INTRODUCTION: Non Tuberculous Mycobacteria (NTM) is ubiquitous to the environment, and its pulmonary manifestations can vary from colonization to hypersensitivity pneumonitis to advanced fibrocavitary disease. Many patients with NTM are immunosuppressed or have an underlying lung disease. The most common associated conditions include COPD, old TB/fungal disease, bronchiectasis, silicosis, cystic fibrosis, and AIDS.
CASE PRESENTATION: A 32 year-old man with no significant past medical history presented with 2 weeks of productive cough and right sided chest pain. He denied hemoptysis, fever, weight loss, night sweats, or shortness of breath. The patient worked as a machine operator. He denied recent travel, TB exposure, or having exotic pets at home. He smoked 1 1/2 packs of cigarettes per day for the past 16 years, and he rarely drank alcohol. Chest exam was normal and no other significant abnormalities were detected on physical exam. Chest X ray and CT scan revealed a 5 cm x 5 cm thick-walled cavity in the superior segment of the left lower lobe. The wall measured approximately 20 mm. Diffuse “tree-in-bud” appearance was present in the right middle lobe and the lingula. PPD and HIV test were negative. Sputum acid fast bacillus (AFB) smear was 3+ positive in 3 consecutive daily samples. AFB culture revealed Mycobacterium Avium Complex. Treatment with Ethambutol, Rifampin, and Azithromycin was initiated. Four weeks later, he complained of left sided headache. He had night sweats but was afebrile. He also complained of right sided flank pain without radiation or hematuria. Physical exam was otherwise negative. CT and MRI of the brain showed multiple lesions in the frontal and occipital lobe. Lumbar puncture revealed malignant cells. Bronchoscopy with transbronchial biopsies of the left lower lobe revealed adenocarcinoma.
DISCUSSIONS: Lung cancer by itself in a 32-year-old man is unusual, but this patient was diagnosed during treatment for cavitary NTM. There were many diagnostic pitfalls and management challenges that characterized this case. First, this patient had no apparent risk factors for cavitary MAC, but he did have a significant risk factor for lung cancer (16 pack year smoking). Second, the thickness of the cavitary wall was a sign that this may be more than simply mycobacterial infection. In a study of 65 solitary lung cavities, when the wall was over 15 mm in thickness, 92% of the lesions were malignant. (1).
CONCLUSION: This case illustrates that in a smoker with thick-walled cavity, cancer may coexist with active infection, and tissue biopsy may be required. Our case also emphasizes the importance of considering lung cancer in younger patients who smoke. The proportion of bronchogenic adenocarcinoma is higher in the young compared with all patients with lung cancer, and younger patients more frequently present with advanced disease at diagnosis, resulting in an extremely poor survival. (2).
DISCLOSURE: Razaq Badamosi, None.