Short Phallic Length in a Well-Appearing Newborn

A well-appearing, large-for-gestational-age newborn presented with a short phallic length at birth.Thirty-two-year-old primigravida woman with type 1 diabetes mellitus suboptimally controlled with insulin (hemoglobin A1C 8.2%) and celiac disease.The pregnancy was complicated by severe preeclampsia.Prenatal screening and fetal survey were unremarkable.Delivery via emergency cesarean section due to late fetal decelerations in the setting of severe preeclampsia.Estimated birth gestational age: 37 weeks.The infant cried after the initial steps of resuscitation, and physiological cord clamping was performed. The infant had an Apgar score of 5 and 7 at 1 and 5 minutes, respectively.Vital signs (day 1 after birth): Heart rate = 129 beats/minRespiratory rate = 54 breaths/minOxygen saturation = 98% (in room air)Temperature = 36.8°C (98.2°F)Birth measurements: ○ Weight = 3.624 kg (95th percentile)○ Length = 49 cm (75th percentile)○ Head circumference = 35 cm (94th percentile)Head: Normocephalic, with open, flat fontanelles; symmetric facies; patent nares; intact lip and palate; no neck mass or crepitus.Oral cavity: Pink mucosae, intact palate, normal uvula, normal sucking and rooting reflexes.Lungs: Equal breath sounds bilaterally, no added sounds, no respiratory distress.Cardiovascular: S1 and S2 normal, regular rate and rhythm, no murmurs or gallops.Abdomen: Soft, nontender, not distended, normal bowel sounds heard. No umbilical or inguinal hernia.Genitourinary: Stretched penile length of 2.1 cm (0.83 in) shown in Figure 1; testes bilaterally descended; scrotum well pigmented; normal scrotal rugosity. No hypospadias or chordee.Neurologic: Consolable with appropriate state variability. Feeding well. Normal eye movements without nystagmus. Complete Moro reflex. Normal tone. Appropriate quality and quantity of movements.Skin: Mild icterus (zone 1) was noted late on day 1, with no birthmarks or rashes.Skeletal: Spine appears normal.FIGURE 1.Inconspicuous penis suggesting micropenis vs pseudo-micropenis immediately after birth.Father reportedly had micropenis noted in the newborn period. No other family members had a similar history.The infant passed urine with a strong stream and remained well appearing. The infant’s heelstick glucose levels were normal, and the infant had mild unconjugated hyperbilirubinemia, which remained below treatment threshold.Micropenis ○ Isolated growth hormone deficiency○ Multiple pituitary hormone deficiencies○ Differences of sexual development, such as partial androgen insensitivity syndrome○ IdiopathicBuried penisTrapped penisWebbed penisAt 3 days of age, the stretched penile length increased to 2.8 cm (Figure 2), and the testicular volume measured by Prader’s orchidometer was 1.1 mL, both appropriate for the infant’s age. Thyroid screening was normal, and both hearing and fundus examinations were unremarkable. No significant prepubic fat was observed. On a more detailed examination, the infant’s scrotal skin was noted to extend high onto the ventral surface of the penis, thus forming a web between the penis and scrotum (Figure 3).Primary webbed penis (compound prepenile scrotum type), without phimosis or chordee.A consultation with pediatric surgery was requested, and a Z-plasty was planned for follow-up after 6 months. The infant remained well at a routine newborn follow-up visit at 2 weeks of age.The diagnostic challenge for this infant was to differentiate a true micropenis from a pseudo-micropenis, given the 0.7-cm discrepancy in the stretched penile length measurements at birth and at 72 hours of age. This variation can be attributed to interobserver variability of approximately 0.34 cm, as reported in various studies.1,2 Furthermore, studies indicate that measurements taken within the first 12 hours after birth may yield a 10% shorter result than the actual stretched penile length.3 Although most stretched penile length nomograms are suitable for neonates with appropriate for gestational age growth patterns at full-term gestation, nomograms specific to large- or small-for-gestational-age infants have not been adequately studied. Studies have shown a positive correlation between stretched penile length and gestational age.4,5Interestingly, a positive correlation exists between all anthropometric parameters and stretched penile length, suggesting that identifying micropenis in a large-for-gestational-age infant may be particularly challenging.5,6A webbed penis, or penis palmatus, is a rare congenital condition characterized by a skin fold obscuring the penoscrotal angle.7 The exact cause is unclear, but it may be due to abnormal preputial development, resulting in insufficient ventral skin to cover the penis, leading to overlapping of scrotal tissue.7 This occurs in isolation or alongside hypospadias, chordee, or true micropenis.7 It is classified as primary (congenital: either simple or compound form) or secondary (acquired).8 Diagnosis of a webbed penis is confirmed by lifting the penis to assess the penoscrotal angle.7 Standard surgical options include a V-shaped incision to release the webbed tissue and reapproximation in a “Y” shape for a tension-free closure (V-Y plasty). In more complex cases, a Z-shaped incision releases and rotates tissue around the central part of the Z for improved tension distribution (Z-plasty), often in conjunction with correcting any associated anomalies.9The presence of a well-formed, pigmented scrotum and bilateral descended testes with age-appropriate volume indicated an intact hypothalamic-pituitary-adrenal axis and normal testosterone function, making disorders of sexual differentiation unlikely. Growth hormone deficiency was considered but was less likely because of the absence of hypoglycemia, midline defects, or prolonged jaundice. A buried penis was ruled out because of the lack of significant prepubic fat, whereas a trapped penis due to insufficiency of penile skin as a complication after a procedure, such as circumcision, was ruled out in the absence of any prior penile procedures.SummaryThis case highlights the importance of a detailed assessment of decreased phallic length in a newborn. If examination findings can eliminate micropenis in the differential diagnosis, this can avoid unnecessary investigations and stress for families. This case underscores the need for further studies on the normal stretched penile length in neonates who are small or large for gestational age. The webbed penis, though underreported, can be diagnosed with a detailed examination.American Board Of Pediatrics Neonatal-Perinatal Content SpecificationRecognize disorders of the gonads and secondary sex characteristics.Understand assessment of fetal well-being.