The authors report the results of lung scintigraphy in two patients with primary pulmonary hypertension caused by pulmonary capillary hemangiomatosis, a rare disorder resulting from the proliferation of histologically normal capillaries in the lung. Perfusion studies revealed a nonhomogeneous pattern with some focal defects, similar to that seen with some other histologic types of primary pulmonary hypertension. The mechanisms underlying this reperfusion pattern are unknown.