Aggravation of Nontuberculous Mycobacterial Pulmonary Disease Presenting as Variably Sized Lung Masses

Abstract Introduction Nontuberculous mycobacteria (NTM) are ubiquitous pathogens that cause chronic pulmonary infections. NTM pulmonary diseases are typically classified into fibro-cavitary and nodular-bronchiectatic types based on radiologic patterns. However, NTM can also manifest as pulmonary masses or nodules, mimicking malignancy. We report two cases of NTM pulmonary disease that worsened during treatment, with imaging revealing lung masses of variable sizes. Case presentation A 59-year-old man presented with weight loss over 6 months, general weakness, and hemoptysis. He was a never-smoker with a history of glaucoma. He underwent chest computed tomography (CT) scan which showed centrilobular nodules with branching patterns and focal consolidation in the right middle lobe and lingular segment. Sputum analysis showed positive results for acid-fast bacilli (AFB) smear and culture, identifying Mycobacterium avium. Despite antibiotic treatment, he remained culture-positive. During the fifth year of persistent treatment, the patient reported increased sputum and mild dyspnea. Chest CT revealed newly observed and increased sizes of multiple well-defined masses and nodules in both lungs. A percutaneous needle biopsy was performed on a 35mm x 48mm mass in the left lower lobe, but pathological examination showed only necrotic tissue. AFB stain and Polymerase chain reaction (PCR) for NTM were both negative. The patient is currently undergoing treatment, but the masses continue to grow despite changes in antibiotic regimens. A 69-year-old woman with a history of carotid atherosclerosis presented with hemoptysis. Chest radiograph revealed nodular opacities in right upper lobe. Sputum AFB smear was positive and Mycobacterium abscessus was identified. After two years of treatment, chest CT scan showed an increased number of discrete lung nodules, some with cavitary changes. Additionally, serial chest radiographs demonstrated fluctuations in the sizes of multiple nodules. Despite these findings, the patient did not experience worsening respiratory symptoms. A percutaneous needle biopsy was performed on a 18mm x 20mm nodule in the right lower lobe. Pathological examination revealed chronic granulomatous inflammation with necrosis. Both the AFB stain and NTM PCR from the tissue biopsy returned negative results. The antibiotics were changed, and the lung nodules are generally decreasing in size. Discussion Aggravation of NTM pulmonary disease can manifest as lung nodules and masses of varying sizes, which can wax and wane on serial imaging.Newly detected multiple lung masses during NTM treatment should undergo pathological evaluation to rule out the possibility of malignancy.