Anatomical Aspects of the Insufficiently Developed Genital Tubercle
Micropenis can be related to failed central hormonal stimulation such has gonadotrophic stimulation or GH stimulation. It can also be the consequence of a poor tissue response (5-α reductase deficiency; partial androgen insensitivity) [22]. Hypospadias is classically represented by the association of a ventrally bent GT, a ventral opening of the urethra at any place between the glans and the perineum, and abnormal distribution of the penile skin. It is the result of a development halt of the tissues forming the ventral aspect of the penis. As a result, the corpus spongiosum, which normally surrounds the urethra, divides creating a ventral triangular defect whose summit is the division of the spongiosum; the lateral sides are the atretic pillars of spongiosum reaching the glans wings, and the open glans forms its base. All of the tissue in this triangle is poorly developed, leading to the ventral curvature of the penis and the poorly formed urethra. Most hypospadias classifications are wrongly based on only the position of the urethral meatus. The GT anomaly is far more complex and its severity must include the size of the GT, the glans, the length of the defective urethra, the quality of the tissues forming the urethral plate, and, moreover, the level of division of the corpus spongiosum. Accurate identification of GT development can only be established in the operating room, once the GT has been fully degloved. One can then distinguish hypospadias with a proximal division of the corpus spongiosum, which are associated with a ventral curvature, from those with a distal division of the corpus spongiosum, which have little or no curvature.
A micropenis is a fully formed GT with a size under 25 mm in length (or under 2-2.5 SD) during the first year of life. It must be distinguished from the buried GT which has a normal size but a significant skin shaft shortage, and from the webbed penis which is the abnormal anchorage of the scrotal skin onto the ventral aspect of the penis [23].
Most deficient GT are diagnosed at birth or in the first few months of life. It is possible to identify some of the most severe anomalies during the prenatal period. Most GT anomalies are straightforward. Conversely, severely hypovirilized GT, in association with other genital anomalies (undescended testes, large mullerian cavity) and discrepancy between the genital aspect and the karyotype, may raise difficult discussions regarding the choice of gender (gender assignment) [24–26]. These rare situations should involve an experienced multidisciplinary team including endocrinologists, geneticists, molecular biologists, psychologists, pediatric urologists, grown-up patients, and, of course, the parents. It is amazing that, at the dawn of the third millennium, one still does not know what makes a boy a boy and a girl a girl. Observational medicine of multiple, and individual, clinical cases is the only tool we have to build the foundations of an approach to the most complex cases. We have learned from these observations that the status of chromosomes, hormones, gonads, the phallus, the vagina, etc., are not sufficient to define a boy or a girl [27]. National and international meetings and think tanks such as the Chicago Consensus Meeting (2005) and EuroDSD have encouraged the exchange of ideas, data bases, research programs, and publications [28].
Sexual Identities
Understanding of and decision making for a child in the neonatal period with severely abnormal genitalia is an extraordinary challenge. It is quite paradoxical to opt for a gender without consulting the patient himself or herself. This process has been highly criticized by some patients and patient advocacy associations and remains quite controversial. To understand the complexity of these situations, one could distinguish three different identities. Individual sex identity, which is what the individual thinks he or she is, is quite a subtle spectrum and will be shaped by growth and external and internal influences. Behavioral identity, which is the individual’s erotic inclination, will also form with time. Both of these identities are invisible in the neonatal period. The last identity, i.e. social identity, (or gender) is how society looks at the individual and recognizes the individual as male or female. Social/gender identity is far more rigid, and less subtle, than the others. It is the way the social mirror reflects the individual’s image, i.e. the way to make the individual visible. It is the only tangible identity at birth.
Decision Tools
A newborn with undefined sex is moral torture for parents who cannot present a gendered child to the family. It is therefore a matter of relative urgency to choose a gender which will render this child visible to society. Four factors influence the choice of gender: (1) internal sex, represented by the child’s genetic, gonadal, and hormonal profiles; (2) external sex, which is the appearance of the genitalia, and more specifically the size of the GT and the possible presence of a retrourethral müllerian cavity; (3) functional sex, which comprises the potential future fertility and the capacity of having intercourse as a male or a female, and (4) social sex, which refers to the cultural medium where the child will grow. The mother’s deep feelings are of utmost importance in this decision-making process [29].
Hormonal Treatments
Steroid treatments are mainly based on androgen stimulation to enlarge the penis. There is no consensual protocol on if, when, and how to stimulate GT growth. There are three main possibilities: systemic testosterone (testosterone enanthate), topical DHT, and HCG (human or recombinant). When the GT is under 25 mm in length and 15 mm in width during the first year of life, androgen stimulation is commonly used. Some adverse effects, such as bone growth, should be monitored. It is also acknowledged that androgen treatments might be deleterious to the healing process after reconstructive surgery [30]. A 3-to 6-month gap between stimulation and surgery is recommended. Androgens mainly act on the growth of the GT dorsum and the ventral segment situated proximal to the division of the corpus spongiosum. Tissues located beyond the division of the corpus spongiosum are likely less androgen sensitive. These dysplastic tissues solely used in hypospadias reconstruction may not grow as well as the rest of the penis. This would explain the late urethral inadequacy with some techniques (Duplay, tubularized incised plate). Some surgeons favor the use of dorsal tissues for urethroplasties (onlay urethroplasty) which have a normal response to androgen stimulation.
Masculinization Surgery
DSD surgery should be done by DSD surgeons, i.e. surgeons familiar with genital reconstruction in children. Hypospadias reconstruction is commonly performed between 6 months and 2 years of age and includes three main steps. The first step is full dissection of the GT to expose the level of division of the corpus spongiosum which is the proximal landmark of the GT anomaly. It is then possible to evaluate the quality of the tissues available and choose the most appropriate technique for urethroplasty. In the second step, the choice of urethroplasty is dependent upon the length of the urethra to reconstruct, the quality of the urethral plate, the size of the glans, and the availability of dorsal tissues. The third step consists of refashioning the ventral aspect of the GT by redistributing the tissues around the penis, with or without conservation of the foreskin. There is no universal technique for hypospadias repair and no gold standard technique. The outcome is dependent upon many factors, the most important of which is the experience of the surgical team and the quality of postoperative care.
Phalloplasty is even more challenging and has been imported from adult urological surgeons experienced with transsexual surgery. Experience and follow-up in children is extremely short and these procedures should be confined to one or two places on each continent. Main indications are represented by aphallia, a very small GT in males, or a damaged penis after exstrophy