A 67-year-old man was seen at the hospital because of a painless tumor in the left antebrachial region about 4 months following an operation for advanced gastric cancer. On palpation, a movable elastic hard tumor was palpated in the left antebrachial region. Ultrasonographic study of the legion revealed a relatively well-demarcated and hypoechoic mass in the muscle. The mass was removed with a diagnosis of tumor of the left antebrachial region. The tumor was present in the carpal extensor muscle. The removed tumor was 2.9×1.7×1.5cm in size and was covered with thin capsule. The cut surface was milk white in color. Histopathologically, poorly to moderately differentiated adenocarcinoma in the muscular tissue was demonstrated. Metastasis of the gastric cancer to the muscular layer was diagnosed. After the removal, an exploration of the whole body including the lung and liver revealed no other recognizable metastatic foci. About 2 months later, however, recurrence in the musculature of the left forearm as well as a similar tumor in the right chest (in the right anterior serratus muscle) was confirmed. These tumors were removed again. Histopathologically, recurrence of muscular metastasis was diagnosed.
In a review of 17 cases of muscular metastasis of gastric cancer including this case in the Japanese literature, the muscular metastasis commonly occurs in the lower extremities and has no certain propensity for histologic type.
Nihon Rinsho Geka Gakkai Zasshi (Journal of Japan Surgical Association)