Pulmonary Veno-occlusive Disease and Pulmonary Capillary Hemangiomatosis

Abstract

Pulmonary veno-occlusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH) are two unusual idiopathic disorders that almost uniformly manifest to the clinician as pulmonary arterial hypertension (PAH). Impressive clinical signs and symptoms often obscure the true underlying capillary or postcapillary disorder, thus severely compromising timely and appropriately directed therapy. The hemodynamics of PVOD and PCH are the consequence of a widespread vascular obstructive process that originates in either the alveolar capillary bed (in cases of PCH) or the pulmonary venules and small veins (in PVOD). Since the earliest descriptions of PVOD and PCH, there has been a debate as to whether these are two distinct diseases or varied expressions of a single disorder. The cause of PVOD or PCH has not yet been identified, although there are several reported associations. Without curative lung or heart-lung transplantation, patients with these conditions face inexorable clinical deterioration and death within months to a few short years of initial presentation. Surgical lung biopsy is the definitive diagnostic test, but it is a risky undertaking in such critically ill patients. The imaging manifestations of PVOD and PCH often reflect the underlying hemodynamic derangements, and these findings may assist the clinician in discerning PAH from an underlying capillary or postcapillary process with findings of septal lines, characteristic ground-glass opacities, and occasionally pleural effusion.

Pulmonary Capillary Hemangiomatosis: A Rare Cause of Pulmonary Hypertension

“…Alveolar lavage frequently shows increased hemosiderin-laden macrophages. 3,8,10,11 In the 2003 Venice clinical classification of pulmonary hypertension, 12 PCH was included with PVOD as a subtype of pulmonary arterial hypertension based on the involvement of venules or arterioles seen in both entities. In the most recent classification system, the 2008 Dana Point revision, 12 PCH and PVOD are placed in their own category, group 1 0 , which is closely related to but distinct from the pulmonary arterial hypertension group (Table).…”

“…Radiographic findings are typically nonspecific and include changes consistent with pulmonary hypertension (bilateral interstitial infiltrates, cardiomegaly, and enlargement of the pulmonary arteries 10,11 ). Depending on the extent of disease, diffuse bibasilar reticulonodular or micronodular areas of opacity can be seen.…”

“…This finding in addition to lymphadenopathy is thought to be more suggestive of PCH as opposed to PVOD, although discrimination between these entities is generally not possible based solely on imaging studies. 3,11 On computed tomography scan, the hallmark of welldeveloped PCH is diffuse centrilobular ground-glass nodular opacities. 5,8,11 The periphery is generally spared, and the distribution of lesions is typically bilateral and involving all lobes.…”

“…3,11 On computed tomography scan, the hallmark of welldeveloped PCH is diffuse centrilobular ground-glass nodular opacities. 5,8,11 The periphery is generally spared, and the distribution of lesions is typically bilateral and involving all lobes. As on radiography, changes associated with pulmonary hypertension are also present.…”

“…3,8,11,13 Other less specific findings include a congested and edematous appearance without significant fibrosis.…”