Neoplasms of vascular origin in the mediastinum.

INCIDENCE Seybold, McDonald, Clagett, and Harrington (1949) made the f i s t collective review of these tumours, in which they mainly discussed their pathology. They could find only 14 cases, to which they added 3 more cases from the Mayo Clinic. The real incidence of these neoplasms in relation to other mediastinal masses is very difficult to estimate. However, the widening scope of thoracic surgery, together with the increasing use of mass radiological surveys, has led to the discovery and treatment of many such cases. Altogether, 66 cases have been mentioned in the literature. Of these, tumours originating in the pericardium (9 cases) and the cases belonging to the haemangiopericytoma group (3 cases) are discussed separately for convenience. Of the remaining 54 cases, only 34 are included for review in Table I , together with the 3 cases here described, these being the cases which have been reported in sufficient detail. Twenty-one other cases, which were briefly described or referred to by different writers while reviewing their series of mediastinal tumours, are enumerated in Table ZI. The cases described by Watson and Diamond (1947) and Schorr, Braun, and Isaac (1954) were excluded from Table I because of doubt about their final diagnoses in the authors’ reports. Age Incidence.-No age seems to be exempt ; the youngest patient was a premature infant (Doderlein, 1938) and the oldest was a 61-year-old patient (Hosoi and Stewart, 1931). Only 6 cases were over the age of 40 years, but it is of significance to note that 6 cases were below one year of age. Sex Incidence.-Both sexes seem to be equally affected, 20 cases being in males and 17 in females. Incidence of Malignancy.-Ten cases were found to be malignant and 25 were benign. In 2 cases the tumour was reported as arousing suspicions of malignancy. The highest incidence of malignancy was in the third and fourth decades where 7 out of 14 cases were malignant. Location in the Mediastinurn.-The group of vascular tumours is stated to occur in all parts of the mediastinum with equal frequency (Seybold and others, 1949). However, in the cases reviewed in the present study, it was found that the anterior mediastinum was much more frequently affected (26 cases), more noticeably so in benign cases. The tumour not uncommonly reaches such considerable dimensions as to make it difficult to describe it as located in one part or the other. Most masses bulge radiologically to one side of the chest, though occasionally into both pleural cavities. Only in 7 cases was the tumour mainly posteriorly located. Two of the reported tumours originated in the diaphragm muscle.