Systemic AA amyloidosis in a patient with lung metastasis from renal cell carcinoma

Abstract

AA amyloidosis occurs in patients with high levels of serum amyloid A protein (SAA), which is produced by liver cells in response to signals from several pro-inflammatory cytokines. Chronic inflammatory disease is a major cause of AA amyloidosis; however, malignant neoplasms are rarely reported to be associated with AA amyloidosis. We report herein a case of a solitary lung metastasis of renal cell carcinoma associated with systemic AA amyloidosis. Pathological specimens of the resected lung tumor demonstrated renal cell carcinoma, and the presence of IL-1β, IL-6, and TNF-α in the lymphocytes and plasma cells surrounding the tumor cells, and AA amyloid in the vascular area, but not in metastatic clear cells. Four weeks after surgery, serum IL-6, SAA, and CRP levels normalized. Although this case is very rare, it is full of interesting suggestions about the pathogenesis of malignancy-related systemic amyloidosis.

Keywords::

• IL-1β
• IL-6
• renal cell carcinoma
• SAA
• solitary metastatic lung tumor
• systemic AA amyloidosis
• TNF-α

Declaration of Interest: The authors declare no conflict of interest. The authors were supported by a grant from the Amyloidosis Research Committee of the Intractable Diseases Division in the Ministry of Health, Labour and Welfare of Japan.