ABSTRACT Amyloid fibrils aggregate and deposit in many tissues and multiple organs, leading to systemic amyloidosis. One of the main forms of systemic amyloidosis is called amyloid A (AA) amyloidosis, where chronic inflammation causes the serum amyloid A (SAA) protein to transform into a precursor protein. Regarding the etiology of AA amyloidosis, it was noted that inflammatory arthritis, such as rheumatoid arthritis, was the most common underlying pathology and that malignant disease was one of the uncommon causes. Amongst the malignant causes, the common carcinomatous etiology of amyloidosis has been identified as renal cell carcinoma (RCC). We report a case of incidental detection of ipsilateral renal and adrenal gland AA amyloidosis with RCC in a patient who died 10 days after surgery due to sepsis and multiorgan failure. A 65-year-old female who presented with weight loss, haematuria, left loin pain, severe fatigue, anemia, and facial puffiness for 4 weeks before admission. An ultrasonography (USG) of the abdomen and pelvis revealed a well-encapsulated mass lesion involving the anteromedial aspect of the upper pole of the left kidney, with the possibility of a malignant mass lesion. On histopathology, it was a clear cell RCC with adjacent renal parenchyma and adrenal gland showing amyloid deposits, which showed apple green birefringence on the polariser. These deposits were positive for serum amyloid A on immunohistochemistry (IHC). Thus, renal cell carcinoma, amongst solid organ malignancies, can be the most common cause of systemic amyloidosis.
Khushbu et al. (2026) studied this question.