Amyloid A Amyloidosis Secondary to Thymoma

<b>Background:</b> Amyloid A (AA) amyloidosis is commonly secondary to chronic inflammatory diseases or malignant neoplasms. Many types of cancers have been described as inducing AA amyloidosis, usually presenting with kidney involvement. However, there are no reported cases of concurrent thymoma and AA amyloidosis. <b>Case Presentation:</b> We describe a 52-year-old male presenting chest tightness. Through a series of examinations, the patient was ultimately confirmed to have AA amyloidosis secondary to thymoma, with kidney, cardiac, nerve, and soft tissue involvement. <b>Conclusions:</b> This case represents, to our knowledge, the first reported case of systemic AA amyloidosis occurring secondary to thymoma. It highlights thymoma as a potential underlying cause of AA amyloidosis, likely due to a chronic inflammatory response driven by the tumor. This association complicates clinical management and prognosis, requiring a heightened awareness of amyloidosis in thymoma patients who present with unexplained multi-organ dysfunction.