The Rarest Subtype of Plasma Cell Dyscrasia: IgE Multiple Myeloma

Abstract

IgE multiple myeloma is an exceptionally unique subtype of plasma cell dyscrasia, accounting for only a marginal percentage of all multiple myeloma cases. Combined with its lack of generalized accepted treatment approaches, its rarity makes diagnosis and clinical management extremely difficult. Here, we report the case of a 50-year-old woman with no prior medical history who presented with progressive bone pain over a one-year period. She underwent an exhaustive diagnostic workup, which included imaging, laboratory workup, histopathology, and cytogenetic analysis. The integrated diagnosis was IgE multiple myeloma associated with t(11;14) translocation. The patient had primary refractoriness to two lines of therapy incorporating immunomodulatory imide drugs and proteasome inhibitors (VRD and CTD regimens). After that, she was started on the DKD protocol consisting of daratumumab (Darzalex) and carfilzomib, with which she experienced a positive clinical and hematologic response. She is now in active surveillance and continues to respond well. Research on IgE multiple myeloma is sparse due to its rarity, but so is research around prognosis, ideal treatment options, and response to newer agents. There is little data because the literature is often based on case reports.

Keywords: ige multiple myeloma; immunoglobulin e; multiple myeloma; plasma cell dyscrasia; rare; t(11.14).

Figure 1. Detection of an IgE kappa paraprotein confirmed through serum protein electrophoresis and immunofixation.

(A, B) Serum immunofixation demonstrating the IgE-kappa MC (bands corresponding to the regions of anti-igE and anti-CLL kappa antisera).

Figure 2. Bone marrow showing a massive infiltration of 75% by dystrophic plasma cells.

Figure 3. FISH showing the IGH-CCND1 translocation, t(11;14)(q13;q32).

Fluorescence in situ hybridization (FISH) with dual fusion probes for immunoglobulin heavy chain (IGH) and cyclin D1 (CCND1) showing a fusion signal corresponding to t(11;14)/IGH-CCND1 fusion, and interphase FISH with a probe for cyclin-dependent kinases regulatory subunit 1 (CKS1B), a chromosome 1q marker, showing four copies of CKS1B.