Plasma growth hormone in patients with chromosomal anomalies.

307 skull and a short vertebral column in the middle, which was connected at its lower end to a pelvic girdle. The lower limb skeletons, which were complete, arose from the pelvic girdle. Histologically, the specialized tissues found were skin with hair follicles and sweat glands. Sebaceous glands were conspicuous by their absence. Also cartilage, bone marrow, adipose tissue, fibrous tissue, muscle tissue, nerves, and blood vessels were found. At the base of the sac there was tissue resembling primitive chorionic villi (Fig. 4). Discussion A fetus in fetu is a parasitic twin within its fellow. In contrast, a teratoma is a true neoplasm which arises from the embryonic pleuroperitoneal cells with benign or malignant properties. The most likely explanation is that it is a monozygotic twin of its bearer. The criterion for diagnosing fetus in fetu was adopted by Willis (1935). He emphasized the presence of an axial skeleton with a vertebral axis with an appropriate arrangement of other limbs and organs, with respect to the axis. This would distinguish fetus in fetu from a teratoma. Most of the described cases have been intra-abdominal. Of these, except for 2 cases, all have arisen from the retroperitoneal tissues of the upper abdomen. One case described by Lee (1965) arose from the pelvis. Another reported by Numanoglu, Gokdemir, and Oztop (1970) arose from the mesentery of the ileum. Our case arose from the retroperitoneal tissue of the upper abdomen. An unusual feature about our case was the presence of well-differentiated limbs with nails but with absence of well-differentiated internal organs. Possibly it consisted of two fused fetuses as suggested by the presence of multiple limbs. An interesting feature was the presence of tissue resembling chorionic villi, with a central core containing blood vessels, attached to the base of the sac. While most cases have been in infants, our patient was 1 year 8 months old at time of diagnosis and had had symptoms for only 2 months. Summary A case offetus in fetu is described. It was found enclosed in a sac arising from the retroperitoneal tissues of the upper abdomen in a 20-month-old girl. Dissection of the specimen revealed a vertebral spine with a pelvis and well-differentiated limbs complete with nails. Previously reported cases are reviewed. Since the advent of the radioimmunoassay method for measurement of human growth hormone in peripheral blood, several studies have been performed on individuals with …