Pulmonary capillary hemangiomatosis (PCH) is a rare condition which causes severe pulmonary hypertensive disease. There are overlapping features with other conditions, particularly pulmonary veno-occlusive disease (PVOD), adding to the difficulty with early suspicion and diagnosis of this disorder. Our case illustrates the value of including PCH in the differential diagnosis of unexplained pulmonary hypertension.
KB is a 35 year old man referred to UAB for lung transplant evaluation. 18 months prior to referral this previously healthy man was admitted to a local hospital with acute dyspnea. Chest radiograph revealed a diffuse, bilateral reticulonodular pattern. Supplemental oxygen, antibiotics, and nebulizer therapy were begun. With only minimal improvement, evaluation continued including a 2-D echocardiogram revealing pulmonary artery systolic pressures above 90 mm Hg. Open lung biopsy demonstrated “microemboli consistent with veno-occlusive disease.” After learning this information, KB recalled that his father and two maternal aunts had pulmonary hypertension. A thorough search for a source of emboli was unsuccessful. KB was treated with warfarin, inhaled beta-agonists, inhaled steroids, and epoprostenol therapy prior to referral. After transfer and lung transplant procedure, surgical pathology reported impressive capillary proliferation in the pulmonary interstitium of the ex-plant. The proliferation impinged on small airways and blood vessels, consistent with the diagnosis of PCH.
PCH involves capillary proliferation within: 1) alveolar septa, 2) bronchial and venous walls, 3) pleura, and sometimes 4) regional lymph nodes . Both clinical presentation and histologic features have similarities with PVOD. Patients usually present with progressive dyspnea, often with pleuritic chest pain and hemoptysis. Chest radiographs usually show a diffuse, bilateral, reticulonodular interstitial pattern. Examination of vasculature often reveals enlarged pulmonary arteries on chest radiograph. Histologically, PCH manifests as capillary proliferation in the areas noted above. There are many similar histologic features between PCH and PVOD, with two distinct difference being capillary growth into the bronchial and venous walls (occurring in PCH but not PVOD) and occlusion of the pulmonary vein lumen occurring more often in PVOD. Although potential therapies include medications such as doxycycline  and interferon alpha-2a  which disrupt capillary growth, only bilateral lung transplant currently offers potential long-term survival. Prostacyclin therapy is considered contra-indicated secondary to a reported risk of pulmonary edema . Interestingly, a hereditary form of PCH has been reported .
PCH is a rare disorder causing significant pulmonary hypertension. It both clinically and histologically resembles PVOD, and clinical suspicion along with close histologic examination is required for differentiation. Consideration of this diagnosis is vital when evaluating a patient with pulmonary hypertension, particularly when investigation of another etiology such as PVOD yields conflicting findings as it did with KB. Diagnosing PCH allows for early evaluation for bilateral lung transplantation, avoidance of prostacyclin therapy, and potential family genetic counseling.
D. Bedsole, None.