Primary Lymphosarcoma of the Lung.

Pulmonary involvement in disseminated lymphosarcoma is comparatively common. Vieta and Craver (1941) found an incidence of nearly 25% by radiographic assessment in a series of 239 patients with lymphosarcoma* and a similar proportion of a smaller number coming to necropsy. This figure agrees closely with the post-mortem incidence reported by Robbins (1953) in an even larger series. More recently, Rosenberg, Diamond, Jaslowitz, and Craver (1961) found approximately 40% with lung involvement in a necropsy series of 277 cases of lymphosarcoma. At St. Bartholomew's Hospital, 86 patients with histologically proven lymphosarcomat have been admitted over the last ten years. In 12 of these patients there was radiographic evidence of pulmonary involvement. Primary lymphosarcoma of the lung is, on the other hand, a rare disease. Sugarbaker and Craver (1940) found only one instance of a primary lung tumour in a series of 196 cases of histologically proven lymphosarcoma. Its importance, however, far outweighs the incidence, for it is a slowly growing tumour which tends to remain localized for a long time, spreading by direct extension into neighbouring structures, rather than metastasizing by the blood or lymph streams. The tumour is therefore often amenable to complete surgical excision. The diagnosis of this disease is difficult, for symptoms are usually mild or absent and physical examination will at the most reveal signs of consolidation. The radiographic picture is nonspecific and in most instances has given rise to a suspicion of bronchial carcinoma. Baron and Whitehouse (1961) have, however, emphasized the patency of the bronchi in pulmonary lymphosarcoma and have drawn attention to radiographic appearances which they describe as an 'air bronchogram.' Bronchoscopy has seldom proved helpful in diagnosis in spite of the frequent