Unique occurrence of mucosa-associated lymphoid tissue lymphoma disseminated to peripheral nerves.

Lymphomatous spread to peripheral nerves is a rare but long recognized complication, most commonly involving aggressive B-cell lymphomas. A 67-year-old woman with a history of a low-grade, gastric mucosa-associated lymphoid tissue (MALT) lymphoma, which was in remission, presented with a left-sided forearm mass and numbness over the dorsolateral aspect of the thumb. Magnetic resonance imaging revealed a mass associated with the superficial radial sensory nerve in the distal forearm, which demonstrated fluorodeoxyglucose avidity on positron emission tomography. An ultrasound-guided needle biopsy was performed yielding a diagnosis of low-grade lymphoma, consistent with extranodal marginal zone lymphoma. Subsequently, she was found to have bilateral sciatic nerve involvement. This case describes the first known reported spread of MALT lymphoma to peripheral nerves in the limbs.