DOI: https://doi.org/10.36347/sjmcr.2026.v14i08.030

Pages: 1889-1891

Extramedullary manifestations of multiple myeloma are rare, and involvement of the laryngeal cartilage remains exceptional. These lesions are important to recognize, as they can mimic a primary laryngeal tumor or a cartilaginous tumor, while reflecting aggressive tumor biology in the context of a plasma cell dyscrasia. We report the case of a 51-year-old man with no reported medical history or toxic habits, diagnosed in 2025 with kappa-monotypic plasmablastic multiple myeloma complicated by cardiac decompensation and treated with bortezomib, cyclophosphamide, and dexamethasone. During the evaluation of the lesions, imaging revealed diffuse active osteolytic lesions of the axial and peripheral skeleton, as well as a destructive left laryngeal lesion centered on the lateral lamina of the thyroid cartilage and infiltrating the ipsilateral cricoid cartilage. A cervical CT scan confirmed a destructive lesion centered on the laryngeal cartilages with heterogeneous enhancement after contrast injection. Laryngoscopy with biopsy of the lesion revealed a kappa-monoclonal plasma cell proliferation expressing CD138 and CD56, confirming laryngeal involvement by multiple myeloma. This observation highlights the rarity of involvement of the thyroid and cricoid cartilages, the need to include myeloma in the differential diagnosis of destructive lesions of the laryngeal cartilage, and the central role of histological confirmation prior to any therapeutic decision.