Background: Polyuria and polydipsia must never be underestimated.
Objective and hypotheses: A 7-year-old girl presented with polyuria, polydipsia and nocturia of 1 year duration, during which she underwent outpatient follow up with her general practitioner and urologist. No weight loss or other endocrine signs.
Method: Polyuria was confirmed by water balance (120 ml/kg per 24 h), urinary osmolality (222 mmol/kg), plasma osmolality (296 mmol/kg), and U-Osm/S-Osm (0.75). During water deprivation test (WDT) urine osmolarity partially increased without desmopressin, plasma osmolarity, and sodium were stable. WDT revealed a partial DI, no other hormone deficits were diagnosed. For a second opinion, she was admitted in our center. An MRI was performed which showed thickening of the pituitary stalk and the lack of posterior pituitary hyperintensity. Diffuse pathological enhancement of the optic chiasm and optic nerves was shown. Hypothesis: chronic inflammatory granulomatosis disease suspect for Langherans-cell histiocytosis (LCH). No other organs were involved. Cerebrospinal fluid: negative for β-HCG and α-fetoprotein.
Results: The patient was discharged with sublingual desmopressin acetate treatment and the water balance progressively improved. At 1 month of follow-up, the patient presented neurological deterioration (decline in school performance, difficulty in concentration, and memory). Brain MRI showed worsening of the neuroradiological features with a neurodegenerative pattern of the white matter. There was no apparent involvement of the cerebellum, which instead is a typical complication of LCH. Bioptic evaluation of the pituitary stalk was compatible with a germinoma.
Conclusion: This case shows the importance of performing brain MRI and to successively evaluate the need for bioptic examination. If the cause should remain unclear, tumors should always be excluded. Furthermore, the thickening of the stalk and the inflammatory aspect initially led to hypothesize LCH, but may also have been suggestive of germinoma. Therefore, this neuroradiological aspect should be monitored in time. Finally, the neurodegenerative component (paraneoplastic or dysimmune) is an atypical presentation of germinoma and may be misleading.
20 - 22 Sep 2014
European Society for Paediatric Endocrinology