A 7-year-old boy is brought to the physician by his mother for a 2-month history of a growing lump on his neck. The patient does not report any pain or recent illnesses. Vitals are: temperature 98.6 F, HR 72, RR 16, BP 110/70.

Which of the following is the most likely explanation for this patient’s findings?

A) 1st arch
B) Branchial cleft
C) Foramen cecum
D) 3rd pouch
E) Rathke pouch

A 12-hour boy born 39 weeks’ gestation is evaluated for a palpable suprapubic mass. He has not yet voided but has passed meconium. Pregnancy was complicated by mild oligohydramnios. Which of the following is most likely to be seen in this patient?

A) Abnormality of the urogenital sinus
B) Abnormal retrograde cystourethrogram
C) Opsoclonus-myoclonus syndrome
D) Pyelonephritis
E) Vesicoureteral reflux

A 7-year-old boy is brought to emergency 30 minutes following excruciating left scrotal pain. Physical examination shows a high-riding, horizontally oriented left testis. Which of the following is most likely to be seen in this patient?

A) Blue dot sign
B) Genitofemoral nerve impingement
C) Patent processus vaginalis
D) Positive cremasteric reflex
E) Positive Prehn sign

A 24-year-old woman comes to the physician for a 1-year history of inability to conceive. The uterus demonstrates external fundal indentation. A hysterosalpingogram is shown.

Which of the following is most likely to be seen in this patient?

A) Failure of canalization of the vaginal plate
B) Failure of degeneration of the paramesonephric septum
C) Failure of development of the urogenital sinus
D) Failure of fusion of the mesonephric ducts
E) Failure of fusion of the paramesonephric ducts

A 16-year-old boy is brought to the physician for a 4-month history of progressively worsening changes in his vision. He says he feels slightly “crowded” and has occasionally bumped into pillars in the bus station during busy commutes. Which of the following is the most likely embryologic etiology of this patient’s findings?

A) 2nd pharyngeal arch maturation
B) 3rd and 4th pharyngeal pouch migration
C) Ectoderm of anterior pituitary
D) Endoderm of foramen cecum
E) Roof of primitive oropharynx

A 4-year-old boy is brought to the pediatrician by his parents due to concerns about his appearance and hearing. He was born with a patch of white hair over the forehead and has had bilateral hearing loss since infancy. On physical exam, he has widely spaced inner canthi and irises of two different colors. Growth and development are otherwise normal. Which of the following best explains the pathogenesis of this patient’s condition?

A) Abnormal neural crest cell migration
B) Defective apoptosis of webbed tissue
C) Failure of fusion of the lateral pontine shelves
D) Failure of fusion of the maxillary and medial nasal prominences
E) Persistence of the thyroglossal duct
F) Rathke pouch remnant

A 2-week-old male newborn is evaluated by a specialist pediatrician due to ambiguous genitalia since birth. Physical examination shows a 2-cm phallus a partially fused labioscrotal fold. Karyotype analysis comes back as 46XX. Ultrasound shows no uterus, and serum testosterone is within the normal male newborn range. Which of the following is the most likely explanation for this patient’s findings?

A) 5α-reductase deficiency
B) Androgen insensitivity syndrome
C) Klinefelter syndrome
D) Müllerian agenesis
E) SRY gene translocation

A 2-month-old newborn boy is brought to the emergency department due to persistent bilious vomiting and poor feeding. He was born at term via vaginal delivery without complications and had passed meconium within the first 24 hours. An abdominal x-ray shows dilated loops of small bowel with air-fluid levels. An upper GI series is shown. Which of the following is the most likely explanation for this patient’s presentation?

A neonatal male born at 39 weeks’ gestation is evaluated in ICU. There is a 4/6 holosystolic murmur at the left sternal border. Physical examination shows a cleft lip and palate. Which of the following is most likely to be seen in this patient?

A 6-week-old boy is brought to the pediatrician by his mother for a 2-week history of gradual enlargement of the scrotum. Physical examination shows an enlargement of the left hemiscrotum with positive transillumination. Which of the following is the most likely mechanism of this patient’s presentation and treatment?