Tumors of the posterior third ventricular region in pediatric patients: The Indian perspective and a review of literature.

BACKGROUND: Diverse tumors in the posterior third ventricular region (TPTVR) frequently occur in children. A decade's experience with pediatric TPTVR is presented, focusing on the Indian perspective.

MATERIALS AND METHODS: 25 children (age range: 3-18 years; mean age: 13.32 years; presentation range: 7 days-2.5 years) had clinico-radiological assessment with contrast computed tomography (CT) and magnetic resonance imaging (MRI). The ventricular/lumbar cerebrospinal fluid (CSF) alpha feto protein (AFP)/beta human chorionic gonadotrophin (HCG) estimation was done when radiological suspicion of a germ cell tumor was present. Extent of resection was deemed partial when some tumor mass remained at the end of surgery, near total when <10% was retained over vital neurovascular structures, and total when complete resection was attained.

RESULTS: Operations included infratentorial supracerebellar approach (n = 12), occipito-transtentorial approach (n = 2), endoscopic biopsy and third ventriculostomy (n = 1), frontal parasagittal craniotomy, interhemispheric transcallosal subchoroidal approach (n = 2), middle temporal gyrus transcortical transventricular approach (n = 1), fronto-temporo-zygomatic combined transylvian and subtemporal approach (n = 1) and right ventriculoperitoneal shunt and stereotactic biopsy (n = 1). Only CSF diversion was performed for five patients with a small TPTVR. CSF diversion was required in 12 (48%) patients. Tumor pathology included pinealoblastoma (n = 4; one with pineocytic differentiation), nongerminomatous germ cell tumor (NGGCT; n = 3), germinoma (n = 3), pilocytic astrocytoma (n = 2), epidermoid (n = 3) and primitive neuroectodermal tumor (PNET), fibrillary astrocytoma, glioblastoma, teratoma, and meningioma (n = 1, respectively). A patient with neurocysticercosis was diagnosed solely on MRI (four did not undergo biopsy). Fractionated radiotherapy was administered in 13 patients with primary pineal tumors, PNET, NGGCT, fibrillary astrocytoma and glioblastoma. Extent of excision was total in 10 (40%), near total in 5 (20%), partial in 3 (12%) and a biopsy in 2 (8%) patients.

CONCLUSIONS: Histopathologic characterization of TPTVR is essential prior to their further management. Benign lesions often have a good prognosis following gross total surgical resection. Pure germinomas are highly susceptible to radiotherapy. NGGCTs often have malignant components that require adjuvant therapy following surgery. The advancements in microsurgical techniques have led to gratifying perioperative results in these deep-seated lesions.