Agenesis of the penis: Patterns of associated malformations

Agenesis of the penis is a rare malformation that occurs in otherwise norma l males or together with other anomalies. In this article, we document unus ual patterns of malformations in four such infants and analyze the nature a nd incidence of defects in 57 cases by clinical evaluation and numerical cl assification techniques. Although patients with this condition previously h ave been divided into groups based on the position of the urethral meatus i n relation to the anus (presphincteric, postsphincteric, urethral atresia), our analyses suggest that most cases can be classified into either a sever e form (16%) with renal aplasia or dysplasia and other caudal anomalies or a second group (72%) with low mortality and fewer additional malformations. The remaining cases in our group represented unique patterns stemming from a variety of causes, including etretinate embryopathy and the human homolo gue of the disorganization mutation. Agenesis of the penis occurs as a cons equence of single gene disorders, teratogenic effects, or malformation sequ ences and associations and in unrecognized patterns of anomalies. It thus s hould be considered a developmental field defect, Its concurrence with scro tal hypoplasia, absent raphe, and anal anomalies implies a major disturbanc e of the caudal mesoderm, In such cases, severe renal defects are usually s een, and the prognosis is poor. When the patient has a patent urethra and n ormal scrotum, raphe, and testes, however, penile agenesis may be a localiz ed malformation of the genital tubercle potentially related to penoscrotal transposition, a phylogenetic anomaly that is the normal genital arrangemen t in male marsupials, rabbits, and certain other mammals. Infants with isol ated penile agenesis have generally done well. In the past, many were not t reated; however, current recommendations are to use appropriate surgical an d endocrine techniques to reassign female gender and enhance sexual and psy chosocial functioning, though this approach is the subject of controversy. (C) 1999 Wiley-Liss, Inc.