Delayed Puberty in Male

Delay in onset of secondary sexual development after 13.5 years in boys → Serum gonadotropins

• Elevated → Karyotype
• Low → Growth pattern

Elevated gonadotropins — Karyotype

• 47,XXY → Klinefelter syndrome (onset of puberty often normal but poor progression follows)
• Normal 46,XY → Primary testicular failure

Low gonadotropins — Growth pattern

• Consistently short for chronologic age but appropriate for bone age → Bone age delayed → Constitutional delay in growth and puberty
• Late-onset growth failure especially with concurrent diabetes insipidus → MRI → Mass → CNS tumor
• Normal without growth spurt → Sense of smell

Sense of smell pathway

• Anosmia or hyposmia → MRI → Absence of olfactory bulb and/or sulcus → Kallmann syndrome (cryptorchidism and/or microphallus make this more likely)
• Normal sense of smell → Normal MRI → Isolated gonadotropin deficiency (cryptorchidism and/or microphallus make this more likely)