Perivascular mantle cell lymphoma affecting a temporal artery--a highly unusual cause of temporal headache.

Introduction: Temporal artery biopsy is a widely performed procedure for clinically suspected temporal arteritis. We the report the case of a 79-year-old male with mantle cell non-Hodgkin's lymphoma previously treated with chemotherapy under follow-up with right-sided orbital recurrence, who developed right temporal headache, tenderness, and visual symptoms in the right eye. His symptoms were unresponsive to steroid treatment and he underwent a temporal artery biopsy.

Methods: The temporal artery was fixed in standard 10% buffered formalin, processed to paraffin wax, 4 micron sections cut through the entire artery and stained with standard haematoxylin and eosin. Some sections were exposed to CD20, CD5, and cyclin D1 immunohistochemistry.

Results: Histology showed a perivascular, nodular lymphoid infiltrate composed of small centrocyte-type lymphocytes around the main artery and identical lymphocytes within the wall of a main artery branch. Additionally, the lymphocytes were located around a peripheral nerve in the peri-artery connective soft tissues. These lymphocytes were positive for CD5, CD20, and cyclin D1 indicating a diagnosis of peri-neural, peri-vascular mantle cell non-Hodgkin's lymphoma of identical appearance to that in the index biopsy.

Conclusions: This report describes a highly unusual histological and clinical scenario of peri-temporal artery Mantle cell lymphoma causing temporal headache from peripheral nerve and artery side branch involvement by the lymphoma immediately adjacent to the temporal artery. We propose that involvement of a temporal artery by lymphoma be considered in the differential diagnosis, in patients with an established diagnosis of lymphoma, if presenting with "temporal arteritis" type headache symptoms.