Chronic fibrous mediastinitis and superior vena caval obstruction due to histoplasmosis.

Superior vena caval obstruction has been alleged to be caused by a wide variety of pathological conditions, some rather common and specific while others are relatively rare and indeterminate as to etiology. This troublesome syndrome was first described clinically by William Hunter 200 years ago according to McCord et al.1 In their excellent review, Mclntire and Sykes2 cite that Fischer’s series of 252 cases, reported prior to 1904, was comparable as to symptomatology and prognosis to the 250 cases appearing in the literature from 1904-1946. Superior vena caval obstruction related to chronic fibrous mediastinitis was uniformly felt to be due to tuberculosis or syphilis until about 35 years ago. Surgical or autopsy verified cases of idiopathic fibrous mediastinitis have been reported with increasing frequency since that time.2’5 Improvement in diagnostic technic of syphilis and tuberculosis were felt responsible for this change. The possibility of considerable diagnostic error was noted, particularly in earlier cases.2 In the verified cases of chronic fibrous mediastinitis reported, a granulomatous lymph node has frequently been associated with the process and occasionally has contained calcium.24 10, 12. 13. 15, Other clinical cases have also shown this relationship.1 17i9 A diagnosis of tuberculosis has occasionally been made on the basis of these findings, however, when a specific statement has been made about microscopic findings of caseous granulomas, acid fast bacilli have not been demonstrated.4’ 5, 13 The unreliability of tissue etiologic diagnosis without demonstration of organisms has been well documented by Puckett.2#{176} In 1925 Knox3 noted that other agents which produce granulomata, such as the mycoses, might be the cause of fibrous mediastinitis. As late as 1956 Gillespi&suggested that upper an lower respiratory infections, bronchopneumonia, influenza, tularemia, trauma, rheumatic fever, and a tendency to form keloids might be implicated in chronic fibrous mediastinitis. Gillespie16 reported the case of a seven-year-old girl from a rural community of southern Illinois who developed superior vena caval obstruction in 1954, three and one half years after “virus-pneumonia.” Chest roentgenogram showed multiple areas of fibrosis and calcification in both lung fields, rather marked infiltration or fibrosis in the upper two thirds of the right lung and pleural thickening along the right upper mediastinum. Blood serum complement fixation for histoplasmosis was 1 :64 (yeast phase antigen). The histoplasmin skin test was strongly positive, but the old