Tehran University of Medical Sciences International Journal of Hematology-Oncology and Stem Cell Research 2008-2207 19 4 2025 10 16 429 433 Osias Vieira de Oliveira-Filho 1) Ceará Oncology and Hematology Center, Fortaleza, CE, Brazil 2)Department of Dentistry, Christus University Center, Fortaleza, CE, Brazil Yuri de Lima Medeiros Department of Stomatology, University of São Paulo, São Paulo, SP, Brazil Lorena Dos Santos Girão Department of Stomatology, University of São Paulo, São Paulo, SP, Brazil Igor Campos Guimarães Department of Public Health, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil Henrique Girão Martins Ceará Oncology and Hematology Center, Fortaleza, CE, Brazil André Costa Teixeira Medical School, Christus University Center, Fortaleza, CE, Brazil Saygo Tomo Department of Pathology, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil 2025 06 03 2025 09 15 Amyloidosis is characterized by extracellular deposition of amyloid material in various tissues and organs. Deposition of amyloid in the tongue is rare but often occurs in multiple myeloma. Here we present the case of a 44-year-old woman under treatment for multiple myeloma who complained of lateral tongue pain. Intraoral examination revealed an ill-defined, firm, whitish swelling with an ulcerated surface on the bilateral borders of the tongue. Histopathological analysis revealed a lympho-mononuclear infiltration in the lamina propria with the presence of acellular and amorphous material positive for Congo red staining. Further examination revealed amyloidosis in a cervical mass associated with neural compression. Thorough examination of the oral cavity in patients with multiple myeloma is critical for early detection of amyloidosis. A biopsy is mandatory to confirm the diagnosis, thereby facilitating intervention and management if necessary. https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/view/2466 https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/download/2466/1110