Clinical Spectrum and Early Outcomes of IgD Multiple Myeloma: A Three-Patient Case Series from a Mexican Tertiary Referral Center
1. Introduction:
Immunoglobulin D (IgD) multiple myeloma is a rare plasma cell disorder, accounting for approximately 1-2% of multiple myeloma cases. It is often associated with younger age, renal impairment, low or absent measurable serum monoclonal protein, elevated lactate dehydrogenase (LDH), extramedullary disease, and aggressive clinical behavior. Contemporary real-world information from Latin America remains limited. We describe the clinical presentation, treatment, and early outcomes of three patients with IgD multiple myeloma diagnosed at a tertiary referral center in Mexico.
Materials and Methods/Case Presentation/Objective:
2. Materials and Methods:
We performed a retrospective descriptive review of all patients diagnosed with IgD multiple myeloma at our institution between October 2024 and July 2026. Demographic characteristics, immunoglobulin and light-chain subtype, clinical and imaging findings, organ involvement, baseline LDH, treatment, response, progression, and survival were collected from medical records retrospectively. The objective was to characterize the clinical heterogeneity, high-risk manifestations, and early outcomes of IgD multiple myeloma in routine practice.
Results/Description/Main Outcome Measure(s):
3. Results:
Among 89 patients with newly diagnosed multiple myeloma, three had IgD multiple myeloma, representing 3.37% of the cohort; median age was 43 years, two were men, and two had lambda light-chain disease. Patient 1 was a 38-year-old man with oligosecretory IgD kappa multiple myeloma and LDH of 157 U/L. Imaging demonstrated extensive osseous disease involving the posterior right ninth and twelfth ribs, a 63 × 55 × 57 mm right first metacarpal lesion with soft-tissue extension, a 46 × 25 mm left hemisacral lesion with neuroforaminal involvement, the left iliac bone, and multiple punched-out skull lesions. Treatment was initiated with daratumumab, bortezomib, lenalidomide, and dexamethasone using a PERSEUS-based approach.
Patient 2 was a 43-year-old man with IgD lambda multiple myeloma and LDH of 581 U/L. He presented with severe renal failure requiring hemodialysis and extramedullary testicular involvement. He received bortezomib, lenalidomide, and dexamethasone, achieved a very good partial response, but developed disease progression after three months of therapy before autologous stem cell transplantation could be performed.
Patient 3 was a 54-year-old woman with IgD lambda multiple myeloma, renal failure, anemia, and LDH of 2,294 U/L. She had extensive extramedullary disease involving the breast, lungs, lymph nodes, diaphragm, liver, spleen, skeletal muscle, and pancreas. Endoscopic ultrasound-guided fine-needle aspiration of a pancreatic body and tail mass confirmed a malignant plasma cell neoplasm. She died from multiorgan failure nine days after diagnosis.
Conclusion(s).:
4. Conclusion(s)
Only three IgD cases were identified during the 22-month study period, emphasizing the rarity of this subtype. Nevertheless, all showed clinically aggressive or high-risk manifestations, including oligosecretory disease, extensive bone involvement, renal failure, extramedullary dissemination, or markedly elevated LDH. Two patients had rapid progression or early death despite treatment or before effective therapy could be established. These results support early diagnostic recognition, systematic assessment for renal and extramedullary involvement,
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