Introduction: Alveolar Macrophage Pneumonia (AMP) is an uncommon smoking-related interstitial pneumonia with generally favorable prognosis, although some patients may experience disease progression and adverse outcomes.
Objectives: To characterize patients with AMP and evaluate the impact of smoking cessation and corticosteroid therapy on disease progression and long-term functional outcomes.
Materials and Methods: We conducted a retrospective case series of biopsy-proven AMP patients followed at a pulmonology outpatient clinic in Portugal (01/2015–01/2026). Patients with follow-up <12 months or insufficient histological data were excluded, and clinical, demographic, radiological, and treatment data were analyzed.
Results: 37 patients were included; 70.3% were male, median age 58 years [53–65]. Most were current (81.1%) or former smokers (16.2%), and 19.4% had autoimmune disease. Dyspnea and cough were the main symptoms, while ground-glass opacities were the predominant CT finding, often associated with emphysema; 13.8% had fibrosis at diagnosis. Corticosteroids were administered to 13 patients (35.1%) for a median of 16 months [6–30]; four required additional immunosuppression and three received antifibrotic therapy. The corticosteroid group had lower baseline median FVC (95.7 vs 116.9, p=0.008). Treatment was mainly initiated due to respiratory symptoms with functional and/or radiological deterioration. Among active smokers, 30% achieved smoking cessation, and corticosteroid use was less frequent in quitters than in persistent smokers (22.2% vs 47.6%). Baseline median FVC was lower in active smokers requiring corticosteroids (89.7% vs 108.8%). Median FVC decline at 5 years was similar between quitters and persistent smokers (−4.4% vs −7%), but among persistent smokers, decline was greater without corticosteroids (−18.9% vs +1.5%). After a median follow-up of 7.3 years [5.2–10.1], 13.5% developed chronic respiratory failure and four patients died (two from lung cancer).
Conclusions: Corticosteroid therapy appeared to improve functional outcomes, while the impact of smoking cessation remained unclear, likely due to the small sample size. AMP showed a variable prognosis, highlighting the need for individualized management and long-term follow-up.