Reactive (AA) Amyloidosis in a 14 Year Old with No Predisposing Disease

Abstract

Reactive (AA) amyloidosis usually occurs in relation to chronic inflammation or infection. It also occurs in individuals with familial Mediterranean fever (FMF) and occasionally in asymptomatic individuals within FMF kindreds. Infrequently, adults present with AA amyloidosis without predisposing disease, but such cases are extremely rare in children. We report the case of a 13 year old Caucasian male who presented with weakness, lethargy, and an abdominal mass. Resection of the mass revealed mesenteric lymph nodes heavily infiltrated with amyloid. Liver, gastric, duodenal, and rectal biopsies were positive for amyloid. Immunohistochemistry of the resected lymph nodes with monoclonal antibody to human AA was positive. Amyloid fibrils isolated from the nodes were solubilized, fractionated, and digested with trypsin. Amino acid sequence analysis of tryptic peptides confirmed the AA structure with predominance of SAAl-derived AA. Complete patient history and physical exam elicited no evidence of infection, inflammation, or family history of FMF type illness. We report this as a case of spontaneous reactive (AA) amyloidosis in the pediatric age group.