Clinical impact and prognostic implications of concurrent amyloid deposition in patients with POEMS syndrome: A single-center retrospective study.

POEMS syndrome is a rare paraneoplastic disorder driven by an underlying monoclonal plasma cell clone. A subset of patients develops concomitant amyloid deposition; however, the associated clinical profile and prognostic implications remain poorly defined. We retrospectively analyzed 62 patients with POEMS syndrome treated at Tongji Hospital between January 2018 and May 2025, comparing those with POEMS alone (n = 55) and those with biopsy-proven concurrent amyloid deposition (n = 7). Compared with POEMS-only patients, those with concurrent amyloid deposition were older (median 62 vs. 53 years; p = 0.022) and had higher IgA (6.21 vs. 2.17 g/L; p = 0.034) and λ free light chains (127.0 vs. 35.4 mg/L; p < 0.001). They also showed a more pronounced cardiac phenotype, including higher NT-proBNP (1250 vs. 359 pg/mL; p = 0.009) and hs-cTnI (47.4 vs. 2.1 pg/mL; p = 0.002), greater left ventricular wall thickness, and lower tissue Doppler velocities. Responses appeared numerically lower in patients with concurrent amyloid deposition, and overall survival was inferior compared with POEMS-only. In POEMS syndrome, biopsy-proven concurrent amyloid deposition marks a higher-risk phenotype characterized by disproportionate cardiac involvement and worse survival. These findings highlight the importance of clinical vigilance, careful evaluation for coexisting amyloid deposition, and multidisciplinary management.