Brain Pathology Case of the Month - November 2019

Contributed by Zhiwei Shen, PhD; Xinjie Bao, MD; Renzhi Wang, MD
Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China


CLINICAL HISTORY

A 13-year-old girl presented with polyuria, headache, drowsiness, and worsening vision. She reported that polyuria initially occurred 5 years before the consultation, headache and drowsiness developed 3 months earlier, and vision in both eyes had deteriorated dramatically over the previous 1 month. She was subsequently referred to our clinic for further evaluation and treatment. Coronal contrast magnetic resonance imaging (MRI) of the pituitary in our hospital revealed a giant sellar and suprasellar mass with "hourglass sign", measuring 25 42.2 23.7 mm. The mass had no cystic areas and was heterogeneously enhanced by gadolinium, suggesting a pituitary adenoma (Figure 1a). She denied nausea, vomiting, lactation, acromegaly, and central obesity. Her first menstrual cycle had not yet occurred, and her growth and development were normal. Neurological examination revealed bilateral pupillary dilation of OD 8 mm and OS 6 mm, with pupillary light reflex depressed in both eyes. Baseline pituitary function evaluation revealed primary hypothyroidism (thyroid-stimulating hormone: 7.17 μIU/ml, free-T4: 0.454 ng/dl), hypocortisolism (cortisol < 0.50 μg/dl), decreased somatotropin (growth hormone: 0.1 ng/ml, insulin-like growth factor: 133ng/ml), decreased estradiol with low gonadotropins (estradiol: 13.32 pg/ml, follicle-stimulating hormone: 0.20 IU/L, luteinizing hormone: < 0.2 IU/L). However, her prolactin, β-human chorionic gonadotropin, and α-fetoprotein levels were normal. Based on these findings, panhypopituitarism secondary to a nonfunctioning pituitary macroadenoma was highly suspected and presumptively treated. The patient underwent right frontal craniotomy using a coronal incision for tumor resection and optic chiasm decompression. Visual acuity recovered soon after surgery.

MICROSCOPIC PATHOLOGY

Histopathological examination revealed large round neoplastic cells with amounts of clear cytoplasm and prominent vesicular nuclei with plump nucleoli (H&E, Figure 1b). Immunohistochemical staining revealed tumor cells positive for c-kit (Figure 1c), placental alkaline phosphatase (Figure 1d), SALL4 (Figure 1e) and Oct3/4 (Figure 1f). What is your diagnosis?

FINAL DIAGNOSIS


International Society of Neuropathology