging confirmed the diagnosis of stage 1A B-cell lymphoblastic lymphoma. The patient underwent chemotherapy and radiotherapy and remains in remission five years later. However, she developed bilateral hip avascular necrosis as a side effect, requiring hip replacement surgery. Diagnosing sphenoid sinus lymphoma can be challenging due to its nonspecific symptoms and the complex anatomy of the sphenoid sinus, often leading to misdiagnosis as more common conditions such as sinusitis or cranial nerve palsies. Imaging, particularly MRI and CT, plays a critical role in assessing the disease's extent and evaluating potential cranial nerve involvement. A biopsy is essential for obtaining a definitive histological diagnosis to guide appropriate treatment plans. While steroids can offer rapid symptom relief, the primary treatment for sphenoid sinus lymphoma involves chemotherapy, often in combination with radiotherapy. Surgery is typically not recommended due to the tumor's location and potential risks to surrounding structures. The case highlights the importance of considering neoplastic lesions in patients presenting with unexplained headaches and ocular findings to support timely diagnosis.