We describe multidisciplinary management of a pregnant woman with presumed hormone related, WHO grade 1 juvenile pilocytic astrocytoma (JPA) growth.

JPA typically occurs before age 20 years, equally among genders, and in cerebellum. JPA-associated BRAF alterations include 10-15% BRAF/V600E mutations and 60-80% BRAF/KIAA1549 fusions. Lack of female predominance argues against estrogen sensitivity as seen with meningiomas or diffuse gliomas. JPA molecular analysis identified microRNAs target MAPK and NF-κB pathways, while estrogen receptor inhibited. 

A 31-year-old G2P1 woman with JPA presented emergently with headache, lethargy, aphasia, hemiparesis, and increased intracranial pressure. Diagnosed at age 25 years via biopsy with thermal ablation of an inoperable2.8x2.3x2.3cm left thalamocapsular mass, she enrolled on a MEK inhibitor trial for confirmed BRAF/KIAA1549 fusion, discontinued after 4 days due to intratumoral hemorrhage. While minimal growth to 2.8x2.5x2.2cm was noted at 10EGA, noncontrast brain MRI by 30EGA revealed growth to >4cm³, edema, obstructive hydrocephalus, and transependymal edema. After corticosteroids for fetal lung maturation, emergent C-section delivered a 3lb/11oz baby at EGA 31^2/7, safely discharged after NICU monitoring.

After minimal improvement on high-dose dexamethasone, left parietal craniotomy at 5 days postpartum resulted in subtotal tumor resection. Two days later, she required emergent craniotomy for intraparenchymal hemorrhage, resulting in gross total resection. Pathology confirmed WHO grade 1 JPA, notably negative for estrogen/progesterone receptors. Postoperative significant mixed aphasia and right hemiparesis improved with rehabilitation. No radiation advised after serial MRIs at 3-6 months postpartum confirmed no residual tumor.

Noncontrast MRI with max 3T magnet is safe and ideal imaging during pregnancy as CT exposes fetuses to radiation, worsened by abdomen shielding due to internal scatter (ACR guidelines). Gadolinium is secreted into amniotic fluid, thus avoided during pregnancy. Gross total resection, even at recurrence after medical or radiotherapy, is curative and thus remains the mainstay intervention for JPA.