Peripheral CD19+ B cells are increased in children with active steroid-sensitive nephrotic syndrome

Though rare, direct invasion of CNS by the myeloma cells has been reported. Currently, 70 cases of leptomeningeal myelomatosis (LMM) and intraparenchymal plasmacytoma have been published [1,2]. Schluterman et.al. published a case series of 23 patients. They were diagnosed up to 29 months (median, 13 months) after the initial diagnosis of MM. The presenting symptom in 65% of the patients was AMS. The CSF analysis revealed pleocytosis and/or increased protein (generally >100 g/dl) similar to our case. CSF cytology showed myeloma cells; however, it was negative in 4 out of the 23 patients at initial presentation. Unlike our patient, cranial leptomeningeal contrast enhancement was seen on MRI in as many as 70% of the cases. Our patient did not fulfil all the diagnostic criteria of LMM but did have a dramatic recovery of his sensorium after the first cycle of dexamethasone therapy. His altered mental sensorium may represent a paraneoplastic manifestation of MM or alternatively, the patient falls into the spectrum of disease activity before fully evolved LMM. He was discharged from the hospital and was referred to an oncologist for further management of MM. In conclusion, altered mental status in a patient with multiple myeloma may be due to a paraneoplastic manifestation of MM or due to direct invasion of the CNS by myeloma cells. Intrathecal chemotherapy should be used for patients that meet the diagnostic criteria of LMM. However, even those who do not may still show a significant improvement in their neurologic status after treatment with intravenous dexamethasone.