Subglottic extramedullary plasmacytoma with light chain multiple myeloma masquerading as adult-onset asthma

Solitary Extramedullary Plasmacytoma of the Larynx and Secondary Laryngeal Involvement in Plasma Cell Myeloma: Single-Centre Retrospective Analysis and Systematic Literature Review

The involvement of the larynx in plasma cell myeloma (PCM) may manifest as solitary extramedullary plasmacytoma of the larynx (sEMP-L) or as infiltration of the larynx during newly diagnosed or relapsed systemic disease with bone marrow involvement (plasma cell myeloma with laryngeal involvement, PCM-L). To increase knowledge about these rare conditions, we performed a retrospective analysis along with a comprehensive literature review of cases of sEMP-L or PCM-L. Six patients (two sEMP-L and four PCM-L) were identified in our tertiary laryngological centre from 2009 to 2021, constituting 0.88% of all malignant laryngeal tumours. The literature search yielded 187 cases, including 152 sEMP-L and 35 sPCM-L. A comparison of baseline characteristics between sEMP-L and PCM-L performed in the combined cohort of cases from literature review and retrospective analysis revealed that patients with sEMP-L were younger (56 vs. 64 years, p ≤ 0.001) and presented less commonly with thyroid or cricoid cartilage involvement (2.2% vs. 30.8%, p ≤ 0.001). The prognosis of sEMP-L was better than PCM-L (overall survival 86% vs. 55% at 5 years, p = 0.002). Analysis of potential factors that could influence progression-free survival (PFS) in the group of sEMP-L revealed that male sex and cartilage involvement negatively affected PFS in univariate analyses, while only cartilage involvement retained statistical significance in multivariate analysis (HR = 19.94, p = 0.024). In conclusion, PCM with laryngeal involvement is sporadic. Secondary involvement of the larynx during PCM might be more common than sEMP-L and is associated with worse survival. The involvement of cartilage adversely influences the outcome of sEMP-L.

An Unusual Case of Multiple Myeloma with Light-Chain Cast Nephropathy Secondary to a Very Large Plasmacytoma without Bone Marrow Involvement

Here, we report a case of a patient who presented to Strong Memorial Hospital with new-onset renal failure and anemia and was found to have multiple myeloma with lambda light-chain cast nephropathy secondary to a very large (14 cm × 14 cm × 12 cm) plasmacytoma without bone marrow involvement. This case is notable as solitary plasmacytomas are almost never seen with concomitant myeloma-defining CRAB criteria or significantly elevated serum free light-chain ratios. Although solitary plasmacytomas are typically definitively treated with radiation, this case highlights that systemic treatment may be helpful in certain clinical scenarios.

An Overview of Light Chain Multiple Myeloma: Clinical Characteristics and Rarities, Management Strategies, and Disease Monitoring

Light chain multiple myeloma (LCMM) constitutes approximately 15% of patients with multiple myeloma (MM). It has a poorer prognosis when compared to immunoglobulin (Ig) G or IgA variant. We performed a comprehensive literature search on LCMM and identified a total of 390 articles. After a detailed screening, six studies involving a total of 1054 LCMM patients were included. A literature review revealed bone pain and renal failure as the most common initial sign and symptoms while extramedullary disease (EMD) was acquired later during the progression of the disease. Bortezomib has shown superior efficacy in LCMM patients over nonbortezomib regimens as demonstrated by better overall response rate (95.5% vs. 60%), progression-free survival (PFS) (25% vs. 9% at two years), and overall survival (OS) (24% vs. 9% at five years). Moreover, better PFS was seen, when bortezomib was used in combination with bendamustine compared to dexamethasone (95% vs. 25% at two years). Similarly, better OS (90% at two years) was observed with bortezomib in combination with bendamustine. Monitoring of disease should include serum free light chain levels, as literature review revealed that serum assays were more sensitive in indicating the disease and predicting PFS and OS as compared to urine assays. We provide presentation patterns, clinical rarities, management strategies including their efficacy, and disease monitoring in patients with LCMM in our review paper.