Such tumors are often microadenomas, and plasma prolactin assays are more sensitive than radiologic examination in detecting them. Turner's syndrome and its variants are the ones best understood. In the full-blown disorder, primary amenorrhea and genital immaturity are accompanied by short stature and various congenital anomalies. Patients are chromatin negative, have a 45,X karyotype, and have easily recognizable physical features. Much more troublesome are mosaic chromosome disorders, in which body cells show a mixture of karyotypes.
Recognition is particularly difficult when some cells are normal.
A patient with a mosaic of 45,X and 46,XX cells, for example, may be almost normal in height, have few anomalies, and have either primary or secondary amenorrhea. In one study, conception occurred in 24 patients with variants of Turner's syndrome, but many of the pregnancies were abnormal. Clearly, a high index of suspicion is needed, and the diagnosis is often suggested by partial deficiency in height, by the presence of a few of the anomalies of Turner's syndrome, or by other findings. Menses are prevented by excessive androgens, which override estrogen production and effects. Patients are normal in height and do not have congenital defects but usually have hirsutism and increased muscularity.