Histopathological study of mixed connective tissue disease from 32 autopsy cases in Japan

Abstract

In order to identify the histological specificity of newly defined connective tissue disease, we examined 32 autopsy cases of mixed connective tissue disease (MCTD) which fulfilled the disease criteria proposed by the Japanese MCTD Committee. The age of the 32 cases ranged from 19 to 79 with an average age of 43 years. The male: female ratio was 3∶29. The duration of illness was 7.9 years on average. These tendencies were not so specific compared with other connective tissue diseases. In reference to the cause of death, pulmonary hypertension associated with severe pulmonary arterial lesions such as plexogenic arteriopathy and intimal thickening was found in 16 cases, which was 34% of all total autopsy cases. Totally pulmonary diseases including pulmonary hypertension, pulmonary fibrosis and interstitial pneumonitis amounted to half of all fatal cases. Following pulmonary disease, esophageal fibrosis, sialoadenitis and cardiac involvement succeeded. Although clinical signs such as dysphagia or hypomotility did not necessarily present before death, the frequency and severity of histological changes of the esophagus cannot be ignored. Accompanied with sicca syndrome, the salivary gland showed variable stages of inflammatory changes from slight lymphocytic infiltration in the periductal region to severe parenchymatous atrophy with severe fibrosis. Autopsy cases of MCTD disclosed myocardial damage in not a few cases, which were often accompanied with fibrosis, and these features were very similar to the those of esophageal lesions. On the other hand, involvement of the kidney, skin and muscle was very slight in MCTD compared with those of systemic lupus erythematosus, progressive systemic sclerosis and polymyositis/dermatomyositis. The kidney lesion was characterized by membranous glomerulonephritis. Skin continued to be scleroedematous in spite of long term illness. Muscle showed slight lymphocytic infiltration around small vessels and interstitium. In addition to serological and clinical features, histopathological study revealed specific features of MCTD different from other connective tissue diseases. In treatment and follow-up of the patients of MCTD, special care should be paid to the conditions of this disease which reflect the histological changes as presented here.