Cancer polyarthritis resembling rheumatoid arthritis as a first sign of hidden neoplasms. Report of two cases and review of the literature.

Recent onset arthritis reminiscent of rheumatoid arthritis (RA) may be an early manifestation of an occult malignancy. In this report, we present two patients with cancer-associated polyarthritis. Both suffered from symmetric polyarthritis when initially visiting their physicians and did not achieve relief when treated with non-steroidal anti-rheumatic drugs (NSAIDs). In both patients, subsequent work-up led to the diagnosis of an underlying malignancy. One patient suffered from small cell lung cancer (SCLC), while the other was diagnosed with adenocarcinoma of the colon. In both, the arthritis spontaneously disappeared after successful treatment of the malignancy, i.e. chemotherapy and tumor resection, respectively. We discuss these cases in view of the existing literature, since awareness of the entity of cancer polyarthritis is necessary for its timely treatment and may potentially be life-saving.