Commentary.

Intracranial (IC) involvement in multiple myeloma (MM) is extremely rare, most frequently resulting from osseous lesions in the cranial vault and skull base or dural involvement (OD).[1] Central nervous system (CNS) MM consists in intraparenchymal localizations, cerebral plasma cytomas, or CNS myelomatosis, with the detection of malignant plasma cells in the cerebrospinal fluid (CSF). Moreover, the blood–brain barrier (BBB) constitutes a natural protection from commonly used drugs, with the effect of unsatisfactory responses. Patients described in the literature are few and treatments are variegate: debulking surgery, systemic chemotherapy, CHT, intrathecal therapy (IT), radiotherapy (RT) with median survivals of 1 month or less for CNS MM and 1 year or less for OD MM.[234567] RT has been so far the best-reported therapy for both these peculiar types of MM. With the advent of novel drugs such as bortezomib, thalidomide, and lenalidomide together with radiotherapy and autologous bone-marrow transplantation, we showed, in a retrospective trial,[5] that CNS myeloma can respond sometimes and survivals can be ameliorated. Moreover, OD myeloma can respond very well and patients can have similar survivals to the usual myeloma population.

In their interesting and peculiar case, Senapati et al,[8] reported about a 35-year-old female who presented with a huge extramedullary scalp and IC localization of MM at diagnosis. Extramedullary IC localization of MM is even rarer at diagnosis: in fact usually less than 10% of all IC MM involvements are present at diagnosis.[5]

When facing a patient with a cranial mass (or a spinal cord compression), MM should be ruled out in the differential diagnosis. It is really important to assess serum and urine total protein and electrophoresis, serum and urine immunofixation looking for a monoclonal component. I often, as hematologist, see the patient after a surgery debulking has been done, when I would prefer to be called earlier. Even though I believe that disease debulking is usually necessary as a diagnostic and therapeutic measure, it could be sometimes dangerous for the patient as in the present case. Some of the new drugs can be very efficacious in reducing the bulk of disease and nonetheless surgery risks.[5] In conclusion, we need to describe more and more cases with IC myeloma to try to know more about the clinical and biological point of view and, as shown by Senapati and colleagues, team work (neurosurgeon, hematologist, and radiotherapist) is fundamental in treating these patients.