Early-onset gastrointestinal amyloid A amyloidosis without renal involvement in a patient with RA–pSpA overlap: A case report

Rationale: Amyloid A (AA) amyloidosis involving the gastrointestinal (GI) tract is a rare but potentially life-threatening complication of chronic inflammatory rheumatic diseases. Although typically associated with long-standing rheumatoid arthritis (RA), it is rarely reported in the context of RA–peripheral spondyloarthritis (pSpA) overlap syndrome. We report a rare case of early-onset GI-predominant AA amyloidosis without renal involvement in a patient with overlapping RA and HLA-B27–positive pSpA. Patient concerns: A 52-year-old male presented with progressive arthritis involving the knees, ankles, and toes. Despite RA treatment, inflammatory markers remained elevated. He later developed anterior uveitis and gastrointestinal symptoms including abdominal pain and diarrhea. Diagnoses: He fulfilled classification criteria for both RA and pSpA. Endoscopic biopsy revealed amyloid A deposits in the stomach and duodenum. Interventions: Intravenous tocilizumab was initiated every 4 weeks. Outcomes: After 2 months of tocilizumab treatment, GI symptoms markedly improved, inflammatory markers and serum albumin normalized, and imaging demonstrated resolution of bowel wall edema. Serum amyloid A levels also markedly decreased to within the normal range. The patient achieved sustained remission of articular and gastrointestinal manifestations at 6-month follow-up. Lessons: This case illustrates early GI-dominant AA amyloidosis without renal involvement in RA–pSpA overlap. The coexistence of intense inflammatory responses and mucosal immune activation may predispose the GI tract to early amyloid deposition, emphasizing the need for active surveillance and early endoscopic evaluation in patients presenting with unexplained GI symptoms.