A 9-month-old girl is brought to the clinic for a well-child visit. She was born precipitously at 35 weeks gestation due to preterm labor to a 22-year-old primigravida who did not receive prenatal care. The patient's neonatal course was notable for a 1-week hospital stay due to difficulty feeding. She was hospitalized for bronchiolitis at age 3 months for 4 days. The patient can crawl but has not begun cruising. She has been babbling and repeating "mama." Height, weight, and head circumference track along the 25th percentile. She is alert and smiling at the examiner and her mother. Ophthalmoscopic examination reveals a white reflex in the left eye and a red reflex in the right. Extraocular movements are intact, and the pupils are equal and reactive to light. The corneal light reflex is symmetric. The remainder of the examination is normal. Which of the following is the most likely cause of this patient's physical examination findings?

Question

A 9-month-old girl is brought to the clinic for a well-child visit.  She was born precipitously at 35 weeks gestation due to preterm labor to a 22-year-old primigravida who did not receive prenatal care.  The patient's neonatal course was notable for a 1-week hospital stay due to difficulty feeding.  She was hospitalized for bronchiolitis at age 3 months for 4 days.  The patient can crawl but has not begun cruising.  She has been babbling and repeating "mama."  Height, weight, and head circumference track along the 25th percentile.  She is alert and smiling at the examiner and her mother.  Ophthalmoscopic examination reveals a white reflex in the left eye and a red reflex in the right.  Extraocular movements are intact, and the pupils are equal and reactive to light.  The corneal light reflex is symmetric.  The remainder of the examination is normal.  Which of the following is the most likely cause of this patient's physical examination findings?

Quizplus · Accepted Answer

11ec25c8_d703_a587_bc81_1f4367280459_MD0003_00 This patient has leukocoria (white pupillary reflex) concerning for retinoblastoma, the most common intraocular tumor of childhood, which occurs due to inactivation of the tumor suppressor gene RB1. Sporadic retinoblastoma often presents as unilateral disease, whereas inheritable retinoblastoma is more commonly bilateral. Retinoblastoma is typically diagnosed in children age <2 and should therefore be suspected in any infant or young child with an absent red reflex. Other presenting features include strabismus, nystagmus, vision impairment, and ocular inflammation. Immediate ophthalmologic referral is required for treatment to avoid metastasis to the contralateral eye and the brain. Diagnosis is confirmed with MRI of the brain and orbits. Biopsy is not performed due to risk of tumor seeding. MRI of the brain and orbits (Choices A and B) Cytomegalovirus and rubella are congenital infections contracted in utero that can cause leukocoria due to cataracts (lens opacification). However, bilateral white pupillary reflexes and abnormalities such as hearing loss and microcephaly would be expected with these conditions. (Choice C) Retinitis pigmentosa is a genetic disorder characterized by progressive retinal degeneration. Typical presentation includes night blindness, decreased visual acuity, and visual field loss. Cataracts can develop but are very rare in infancy. (Choice E) Severe retinopathy of prematurity with associated retinal detachment can cause leukocoria, but it is unlikely in this patient because the condition typically affects infants born at <30 weeks gestation. Educational objective: Leukocoria, or white pupillary reflex, in an infant or young child should prompt immediate referral to an ophthalmologist to evaluate for retinoblastoma. Strabismus and nystagmus are other red flags. References: Retinoblastoma. (http://www.ncbi.nlm.nih.gov/pubmed/22414599) Differentials and approach to leukocoria. (http://www.ncbi.nlm.nih.gov/pubmed/23589950)

A 9-Month-Old Girl Is Brought to the Clinic for a Well-Child