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

We found a microvascular endothelial abnormality in a biopsy specimen from the gastrocnemius muscle of a patient with gastric cancer, who had severe m yalgia and angialgia in the calf region with the symptoms of thrombophlebit is. There were no definite findings of inflammatory myopathy in histochemic al and immunohistochemical studies. Electron microscopic examination reveal ed the accumulation of abnormal mitochondria in the subsarcolemmal area, an d a fair number of degenerating capillaries. Immunohistochemical analysis o f procoagulant or anticoagulant factors revealed marked reduction of thromb omodulin (TM) expression on small vessels and capillaries. Although a reduc tion of TM on small vessels has been observed around perifascicular atrophi c fibers in patients with dermatomyositis, histochemical findings of the pr esent patient showed no perifascicular atrophy or severely degenerating fib ers. These pathological findings in the patient may be related to a maligna nt neoplasm and may be one of the causes of disseminated intravascular coag ulation (DIC), which is the main complication of malignant neoplasms. Furth er studies are necessary to determine whether the reduction of TM on the sm all vessels and capillaries in skeletal muscle is a predictor of some sever e condition such as DIC or a rare pathological finding in some special cond ition such as scirrhous carcinoma with thrombophlebitis.