Multiple myeloma

By Marcello Cherchi, MD PhD

For clinicians

Overview

Multiple myeloma (MM) the second most common hematologic malignancy, and consists of pathological proliferation of monoclonal plasma cells in bone marrow.  These plasma cells overproduce immunoglobulins which accumulate in, and interact with, other cells, leading to a variety of problems in multiple organ systems (bone lesions, hypercalcemia, renal failure, anemia, infection) (Brigle and Rogers 2017).

Introduction

Multiple myeloma (MM) is the second most common hematologic malignancy, and consists of pathological proliferation of monoclonal plasma cells in bone marrow. These plasma cells overproduce immunoglobulins which accumulate in, and interact with, other cells, leading to a variety of problems in multiple organ systems (bone lesions, hypercalcemia, renal failure, anemia, infection) (Brigle and Rogers 2017).

Vestibulocochlear manifestations of multiple myeloma

It is very unusual for multiple myeloma to cause auditory or vestibular symptoms, and as of this writing, the literature on this topic consists of only case reports. Most such cases occur when a plasmacytoma involves the skull base and either impinges on the vestibulocochlear nerve (Joshi, Jiang et al. 2011, Rakul Nambiar, Nair et al. 2017), or on the cerebellum (Pika, Bacovsky et al. 2009, Tathineni, Cancarevic et al. 2020).

We have seen many patients who carry a diagnosis of multiple myeloma, but none in whom that disease has been proven as the cause of audiologic or vestibular symptoms.

If the mechanism is compression of the vestibulocochlear nerve by a lytic or space-occupying plasmacytoma in the skull base, then we would anticipate that the auditory symptoms would correspond to sensorineural hearing loss on audiometry, and the disequilibrium would correspond to vestibular weakness. Oddly, one case report (Joshi, Jiang et al. 2011) instead describes a mixed hearing loss, suggesting possible middle ear involvement. None of the literature reports results of any vestibular testing.

If the mechanism of disequilibrium is due to cerebellar compression by a space-occupying plasmacytoma, then (depending on the location of the lesion) we would anticipate either appendicular or midline cerebellar findings on physical examination. We would also anticipate cerebellar ocular motor findings on oculography, but no ocular motor data were presented in any of the published studies.

References