Paraneoplastic syndrome mimicking adult-onset Still's disease caused by advanced lung cancer: a case report.

Background: Paraneoplastic syndromes (PNSs) are common complications of lung cancer and often develop preceding the diagnosis of primary malignancy. Rheumatologic PNSs mimicking Adult-Onset Still' s Disease (AOSD) is a rare condition with only a limited number of cases reported in the literature, none of which was associated with lung cancer. It is often difficult to differentiate AOSD-like paraneoplasia from coincidental AOSD based on the clinical manifestations.

Case Presentation: Here we present a 56-year-old man with advanced lung adenocarcinoma who developed a remittent fever together with pharyngodynia and joint pain after first cycle of chemotherapy with paclitaxel plus carboplatin. Although a leukocytosis was detected, no evidence of infection was acquired and empirical antibiotic treatment was ineffective. A temple skin rash, abnormal hepatic function and a remarkable elevated level of serum ferritin occurred later in this patient, which highly supported a potential diagnosis of AOSD. The patient was finally diagnosed as AOSD-like PNS considering the good and prompt response to a short-term administration of non-steroidal anti-inflammatory drug and subsequent cycles of effective chemotherapy with pemetrexed plus cisplatin.

Discussion And Conclusions: Though rare, AOSD-like PNS can be one of the potential diagnoses in lung cancer patients with fever of undetermined origin, especially those having no response to antibiotic treatment. Management consists of control of the underlying malignancy and symptomatic treatment of the syndromes with non-steroidal anti-inflammatory drugs or corticosteroids.