A 6-year-old boy is brought to the office for a routine health maintenance examination. Several "dark spots" on his trunk have been increasing in number and now appear to be spreading. The skin lesions are not painful or pruritic. The patient has no chronic medical conditions and takes no medications. He has reached all developmental milestones and is in the first grade. Maternal family history is noncontributory. The parents are divorced and paternal history is unknown. Blood pressure is 98/64 mm Hg and pulse is 100/min. The patient is at the 25th and 50th percentile for height and weight, respectively. Examination shows an alert, active boy. Pupils are equal and reactive bilaterally. Cranial nerves II-XII are intact. Cardiac examination reveals a regular rate and rhythm; no murmurs are auscultated. The abdomen is soft and has no palpable masses. Scattered 1×2 cm, hyperpigmented macules are seen over the trunk, left arm, and right thigh, as shown in the exhibit, and numerous 2×3 mm, hyperpigmented macules are seen in the bilateral inguinal creases. The patellar and Achilles deep tendon reflexes are 2/4 bilaterally. Muscle bulk and tone are normal in all extremities. Which of the following is the best next step in management of this patient?

Question

A 6-year-old boy is brought to the office for a routine health maintenance examination.  Several "dark spots" on his trunk have been increasing in number and now appear to be spreading.  The skin lesions are not painful or pruritic.  The patient has no chronic medical conditions and takes no medications.  He has reached all developmental milestones and is in the first grade.  Maternal family history is noncontributory.  The parents are divorced and paternal history is unknown.  Blood pressure is 98/64 mm Hg and pulse is 100/min.  The patient is at the 25th and 50th percentile for height and weight, respectively.  Examination shows an alert, active boy.  Pupils are equal and reactive bilaterally.  Cranial nerves II-XII are intact.  Cardiac examination reveals a regular rate and rhythm; no murmurs are auscultated.  The abdomen is soft and has no palpable masses.  Scattered 1×2 cm, hyperpigmented macules are seen over the trunk, left arm, and right thigh, as shown in the exhibit, and numerous 2×3 mm, hyperpigmented macules are seen in the bilateral inguinal creases.  The patellar and Achilles deep tendon reflexes are 2/4 bilaterally.  Muscle bulk and tone are normal in all extremities.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

Explanation: 11ec2b69_bf55_bbe7_8f63_6356c9f0d059_MD0005_00 Neurofibromatosis type I (NFI) is an autosomal dominant disorder due to a mutation in the NF1 tumor suppressor gene on chromosome 17q11.2. Café-au-lait macules (CALMs) are a hallmark feature. Although a few CALMs are common in the general population, patients with NFI have numerous, widespread CALMs that typically increase in number during childhood. In addition, freckling in the inguinal and axillary skin folds, as seen in this patient, is highly concerning for NFI. Other common features include neurofibromas, which are benign peripheral nerve sheath tumors in the skin, and Lisch nodules, which are iris hamartomas that do not affect vision. neurofibromas Once the diagnosis of NFI is suspected, ophthalmologic evaluation for optic pathway gliomas is indicated. Bilateral optic pathway gliomas are virtually pathognomonic for NFI but may be asymptomatic initially. Early detection is critical due to risk of progressive vision loss. Visual acuity, confrontation visual field testing, color vision testing, and extraocular motility must be assessed. If the eye examination is abnormal, MRI of the brain and orbits may be performed to determine tumor size and extent of intracranial extension. (Choice A) Patients with neurofibromatosis type II (NFII) require audiologic evaluation for sensorineural hearing loss due to bilateral vestibular schwannomas, which are not as common in NFI. CALMs are not a classic feature of NFII. (Choice B) Biopsy of CALMs is not required as they do not have a malignant potential, in contrast to plexiform neurofibromas, which can also occur in NFI but are not present in this patient. (Choice D) Reassurance and observation would be indicated if the patient had only a few isolated CALMs. (Choice E) Serum growth hormone is often elevated in patients with McCune-Albright syndrome, which classically presents with CALMs with irregular borders as well as fibrous dysplasia and precocious puberty. This patient has CALMs with smooth borders, consistent with NFI. Educational objective: Neurofibromatosis type I is an autosomal dominant disorder characterized by multiple café-au-lait macules plus axillary or inguinal freckling. Ophthalmologic evaluation is required to screen for optic pathway gliomas. References: The use of magnetic resonance imaging screening for optic pathway gliomas in children with neurofibromatosis type 1. (http://www.ncbi.nlm.nih.gov/pubmed/26233602) Clinical and genetic aspects of neurofibromatosis 1. (http://www.ncbi.nlm.nih.gov/pubmed/20027112)

A 6-Year-Old Boy Is Brought to the Office for a Routine