ESPE Abstracts

Introduction: Pilocytic astrocytoma is the most common type of CNS astrocytoma in children. Clinical manifestations depend on its location and size and initial symptoms are usually related to neurological deficits or signs and symptoms of intracranial hypertension. Involvement of the hypothalamic area, pituitary infundibulum and leptomeningeal spread are exceptional. The case of a patient with central precocious puberty in whom the initial neuroimaging study oriented the diagnosis of a dysgerminoma with meningeal metastases is presented. Arachnoid biopsy of the nodular lesion was diagnostic of leptomeningeal dissemination of a pilocytic astrocytoma.

Case report: A 4-year-old boy was referred for study of pubic hair of 3 months’ evolution with no other accompanying symptoms. Family and personal history normal. Physical examination: weight: 17.5 kg (−0.7 S.D.), height: 116.8 cm (+2.4 S.D.), Tanner: G1P2, testicular volume: 4–5 cc, bone age: 4 years, 6 months. Basal hormonal study: adrenal androgens and thyroid hormones: normal. LHRH test: basal LH: 1.4 IU/l; peak LH: 23.0 IU/l and basal FSH: 2.3 IU/l, peak: 4.4 IU/l, testosterone: 65.9 ng/dl, prolactin: 6.0 ng/ml, IGF −1: 139.2 ng/ml, ACTH: 52.4 pg/ml, basal cortisol: 15.0 μg/dl and urine osmolarity after a dry dinner: 875 mOsm/kg. Study of serum tumour markers (α-fetoprotein and hCG β subunit): negative. Brain MRI: hypothalamic thickening with left predominance, consistent with germ cell tumour. Nodular images of supra- and infratentorial leptomeningeal dissemination. Lumbar puncture: cytochemical study normal, acellular cytology: and CSF tumour markers: negative. Arachnoid biopsy: leptomeningeal tissue containing a nodule with tumour cells expressing GFAP and p16. Ki67 below 3%. Epithelial markers: negative. Diagnosis: pilocytic astrocytoma with leptomeningeal dissemination.

Conclusions: Hypothalamic and infundibular involvement of pilocytic astrocytoma and its association with central precocious puberty are exceptional. This entity should be considered in the differential diagnosis of infiltrative processes of the hypothalamus and pituitary infundibulum.