A case of pulmonary actinomycosis mimicking chronic necrotizing pulmonary aspergillosis

Abstract A 60-year-old man was admitted to our hospital with fever, appetite loss, and fatigue. Chest X-ray films and computed tomography scans showed fungus-ball-like lesions in the thoracic cavity, and pleural thickening with surrounding infiltration in the left upper lobe, developing over several months. The white blood cell count (WBC) and serum C-reactive protein (CRP) levels of the patient at the time of admission were 8800/microl and 2.7 mg/dl, respectively. He showed a negative reaction for the serum Aspergillus precipitating antibody, and a positive reaction for the serum Aspergillus antigen (Pletelia Aspergillus) according to the new cut-off index (the result was 0.8). From these clinical findings, we diagnosed this lesion as chronic necrotizing pulmonary aspergillosis (CNPA) and administered anti-fungal drugs (itraconazole plus micafungin, voriconazole) for several months. Despite medication, his condition appeared to deteriorate, and Aspergillus was never confirmed from frequent sputum cultures and bronchial lavage specimens. Finally, a pneumectomy was performed. Histopathological findings revealed a Gram-positive, filament-form Actinomyces cluster inside the cavity, which we diagnosed pulmonary actinomycosis. In this case, there was a possibility that the serum aspergillus antigen showed a false-positive reaction. Case must be taken in the evaluation of serum Aspergillus antigen testing.