Cytopathological examination of bronchoalveolar lavage fluid in diagnosis of pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is a rare disease characterized by the deposition of extracellular lipoproteinaceous material within the air spaces. Although the diagnosis is mainly based on histopathological findings, sometimes, the diagnostic yield of transbronchial and even open lung biopsy can be unsatisfactory. The advantage with bronchoalveolar lavage (BAL) cytology is that apart from being safer for the patient, it can sample a much wider area and help in giving an early diagnosis and treatment to the patient. Herein, we present a case of PAP diagnosed on BAL fluid cytology in an elderly female.