Disorders of Sexual Development from the Pathologist’s Perspective

Abstract

The diagnosis of patients with disorders of sexual development (DSD) is complex. The assignment of a male or female gender, which often does not depend on its karyotype, is just the beginning of a long process that only ends happily when the phenotypic sex is coincident with the psychological sex. In the middle there is a teamwork of, among others, geneticists, endocrinologists, surgeons, and pathologists. In this and in the following three chapters, it is our intention to reclaim the central role that requires the knowledge of the histology of the gonads. For this purpose we have used a histological classification of DSD, based on the degree of differentiation of the gonad into either testis or ovary. We have considered the following types of gonads: undifferentiated gonadal tissue, classical streak gonad, hypoplastic ovary, streak gonad with epithelial cord-like structures, dysgenetic testis, streak testis, ovotestis, and structurally normal testicles. From the histological viewpoint, this chapter discusses the different clinical patterns and the most common karyotype in each of the entities associated with the presence of the classical streak gonad (Turner’s syndrome and 46,XX pure gonadal dysgenesis).