Pulmonary disease caused by Mycobacterium avium complex (MAC) represents an increasing complication in patients with bronchiectasis. Its diagnosis requires clinical, radiological, and microbiological integration, posing a challenge for Primary Care (PC) in differentiating between colonization and active infection.A 74-year-old man, non-smoker, with a 25-year history of thoracic trauma resulting in residual bronchiectasis. In 2017, he had pneumonia with MAC isolated in bronchoalveolar lavage (BAL), considered sample contamination and left untreated. Since then, he remained asymptomatic except for a 20-kg weight loss, maintaining an active lifestyle without cough or dyspnea. He presented with isolated hemoptoic sputum preceded by fever, causing concern for himself and family. Physical exam, blood tests and chest radiograph in PC were normal. Given the history and symptoms, after empirical levofloxacin, he was referred to Pulmonology for a full radiological study. Chest CT scan showed cylindrical bronchiectasis in the lingula and middle lobe, with multilobar centrilobular nodules, some cavitary, and peribronchovascular and subpleural consolidations bilaterally. A low-attenuation mass (35×20 mm) was noted in the right lower lobe. Bronchoscopy with culture confirmed Haemophilus parainfluenzae and repeated isolation of MAC with positive auramine staining, ruling out tuberculosis and resistant mutations. The diagnosis of pulmonary MAC disease was confirmed, dismissing the prior contamination assumption. He began a thrice-weekly regimen of azithromycin, ethambutol, and rifampicin. Under PC follow-up with close Pulmonology coordination, he continues to be monitored for clinical evolution and drug tolerance.This case is notable for absence of classic risk factors, post-traumatic bronchiectasis, and early diagnostic uncertainty.Longitudinal assessment in PC is vital to detect clinical and radiological progression. Continuous education and close collaboration with other specialists optimize outcomes in complex cases.Pulmonary MAC disease in the context of bronchiectasis poses a diagnostic challenge for primary care due to difficulty in differentiating colonization from active infection. This case illustrates how close collaboration with Pulmonology and integration of clinical, radiological, and microbiological data are essential for proper diagnosis and management.Ongoing evaluation and interdisciplinary collaboration fortify PC's role in managing pulmonary MAC disease, emphasizing patient-centered care and shared decision-making for improved outcomes.