Primary disease sites and patterns of spread in cases of neurolymphomatosis in the orbit associated with lymphoma

BACKGROUND: Neurolymphomatosis involving the cranial nerves (CNs) is rare. We sought a better understanding of the primary disease sites and patterns of spread in neurolymphomatosis of the orbit and retro-orbital cranial nerves. METHODS: Patients with lymphoma and MRI evidence of neurolymphomatosis of CN II, III, IV, V(1), or V(2) were retrospectively reviewed. Demographics and primary disease site and sites of neurolymphomatosis on MRI were recorded. Wilcoxon rank sum test was used to compare number of sites of neurolymphomatosis with lymphoma type and survival. RESULTS: The study included 18 patients. The most frequent types of lymphoma were diffuse large B-cell (DLBCL) (n = 9) and marginal zone (n = 3). In 9 patients, lymphoma presented as a mass (n = 7) or infiltrative disease (n = 2) directly involving the orbit; in 6, a maxillofacial mass spread directly to CNs; and in 3, lymphoma at remote sites spread to orbital CNs. Overall, 81 sites of neurolymphomatosis were noted. The most common sites were the maxillary nerve (V(2)) including at the infraorbital fissure or foramen rotundum (17 patients; 19 nerves), pterygopalatine fossa (16 patients; 19 nerves), and cavernous sinus (9 patients; 12 nerves). Number of sites of neurolymphomatosis was significantly lower for DLBCL than for other lymphoma types (p = 0.007). Number of sites of neurolymphomatosis did not affect survival (p = 0.26). The mean interval between the pathologic diagnosis and MRI documentation of the full extent of neurolymphomatosis was 39 days after pathologic diagnosis. CONCLUSIONS: Based on our study results, neurolymphomatosis in the orbit appears to be frequently associated with an orbital and/or maxillofacial mass and commonly involves CN V(2), the pterygopalatine fossa, and the cavernous sinus. DLBCL may be associated with fewer sites of neurolymphomatosis than other lymphomas. In patients with lymphoma, a systematic search for neurolymphomatosis is imperative for early detection.