Unilateral group B retinoblastoma
B. Plan an urgent examination under anesthesia, ultrasonography, and magnetic resonance imaging (MRI).
The differential diagnosis includes retinoblastoma, retinocytoma, astrocytic hamartoma, toxocara granuloma, or toxoplasmosis. Retinoblastoma must be ruled out in any child with leukocoria or a posterior segment mass. An examination under anesthesia (choice B) is needed for a scleral depressed examination, ultrasonography (because a calcified retinal tumor is pathognomonic), and MRI with contrast to assess the eyes, optic nerves, orbits, and brain. A uveitis workup (choice A) is inappropriate because the patient had no intraocular inflammation, and this approach does not further investigate the mass. Imaging for tuberous sclerosis (choice C) is not indicated, because the lesion is more concerning for retinoblastoma than astrocytic hamartoma, which in young patients usually presents with gray-white or translucent, noncalcified retinal lesions. Clinical observation (choice D) is inappropriate for a potentially neoplastic posterior segment mass.