Pulmonary actinomycosis mimicking lung cancer on 18F-fluorodeoxyglucose positron emission tomography: a case report

Abstract

Background Pulmonary actinomycosis is a chronic disease characterized by abscess formation, draining sinuses, fistulae, and tissue fibrosis. It can mimic other conditions, particularly malignant and granulomatous diseases, and is perhaps extremely challenging to diagnose. Case presentation A 64-year-old Japanese man presented with 6-week history of a painful solid lump in the chest wall. Chest computed tomography scan revealed a mass-like consolidation in the left upper lobe, with rib erosion and direct extension into the anterior chest wall. 18F-fluorodeoxyglucose positron emission tomography scan showed increased metabolic activity in the mass, which is indicative of primary lung cancer. The bronchoscopy and computed tomography scan-guided transthoracic biopsy results were considered nondiagnostic. Finally, the patient was diagnosed with pulmonary actinomycosis via surgical resection. He completed an 8-week course of antibiotic therapy and experienced no recurrence. Conclusions There is no difference in positron emission tomography/computed tomography scan findings between actinomycosis and malignancy. Therefore, pulmonary actinomycosis should be considered in the differential diagnosis of cases involving intensive activity on 18F-fluorodeoxyglucose positron emission tomography scan.

Detection of pulmonary actinomycosis by metagenomic next-generation sequencing in a cancer patient receiving maintenance olaparib: A review and case report

“…Moreover, the low specificity of radiological features poses a diagnostic challenge as various CT findings have been observed, such as alveolar or lobar consolidation, pleural thickening or effusions, ground-glass opacities, and necrotic mass [ 12 ]. Many cases might be confused with lung abscess, tuberculosis, lung malignancy, and fungal infection (e.g., Aspergillosis) [ [13] , [14] , [15] ]. However, the actinomycosis should be immediately diagnosed as the reported mortality rates vary between 0 and 28% [ 10 ].…”