Cavernous hemangioma of the lung is one of the rarest lesions. The association of this condition with compensatory polycythemia has been reported in only 4 cases in medical history. The case reviewed in this paper was the first in more than 240,000 admissions at the University of Chicago Clinics in the last fifteen years, and more than 4,380 autopsies at the same institution did not reveal another such lesion. In 1942 Hepburn and Dauphinee1 reported the first case in which hemangioma of the lung was diagnosed from clinical and laboratory information and in their discussion included a review of the literature. Their case was also the first one reported in which a cure was obtained following total pneumonectomy.2 Ten cases of hemangioma of the lung reported in the literature are given in table 1, in 5 of which the hemangiomas may be rated definitely as cavernous (cases 5,