Introduction: In neurolymphomatosis (NL), the affected nerves are typically described to be enlarged and hyperintense on T2WI MR sequences and to avidly enhance on gadolinium enhanced T1WI. This pattern is highly non-specific. We recently became aware of a “tumefactive pattern” of NL, neuroleukemiosis (NLK) and neuroplasmacytoma (NPLC), which we believe is exclusive to hematologic diseases affecting peripheral nerves.
Methods: We defined a “tumefactive” appearance as complex, fusiform, hyperintense on T2WI, circumferential tumor masses encasing the involved peripheral nerves (Fig. 1). Both structures show varying level of homogenous enhancement. The nerves appear to be infiltrated by the tumor. We reviewed our series of 52 cases of NL in search for this pattern; 2 extra outside cases of NL, 3 cases of NLK and 1 case of NPLC were added to the series.
Results: We identified 20 tumefactive lesions in 18 patients (14 NL, 3, NLK, 1 NPLC). The brachial plexus (n = 7) was most commonly affected, followed by the sciatic nerve (n=6) and lumbosacral plexus (n=3). Four patients had involvement of other nerves. All were proven by biopsy: the diagnosis was high-grade lymphoma (n=12), low-grade lymphoma (n=3), acute leukemia (n=2), and plasmacytoma (n=1).
Conclusions: We present an imaging pattern of “tumefactive” NL, NLK, or NPLC seen in 18 patients. We believe this pattern is associated with hematologic diseases directly involving peripheral nerves.
Patient Care: Newly identified imaging association of hematologic malignancies involving peripheral nerves provides a clue to clinicians in establishing the correct diagnosis.
Learning Objectives: By the conclusion of this session, participants should be able to identify selected cases of peripheral nerve involvement by a hematologic malignancy based on their MR and ultrasound appearance.