Review Question - QID 108867

The most likely diagnosis in this vignette is tuberous sclerosis. Children with tuberous sclerosis are at an increased risk of developing cortical hamartomas, retinal hamartomas, cardiac rhabdomyomas, and renal angiomyolipomas.

In this infant with a history of recent infantile spasm and skin findings of hypopigmented macules, a neurocutaneous syndrome should be suspected. Cutaneous manifestations of tuberous sclerosis include hypopigmented macules (ash leaf spots) that are best visualized under ultraviolet light as seen in this case, angiofibromas (adenoma sebaceum), and patches of leathery thickening (shagreen patches). Tuberous sclerosis is an autosomal dominant neurocutaneous disorder that occurs due to a mutation in either TSC1 (encoding hamartin) or TSC2 (encoding tuberin). Mutations in TSC1 or TSC2 predispose children to the development of cortical hamartomas which eventually lead to CNS symptoms. Patients with tuberous sclerosis are also at an increased risk of developing retinal hamartomas, cardiac rhabdomyomas, and renal angiomyolipomas. Cardiac rhabdomyomas are the most common cardiac tumors in children and their presentation can range from fetal demise to signs of outflow obstruction to an incidental finding.

Figure A demonstrates the characteristic appearance of an ash leaf spot in a patient with tuberous sclerosis. These spots are hypopigmented macules that may appear anywhere on the body and are caused by decreased levels of melanin in the skin. They are often best visualized under a Wood's lamp (ultraviolet light).

Incorrect Answers:
Answer 1: Pilocytic astrocytoma is a benign CNS tumor composed of astrocytes. It is the most common childhood primary brain tumor and primarily occurs in children between 8 and 13 years old.

Answer 3: Medulloblastoma is a malignant tumor arising from the medulla. It can present with hydrocephalus if the tumor blocks outflow through the fourth ventricle just inferior to the medulla.

Answer 4: Nephroblastoma, also known as Wilms’ tumor, is the most common type of kidney cancer in children. Children with Wilms tumor-aniridia-genitourinary malformation-retardation (WAGR) syndrome and Denys-Drash syndrome are at an increased risk of developing nephroblastoma.

Answer 5: Hepatoblastoma is a rare malignant tumor arising from the liver. It is the most common form of liver cancer in children and primarily occurs in children between infancy and five years of age. Children with Beckwith-Wiedemann syndrome and familial adenomatous polyposis are at an increased risk of developing hepatoblastoma.

Bullet Summary:
Cardiac rhabdomyomas are the most common cardiac tumor in children and their presentation depends on the degree of obstruction of cardiac valves or chambers. Children with tuberous sclerosis are at an increased risk of developing cardiac rhabdomyomas.