Leukemic Infiltration of Peripheral Nerve: Case Series and Review of the Literature (P06.133)

Abstract

Objective: To review the clinical, laboratory, electrophysiologic, radiologic and pathologic characteristics of leukemic infiltration of peripheral nerve. Background Leukemic infiltration of peripheral nerve is rare. Reported cases have occurred solely in patients with known systemic disease. Design/Methods: Mayo Clinic cases of leukemic infiltration of peripheral nerve identified between January, 2004 and October, 2011 were reviewed. Results: Five patients were identified. All were men with median age of 68 yrs (range 46-72) at time of symptom onset. Three patients had acute myeloid leukemia (AML) and 2 had chronic lymphocytic leukemia (CLL). In 3 patients the diagnosis of leukemia preceded neurological symptoms by 3-25 months. Two patients presented with peripheral nerve involvement and were found to have positive CSF cytology confirming the diagnosis of AML. All patients had painful, progressive motor and sensory deficits. Clinical patterns were mononeuropathy (1), multiple mononeuropathies (1), and plexopathy (3). Electrophysiological examination in 3/4 patients demonstrated a chronic axonal process and 1/4 demonstrated both axonal and demyelinating features. MRI detected mass lesions in 4/5 cases with PET imaging demonstrating avid FDG uptake. Three patients underwent peripheral nerve biopsy, 2 of which were diagnostic of leukemic infiltration. All patients received systemic chemotherapy (three with additional intrathecal chemotherapy) and 3 received radiation therapy. Patients experienced improvement in pain and partial improvement of neurological deficits. Four patients had disease relapse, 4 systemic and 1 also in peripheral nerve. Conclusions: Leukemic infiltration of peripheral nerve is rare. Patients may present with a progressive, painful mononeuropathy or plexopathy. CSF cytology can be diagnostic of leukemia in the absence of systemic involvement. MRI and PET imaging are useful in suggesting a hypermetabolic mass, raising suspicion of neoplasm. Nerve biopsy aids in confirming leukemic infiltration. Treatment with chemotherapy and/or radiation is recommended, but most patients ultimately experience disease relapse. Disclosure: Dr. Reddy has nothing to disclose. Dr. Mauermann has nothing to disclose. Dr. Begna has nothing to disclose. Dr. Ringler has nothing to disclose. Dr. Jerath has nothing to disclose. Dr. Amrami has nothing to disclose. Dr. Spinner has nothing to disclose.