Remitting Seronegative Symmetrical Synovitis with Pitting Oedema as the First Manifestation of an Adenocarcinoma of the Caecum

Remitting seronegative symmetrical synovitis with pitting oedema (RS3PE) is a rare syndrome that affects the elderly. Although the aetiology is not fully understood, it has been related to multiple diseases including cancer. We present the case of an 80-year-old man with a full spectrum of signs and symptoms compatible with RS3PE: sudden onset of bilateral polyarthralgia of the metacarpophalangeal and proximal interphalangeal joints, oedema of the dorsum of the hands, increased inflammatory markers and seronegative rheumatoid factor. After a 5-day course of corticotherapy, the patient became asymptomatic although maintaining a mild anaemia. During a search for the underlying cause of the RS3PE, an early stage adenocarcinoma of the caecum was diagnosed and surgically removed. No further treatment was performed and after 3 years of follow-up the patient remains without evidence of either paraneoplastic RS3PE or cancer. LEARNING POINTS: RS3PE3 is a rare inflammatory syndrome characterized by symmetrical distal synovitis and pitting oedema over the dorsum of the hands and/or feet and seronegative rheumatoid factor. The pathogenesis has not been fully explained although it has been described with multiple diseases including as a paraneoplastic syndrome. Our clinical awareness led to prompt diagnosis of an early stage and curable adenocarcinoma of the caecum.