[Infiltrative peripheral neuropathy of acute monoblastic leukemia during hematologic remission]

A 38-year-old woman with acute monoblastic leukemia developed severe continuous pain in the left arm while she was in hematologic remission following both systemic and intrathecal chemotherapy. A nerve conduction study (NCS) showed marked decrease of amplitude in the left ulnar nerve, consistent with infiltration of leukemic cells. The pain in the arm was reduced by irradiation to the left brachial plexus, but right facial nerve palsy occurred. No improvement was achieved by systemic and intrathecal chemotherapy plus irradiation to the whole brain and right parotid. After sometime, she complained of pains in the legs and right foot drop. NCS showed amplitude decrease in bilateral peroneal nerve. Throughout the course, bone marrow remained in complete remission, and no signs of meningeal leukemia were obtained. A treatment with high dose Ara-C appeared to be effective for the pain in the legs. The foot drop, however, persisted and peripheral neuropathy progressed even after high dose Ara-C therapy. Peripheral nerve involvement in acute leukemia appears to be rare, and even more so in case of hematologic remission. The blood-nerve barrier may allow some malignant cells to escape from cytotoxic agents. Therefore, irradiation or high dose Ara-C therapy would seem to be rational approaches to the problem.