Un taux de procalcitonine sérique déroutant

Procalcitonin (PCT) is a marker of severity of sepsis, whose absolute value and kinetics are correlated to the severity of the infection. We here report the case of a 55-yer old patient admitted to Rheumatology with feverish hyperalgesic lombosciatalgies. He had very high PCT level without any correlation with sepsis. Laboratory tests showed neutrophilic hyperleukocytosis at 15000 Item/mm3 associated with CRP and PCT serum at 305 mg/l and 2,5ng/ml respectively. Given this suggestive sepsis presentation, bloodcultures were performed and probabilistic antibiotic treatment was introduced. MRI of dorsolumbar spine was performed due to the absence of favorable outcome of patient as well as the discrepancy between PCT levels which were very high and negative blood cultures. MRI showed arthritis in right hip associated with multiple secondary bone lesions of the axial skeleton of supposed neoplastic origin. Thoraco-abdominopelvic CT scan showed left lung mass. Lung biopsy showed an infiltrating adenocarcinoma.