Intense Pituitary 18F-Fluorodeoxyglucose Positron Emission Tomography Uptake in a Patient with Diabetes Insipidus

• Published in: Balkan medical journal Vol. 36; no. 4; pp. 253 - 254
• Main Authors: Soydal, Çiğdem, Nak, Demet, Araz, Mine, Taçyıldız, Nurdan, Küçük, Nuriye Özlem
• Format: Journal Article
• Language: English
• Published: Turkey Galenos Yayinevi Tic. Ltd 01.07.2019; Trakya Üniversitesi; Aves Yayincilik Ltd. STI; Galenos Publishing; Galenos Publishing House
• Subjects: Child; Clinical Image; Contrast Media - therapeutic use; Diabetes; Diabetes insipidus; Diabetes Insipidus, Neurogenic - blood; Diabetes Insipidus, Neurogenic - complications; Diabetes Insipidus, Neurogenic - diagnosis; Diabetics; Electrolytes; Fluorodeoxyglucose F18 - analysis; Fluorodeoxyglucose F18 - blood; Humans; Magnetic Resonance Imaging - methods; Male; Medical imaging; NMR; Nuclear magnetic resonance; Patients; Pituitary gland; Pituitary Gland - abnormalities; Pituitary Gland - diagnostic imaging; Pituitary Gland - physiopathology; Positron emission tomography; Positron-Emission Tomography - methods; Tıp; Tomography; Urination disorders; Urine; Türkiye; Edirne; Ankara Turkey; Turkey; 18F-Fluorodeoxyglucose
• ISSN: 2146-3123; 2146-3131
• DOI: 10.4274/balkanmedj.galenos.2019.2019.4.3

This case discusses a 6-year-old male patient with a two-month history of polyuria and polydipsia (3800-4000 cc/d). The patient's 24-hour urine osmolality was 79 mOsm/kg, and it increased to 98 mOsm/kg; he lost 5.2% of his weight after 7-hour water deprivation test. The urine osmolality increased from 98 to 472 mOsm/kg at the 4th hour of 10 mcg desmopressin test. Moreover, his renal functions were normal, his polyuria and polydipsia resolved on treatment with 60 μg desmopressin twice daily, and his electrolyte levels were in the normal range. The patient was diagnosed with central diabetes insipidus. Pituitary profile was in a reasonable limit, except for prolactin, which was 32 ng/dL that was slightly higher than the upper limit. Gadolinium-enhanced magnetic resonance imaging of the pituitary showed contrast-enhanced lesions in the brainstem, prominently in the pons, with diffusely increased intensity on T2 sequence and limited diffusion. Lesions had right cerebellar and left cerebral extensions. Magnetic resonance imaging also revealed heterogenous pituitary gland, thickened stalk, and loss of a hot signal (T1 weighted) of the posterior pituitary, which was suggestive of Langerhans cell histiocytosis. Cerebral fluid sampling and pituitary stalk biopsy were considered deferred. Maximum intensity projection 18F-fluorodeoxyglucose positron emission tomography (Figure 1a) images of the patient revealed pathological uptakes in cranium, thorax, and the left pelvic region. Fused trans-axial images demonstrated pathological uptakes located in the pituitary gland (SUVmax: 9.8) (Figure 1b), soft tissues in the anterior mediastinum (SUVmax: 10.7) (Figure 1c), and the left acetabular region (SUVmax: 10.6) (Figure 1d). Written informed consent was obtained from the parents.