ACTINOMYCOSIS MIMICKING LUNG CANCER: A CASE REPORT

Abstract

SESSION TITLE: Medical Student/Resident Chest Infections Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Pulmonary actinomycosis is a rare disease that can be challenging to diagnose and is associated with multiple risk factors such as poor oral hygiene, alcoholism, and chronic underlying lung diseases. Actinomycosis can often be misdiagnosed as lung abscess, tuberculosis, or malignancy with radiologic findings that might be misleading. Here we present a case with initial chest CT finding concerning neoplasm but diagnosed as pulmonary actinomycosis on further evaluation. CASE PRESENTATION: 55-year-old male with past medical history of HTN presented with right sided upper back pain and 6 pounds of unintentional weight for 4 weeks. He did not report any symptoms of cough, hemoptysis, shortness of breath, or chest pain. He was a heavy smoker with 45 pack years of smoking and a history of chronic alcoholism with 30 ml of 3-4 vodka shots twice a week for the last 30 years. Patient’s laboratory studies were pertinent for WBC count of 19.6 X 10 3. CT of the chest showed 4.6 x 3.4 cm thick-walled cavitary mass in the right lower lobe concerning for neoplasm with the extension of mass to the right paravertebral region and diffuse right pleural metastases, pathologic lymphadenopathy, and trace right pleural effusion. He underwent BAL with bronchial brushing which showed significant endobronchial inflammation. Microbiological examination of samples obtained from BAL showed Gram-positive filamentous bacteria. Treatment was given with IV clindamycin and he was discharged home on PO Clindamycin for 4 weeks with a repeat chest X-ray in 2 weeks. He was readmitted after 2 weeks with worsening shortness of breath, was found to be hypoxic with SpO2 of 65% on RA and RR of 40/min, he was intubated. Repeat CT chest showed diffuse right pleural thickening and ground-glass opacity of the right upper and middle lung. He was started on broad-spectrum antibiotics with IV vancomycin, IV Zosyn and IV Penicillin but he remained critically ill and a decision was made by the family to withdraw care. The patient was terminally extubated. DISCUSSION: Actinomycosis is a chronic, granulomatous disease mostly caused by A. israelii which is a normal commensal of human oropharynx, GI tract, and female genitalia. Pulmonary actinomycosis accounts for 15% of total disease burden and is usually caused by aspiration of the oropharyngeal or gastrointestinal secretion especially in patients with chronic alcoholism and poor dentition, facial or dental trauma1. CONCLUSIONS: Diagnosis of actinomycosis can be challenging given that presentation and radiologic findings might resemble various other conditions. Pulmonary actinomycosis if diagnosed and treated early has an excellent prognosis, the clinician should have high levels of suspicion in patients with risk factors such as chronic alcoholism, poor dental hygiene, prompting further evaluation with radiology and confirmation of diagnosis with histology and microbiology. Reference #1: 1. Mabeza GF, Macfarlane J. Pulmonary actinomycosis. Eur Respir J. 2003;21(3):545-551. doi:10.1183/09031936.03.00089103 DISCLOSURES: No relevant relationships by Sotirios Doukas, source=Web Response No relevant relationships by Leena Kavali, source=Web Response No relevant relationships by Shashank Nuguru, source=Web Response