Pulmonary capillary hemangiomatosis incidentally detected in a lobectomy specimen for a metastatic colon cancer

Pulmonary capillary hemangiomatosis is a rare vascular proliferative disease of unknown etiology. The common clinical features are slowly progressive and finally fatal pulmonary hypertension. The clinical diagnosis is usually difficult. Because most reported cases are of autopsy, little is known about its incipient lesion and natural history. Presented herein is a case of pulmonary capillary hemangiomatosis incidentally detected in a surgically resected lung for a metastatic colon cancer. The patient was a 60‐year‐old Japanese woman with a history of sigmoid colon cancer 3 years previously. The patient had undergone a right lower lobectomy for a metastatic tumor in the hilar region and a thoracoscopic tumorectomy of the peripheral area of the left upper lobe. Except for an episode of hemoptysis 2 weeks prior to the lung surgery, there were no other clinical symptoms characteristic of pulmonary capillary hemangiomatosis. The non‐tumor area of right lower lobe showed multiple foci of capillary proliferation affecting alveolar walls, interlobular septa and pleura associated with patchy hemorrhage. There was a minor degree of vascular and bronchial involvement by capillary proliferation. It is suggested this particular case is an incidentally detected clinically incipient stage of pulmonary capillary hemangiomatosis. Passive congestion secondary to metastatic colon cancer in the hilar region may have contributed to the pathogenesis of this lesion.