Pleuroparenchymal Fibroelastosis of the Lung: A Review

Described in Japan by Amitani et al in 1992, the entity of idiopathic upper lobe fibrosis was subsequently given the name pleuroparenchymal fibroelastosis (PPFE) in the English-speaking world. Pleuroparenchymal fibroelastosis is believed to be a rare disease characterized by a fibrosing process affecting the pleura and the subpleural lung parenchyma, with a predilection for the upper lobes. Uniquely, the fibrosing process is elastotic in nature, being associated with intra-alveolar fibrosis. The etiology of PPFE is unclear at this juncture, with many cases being considered as idiopathic forms of the disease. Conditions associated with PPFE include infections, bone marrow transplantation, and autoimmunity. In this review, we explore the clinical, radiologic, and pathologic features associated with PPFE in light of current understanding of the disease. Recent studies implicated that PPFE may not be as uncommon as claimed. The various differential diagnoses and implications of diagnosing PPFE are discussed.