Cerebral germinoma revealed through a polydipsic polyuric syndrome in a 10-year-old girl: case report

Abstract

Cerebral germinoma is rare. Although the imaging of the germinoma is very evocative, it's very polymorphic clinical expression is at the origin of misguided diagnosis, as illustrated in our case. We report the case of a 10-year-old girl with diabetes insipidus evolving for 12 months associated with a decrease in visual acuity. Brain MRI (Magnetic Resonance Imaging) revealed a tumor process in the suprasellar region. Th e stereotaxic biopsy of the tumor confi rmed the diagnosis of the hypothalamic germinoma, which allowed the patient to be treated by radiotherapy and chemotherapy. Th e incidence of cerebral germinoma, its clinical (principally diabetes insipidus) and radiological features as well as therapeutic strategies are discussed hereby. Th e cerebral germinomas are germ-line tumors representing 4% of childhood brain tumors (Resetkova et al. 2013). We report a new observation of cerebral germinoma discovered through a polyuric polydipsic syndrome. Th e literature has been reviewed with discussion of the diagnosis, the radiological criteria, and the treatment of these tumors. Key words: diabetes insipidus, panhypopituitarism, intracerebral germinoma Subject and ResultsA 10-year-old girl was hospitalized in the pediatric neurology unit for drowsiness and cognitive disorders. She also complained of frontal headaches and progressive polyuric polydipsic syndrome (drinking between 3 and 7 liters per day), associated with growth failure. Medical history was unremarkable, except for a defi cit in Von Willebrandt factor detected during the pre-operative exams for adenoids. Th e clinical examination was normal; no sign of puberty was observed. A blood sample analysis showed a low free T4 (fT4) level at 7.4 pmol/l (reference 10.4-24.0 pmol/l) with normal t hyroid stimulating hormone (TSH) at 3.7 mU/l (reference 0.70-5.3 mU/l), increased level of prolactin at 63.3 μg/l (reference 5.0-23.0 μg/l), and low levels of gonadotropins. Plasma sodium and glucose were within the normal range. Th erefore, central hypothyroidism and diabetes insipidus (DI) were suspected. Urine osmolality was low at 88 mOsm/kg (reference 300-900 mOsm/kg), while plasma osmolality was normal at 281 mOsm/kg. A hydric deprivation test was not performed because the polyuric polydypsic syndrome was severe (3 to 7 liters per day). Th e concentration of anti-diuretic hormone (ADH) was low <0.5 pg/ml (reference 0.5-14 pg/ml) confi rming the DI. A glucagon test was performed (Table 1) to explore the anterior pituitary, there was no signifi cant increase of plasma cortisol and growth hormone (GH) levels aft er stimulation. Th e defi cit in fT4 and cortisol were treated by L-Th yroxine® 50 μg/day and hydrocortisone, while DI was successfully treated by Minirin®.