Penoscrotal Transposition
A 6-month-old boy was brought into the pediatric clinic for a visit after hospital discharge. Because of preeclampsia and breech presentation, he had been born prematurely via cesarean delivery at 24 weeks of gestation to a 30-year-old primiparous mother. He was admitted to the neonatal intensive care unit (NICU) for observation and management of his respiratory condition. Due to significant respiratory distress and his worsening condition, he was shifted to a level 3 NICU, where he was treated for persistent pulmonary hypertension.
The infant’s neonatal complications included secondary pulmonary hypertension, inguinal hernia, grade 1 intraventricular hemorrhage, stage 1 retinopathy of prematurity, severe respiratory distress and tracheostomy tube placement, and gastrostomy tube placement due to severe gastroesophageal reflux.
He had been born to nonconsanguineous parents. The mother denied any drug use or teratogenic substance use during pregnancy.
On the day of examination in the clinic, the infant was alert, active, and in no distress. The tracheostomy tube was in place and intact, with no profuse secretions, and he was stable on a flow rate of 0.5 L/min of oxygen. His respiratory condition was stable, with tracheostomy settings at baseline (positive end-expiratory pressure, 8 cm H2O; continuous positive airway pressure, 20 cm H2O; respiratory rate, 20 breaths/min; oxygen flow rate, 0.75 L/min).
Cardiac examination findings were normal, with a regular rate and rhythm and no murmurs appreciated. His abdomen was slightly distended, and he had a gastrostomy tube in place with no leakage or surrounding skin erythema. His skin had no rashes, and his extremities were normal.
Prominent postsurgical scars from bilateral inguinal hernia repair were visible in the groin area. Genital examination findings were unusual: The scrotum was abnormally placed and bifid along the scrotal raphe, with the penis submerged between the two halves of the scrotum. Both testes could be palpated within the scrotum and were completely descended. He also had hypospadias with chordee.
The boy’s mother mentioned that he had been tested and had been given a diagnosis of ambiguous genitalia.
Karyotyping was performed and showed 46,XY, and he received a diagnosis of complete penoscrotal transposition (PST) with hypospadias and chordee. Echocardiography was positive for patent ductus arteriosus, which was medically closed. Renal ultrasonography findings were normal. Other than hypospadias, he had no other associated genitourinary abnormalities.
Discussion
PST is an extremely rare congenital malformation characterized by malposition of the penis with respect to the scrotum. The scrotum is placed anterior and superior to the penis. PST results from abnormal genital tubercle development at approximately the sixth week of gestation. The condition is associated with delay in the midline fusion of the urethral folds. PST commonly presents in 2 forms: complete transposition with either a normal scrotum or a bifid scrotum, with the penis completely ectopic or with the scrotum covering the penis, which emerges from the perineum; and incomplete transposition, where the scrotum is parapenile. Fewer than 20 cases of an extreme degree of PST with a normal scrotum have been reported in the literature.16
This rare congenital condition has been associated with genital and nongenital anomalies. Associated genital malformations include simple shawl scrotum (doughnut scrotum), hypospadias, double urethra, meatal stenosis, and penile torsion.
Renal abnormalities range from hydronephrosis to severe dysplastic kidney leading to renal failure and even death. Gastrointestinal malformations can range from remnant vitellointestinal duct to large bowel obstruction.19 Cases with severe cardiovascular abnormalities (eg, severe aortic stenosis) and pulmonary abnormalities (eg, pulmonary hypoplasia, pulmonary hypertension) have been reported. Other nongenital manifestations include craniofacial, musculoskeletal, neuropsychiatric, and endocrine complications.3-19
Although the occurrence is sporadic, cases associated with chromosomal abnormalities have been reported.10 It is more common in prepubertal boys, but cases have been reported as late as the early 50s and as early as the prenatal period.
The differential diagnosis of PST includes pseudohermaphroditism, ambiguous genitalia, penoscrotal hypospadias, micropenis, intrauterine penile amputation, and penile agenesis with a midline skin tag anterior to the anus.
Management of all forms of PST comprises initial treatment of associated urinary and other abnormalities, followed by surgical correction of the PST. Different surgical procedures have been described for correction of various types of PST. In more complex cases of PS, surgery is technically challenging. It is usually performed during early childhood. The size of the phallus and its potential to develop at puberty into a sexually satisfactory penis are of paramount importance when surgery is planned. In order to assess this, a surgeon must carefully palpate the corporal bodies to determine their bulk and sometimes perform a testosterone test to demonstrate erections. Extreme PST with severe hypospadias and chordee is difficult to differentiate from penile agenesis with a midline skin tag anterior to the anus (with penile atrophic body buried in the perineum).
In cases that are not severely compromised by renal or other associated anomalies, modern corrective techniques usually can provide normal urinary and sexual function. Psychological support subsequently may be required, depending on the completeness of the repair.
Survival among reported cases of PST varies depending on the associated abnormalities. In uncomplicated cases, survival into adulthood has been reported, and in some cases with fertility intact, but paternity in cases of PST has not yet been studied. In complicated cases, the mortality rate is significantly high due to associated visceral organ anomalies.
So far, 4 reported cases of extreme premature boys with true PST have been reported in the literature, with the longest survival being 2 months as a result of associated severe anomalies. Our case is the fifth case in this category of the prematurity with true PST, but so far it is the first case with survival beyond infancy.
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