Nejm 1986;314:510

2-3% of term babies, decreases to 0.7% at age 1 yr without treatment, then prevalence is flat thereafter

Si: Unilateral in 75%, bilateral in 25%; most have associated inguinal hernia

Sterility, questionably prevented by early operation and may even be the same as normals

Cancer in affected and contralateral testicles, increased 20-40 ×; higher with higher inguinal canal location even postoperation; cellular changes w/i 6-12 mo of nondescent

r/o retractile (normal) nonscrotal testicle that can be manipulated to bottom of scrotum; virilized female prepubertally w serum Müllerian inhibiting substance level, which is present in boys but not girls w 92/98% sens/specif (Nejm 1997;336:1480)

Rx:

Surgery by age 1 yr; does not decrease CA risk (Cancer 1982;49:1023) or survival (Peds 1996;97:590) but improves fertility and facilitates self-exam. Swedish study finds surgery before puberty (13 yr) still has 2.25% relative risk incr but after 13, risk incr × 5+%

Hormonal rx with HCG or GnRH not much help (Nejm 1986;314:466, 510)

Educate teenagers to do careful testicular self-exam

Figure 13.2 Interpretation of the Assay of Serum Müllerian Inhibiting Substance in the Evaluation of Boys with Bilateral Undescended Testes or Children with Intersexual Disorders

Boys with Bilateral Undescended Testes (Normal Phallus)

Children with intersexual Disorders (Ambiguous Genitalia)

Reproduced with permission from Lee MM, et al. Measurements of serum mullerian inhibiting substance in the evaluation of children with nonpalpable gonads. New Eng J Med 1997:336:1480. Copyright 1997 Mass. Medical Society, all rights reserved.