BACKGROUND Pulmonary alveolar proteinosis (PAP) is a rare disease characterised by accumulation of lipoproteinaceous material within alveoli, occurring in three clinically distinct forms: congenital, acquired and secondary. Among the latter, lysinuric protein intolerance (LPI) is a rare genetic disorder caused by defective transport of cationic amino acids. Whole Lung Lavage (WLL) is currently the gold standard therapy for severe cases of PAP. CASE PRESENTATION We describe the case of an Italian boy affected by LPI who, by the age of 10, developed digital clubbing and, by the age of 16, a mild restrictive functional impairment associated with a high-resolution computed tomography (HRCT) pattern consistent with pulmonary alveolar proteinosis. After careful assessment, he underwent WLL. CONCLUSION Two years after WLL, the patient has no clinical, radiological or functional evidence of pulmonary disease recurrence, thus suggesting that WLL may be helpful in the treatment of PAP secondary to LPI.