Microvascular endothelial abnormality in skeletal muscle from a patient with gastric cancer without dermatomyositis

Abstract

We found a microvascular endothelial abnormality in a biopsy specimen from the gastrocnemius muscle of a patient with gastric cancer, who had severe myalgia and angialgia in the calf region with the symptoms of thrombophlebitis. There were no definite findings of inflammatory myopathy in histochemical and immunohistochemical studies. Electron microscopic examination revealed the accumulation of abnormal mitochondria in the subsarcolemmal area, and a fair number of degenerating capillaries. Immunohistochemical analysis of procoagulant or anticoagulant factors revealed marked reduction of thrombomodulin (TM) expression on small vessels and capillaries. Although a reduction of TM on small vessels has been observed around perifascicular atrophic fibers in patients with dermatomyositis, histochemical findings of the present patient showed no perifascicular atrophy or severely degenerating fibers. These pathological findings in the patient may be related to a malignant neoplasm and may be one of the causes of disseminated intravascular coagulation (DIC), which is the main complication of malignant neoplasms. Further studies are necessary to determine whether the reduction of TM on the small vessels and capillaries in skeletal muscle is a predictor of some severe condition such as DIC or a rare pathological finding in some special condition such as scirrhous carcinoma with thrombophlebitis.