Amyloidosis of submandibular lymph node masquerading as a salivary gland tumor: A rare case report with review of literature

Amyloidosis is a disease characterized by the extracellular deposition of fibrillary proteins causing organ dysfunction. Submandibular lymphadenopathy is a rare clinical presentation of amyloidosis. Majority of the patients progress to develop systemic diseases and usually have AL amyloidosis. Here, we report a case of a 40-year-old male, who presented with a left submandibular swelling for 3 years. The clinical diagnosis was malignant submandibular salivary gland tumor. Systemic examination was unremarkable. Histopathological examination of the excised swelling revealed effacement of lymph node architecture by an eosinophilic Schiff poor material. Positive Congo red stain with apple-green birefringence on polarization confirmed it as amyloidosis. Serum protein electrophoresis was negative for M Band. Immunohistochemistry revealed kappa light-chain restriction in the deposits, characterizing it as localized primary amyloidosis of the submandibular lymph nodes.