Paraneoplastic myelitis associated with Waldenström macroglobulinemia responsive to treatment with ibrutinib – venetoclax: A case report

Abstract

Waldenström macroglobulinemia (WM) is a B-cell lymphoproliferative malignancy characterized by IgM paraproteinemia and presence of lymphoplasmacytic cells in the bone marrow. Isolated longitudinally extensive transverse myelitis (LETM) is a rare manifestation of WM. We report a rare case of paraneoplastic LETM in a 68-year-old male with treatment-naïve WM (MYD88 L265P mutation in bone marrow aspirate), who responded to ibrutinib and venetoclax therapy. Our patient presented with a two-month history of unsteadiness, tingling, and numbness in both hands and feet, that progressed to bilateral leg and arm weakness. Based on radiographic findings, a diagnosis of paraneoplastic LETM was made and he was treated acutely with IV methylprednisolone followed by a quick oral prednisone taper. However, he subsequently relapsed and symptomatically worsened while on rituximab therapy. Accounting for worsening anemia, our patient was enrolled in a Phase II trial evaluating the effects of ibrutinib-venetoclax therapy in treatment naïve WM. After three months of study therapy, he had a complete response of myelopathy symptoms and MRI lesions. Our observation of sustained disease response in this patient may support a role for concurrent BTK and BCL2 inhibition in paraneoplastic myelitis associated with B-cell lymphoproliferative disorders. However, this observation needs to be validated in larger cohort studies and potentially in clinical trials if further data are supportive.