Most cases of optic hypothalamic
pilocytic astrocytoma (
OHPA) develop during childhood, so few cases of histologically verified
OHPA have been described in adolescents and young adults (AYA). To elucidate the clinical features of
OHPA with histological verification in AYA, we reviewed the clinical and radiological finding of
OHPA treated at our institute from January 1997 and July 2017. AYA are aged between 15 and 39 years. The clinical courses of 11 AYA patients with optic hypothalamic
glioma (OHG) without
neurofibromatosis type 1 were retrospectively reviewed. About six patients were diagnosed in childhood and followed up after 15 years of age, and five patients developed
OHPA during AYA. Histological diagnosis, verified at initial presentation or recurrence, was
pilocytic astrocytoma in 10 and pilomyxoid
astrocytoma in one. After initial treatment including debulking surgery and/or
chemotherapy,
tumor progression occurred 16 times in seven patients as
cyst formation,
tumor growth, and intratumoral
hemorrhage. Five of 10 patients suffered deterioration of visual function during AYA. One of 10 cases had endocrinopathies requiring
hormone replacement at last follow-up examination. In conclusion, histological diagnoses of OHG before and in AYA were
pilocytic astrocytoma or pilomyxoid
astrocytoma. Both pediatric and AYA-onset
OHPA demonstrate high incidences of
tumor progression and visual dysfunctions in AYA, so that long-term follow up is essential after the completion of treatment for pediatric and AYA-onset
OHPA. The optimal timing of debulking surgery and
radiation therapy should be established to achieve the long-term
tumor control and to preserve the visual function.