Overlapping lung parenchymal and bronchial lesion and hilar lymphadenopathy in pulmonary actinomycosis mimicking lung cancer

Abstract

DESCRIPTIONA 43-year-old man with a 9-year history of schizophrenia presented with productive cough, and was diagnosed with pneumonia of the left lung. As treatment with clarithromycin followed by garenoxacin was not effective, the patient was referred to our hospital. Although physical examination was unremarkable, chest X-ray and enhanced CT showed an irregular-shaped mass in the left inferior lobe, with airway stenosis of the lobar bronchus due to wall thickness and hilar lymphadenopathy (figure 1A-C). The bronchoscopic view of swollen mucosa with nodules was compatible with lung cancer mucosal invasion ( figure 2A, B). However, mucosal biopsies revealed tiny clumps including filamentous branching of the bacteria with radial arrangement surrounded by inflammatory cells ( figure 2C) and food residues. These pathological findings were compatible with endobronchial actinomycosis. The patient was treated with parenteral ampicillin (6 g/day) for 1 month, followed by oral amoxicillin (1.5 g/day) for 5 months. After the antibiotic treatment, chest CT showed disappearance of the mass shadow, airway stenosis and hilar lymphadenopathy.The patient had many risk factors for pulmonary actinomycosis, such as pre-existing dental disease, poor oropharyngeal hygiene and smoking.

Pulmonary actinomycosis: cytomorphological features

“…While pulmonary actinomycosis can clinically mimic other pulmonary infections (e.g. nocardiosis, aspergillosis, tuberculosis) or even malignancy [24,[29][30][31][32][33], it is important to be aware that co-infections with other microorganisms creating lung masses have also been described [34][35][36][37]. Aspiration of oropharyngeal secretions or the presence of a foreign body in the bronchial tree seems to be the main cause of pulmonary actinomycosis.…”