B-cell non-Hodgkin's lymphoma of the paranasal sinuses.

Primary nasal, paranasal, oral and pharyngeal (NPOP) lymphoma, thought to be a distinct entity among childhood lymphomas, may present with a wide variety of common ENT symptoms such as nasal obstruction, rhinorrhoea, epistaxis or sinusitis. The diagnosis may only be recognized when the disease results in symptoms such as visual loss, facial paraesthesia or lymphadenopathy, or systemic symptoms, such as fatigue, bone pain or abdominal pain. Full radiological assessment plays a vital part in making the diagnosis and planning treatment. Computerized tomography (CT) gives excellent bony detail but magnetic resonance imaging (MRI) using T2-weighted images, allows differentiation of mucosal thickening and retained sinus secretions from the tumour. Extension into the surrounding spaces and the cranial fossa is best assessed by coronal and sagittal T2 images. MRI is the best technique for follow-up because no radiation is involved and better soft tissue delineation improves the distinguishing of tumour from fibrosis.