Necrotizing pulmonary granulomata in a marijuana smoker

We describe the case of a heavy marijuana and tobacco smoker who presented with progressive exertional dyspnea of 2 months' duration, and bilateral nodular lung infiltrates. Examination of the lung fields was normal, and lung function tests showed mild airflow obstruction with moderately reduced gas transfer. BAL returned green-black fluid consisting predominantly of macrophages laden with carbon pigment. Thoracoscopic lung biopsy showed miliary necrotizing granulomata with an alveolar exudate of carbon-laden macrophages within macroscopically blackened lung. The differential diagnosis of pulmonary granulomata in this patient is discussed.