Resolution of precocious puberty following resection of fourth ventricular medulloblastoma: case report

Medulloblastoma is a malignant embryonal tumor that arises in the cerebellum and invades the fourth ventricle, often resulting in obstructive hydrocephalus. Patients typically present with symptoms related to increased intracranial pressure and cerebellar dysfunction. The authors report a rare case of classic medulloblastoma with central precocious puberty (CPP) as its only presenting symptom. A 7-year-old boy with no prior history of medulloblastoma presented with Tanner Stage IV testicular enlargement and a 4-month history of acne and pubic hair. Laboratory tests of blood samples demonstrated highly elevated luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone. Admission MRI of the brain revealed a mass in the posterior fossa, which bordered and compressed the fourth ventricle. The patient also exhibited mild lateral and third ventriculomegaly. Surgical options were discussed with the neurosurgical department. A suboccipital craniotomy and C-1 laminectomy were performed. A large mass was seen arising from the inferior surface of the vermis, and lying within the fourth ventricle. Gross-total microsurgical resection of the mass was performed. Histopathological investigation characterized the tumor as classic medulloblastoma. Follow-up laboratory tests of blood samples demonstrated a reduction of LH, FSH, and testosterone back to prepubertal levels. The patient then began radiation and chemotherapy. This report demonstrates that mild obstructive hydrocephalus due to a posterior fossa tumor may present with unexpected symptoms, such as CPP. To the authors' knowledge, precocious puberty has not yet been associated with medulloblastoma, although it has been found with other posterior fossa tumors. Extensive imaging of the CNS for patients presenting with CPP is recommended.