Hermansky-Pudlak syndrome-associated interstitial pneumonia: Pathologic and imaging findings

Initially described in 1959, Hermansky-Pudlak syndrome (HPS) is an autosomal recessive disorder characterized by tyrosinasepositive oculocutaneous albinism with a bleeding diathesis. To date, 9 genes have been associated with HPS. The pathogenesis of HPS is thought to be due to disruption in the formation and trafficking of intracellular vesicles including melanosomes, platelet dense granules in platelets, and lysosomes. Late internal manifestations result from the liposomal accumulation of ceroid lipofuscin in macrophages in the lungs, heart, kidneys, and intestines. Hermansky-Pudlak syndrome has an estimated worldwide prevalence of 1:500,000 to 1:1,000,000. However, in Puerto Rico, HPS is the most prevalent single gene disorder with a prevalence as high as 1:1800. Hermansky-Pudlak syndrome typically has a poor prognosis; mortality is usually due to pulmonary fibrosis, which typically manifests in the third to fourth decades with death within a decade.