Plasmamyelose

Plasmamyelose is a term that has appeared in a small number of case reports and speculative discussions to describe a demyelinating disorder associated with abnormal plasma cell activity within the central nervous system, particularly the spinal cord. It is not widely recognized in standard medical classifications or guidelines, and its exact definition varies between sources.

The name derives from plasma (plasma cells) and myel- (relating to the spinal cord or myelin). It is distinct from plasmacytoma (a plasma cell tumor) and from plasmacytosis (increased plasma cells in blood or marrow). Some authors consider plasmamyelose a syndrome rather than a single, well-defined disease, and it is sometimes discussed in the context of plasma cell–driven inflammatory or demyelinating processes.

Clinical features are variable and often subacute to chronic. Common signs include progressive motor weakness, spasticity, sensory loss below the affected spinal levels, gait disturbance, and sometimes bladder or bowel dysfunction. Symptoms may correlate with focal spinal cord involvement, and systemic signs are typically absent or mild.

Pathophysiology is not well established. Proposed mechanisms include perivascular infiltration of plasma cells within the CNS, local production of immunoglobulins, and secondary demyelination. Associations with monoclonal gammopathy or autoimmune autoantibodies have been reported in some cases, but causal relationships remain unproven.

Diagnosis relies on imaging and laboratory workup. MRI may reveal demyelinating lesions in the spinal cord or CNS. CSF analysis can show inflammatory changes and occasionally oligoclonal bands; biopsy or CSF testing for clonal plasma cells or plasma cell–specific markers (eg, CD138) can support a plasmacytic component. Other demyelinating or infectious diseases are excluded.

Treatment is not standardized due to rarity. Reported approaches include high-dose corticosteroids, plasma exchange, intravenous immunoglobulin, and plasma cell–targeted therapies such as rituximab in selected cases. Management of any underlying plasma cell dyscrasia is considered when present. Prognosis is highly uncertain, reflecting limited data and considerable heterogeneity. Further research and standardized criteria are needed to define plasmamyelose and guide care.