Endocrine Abstracts

JOINT2683

Introduction: Growth hormone (GH) deficiency and pituitary stalk diseases are rare but significant conditions in pediatric endocrinology. However, distinguishing between infundibulohypophysitis and germinoma is crucial, as their management differs significantly—infundibulohypophysitis requires glucocorticoid pulse therapy, whereas germinoma necessitates alternative oncological treatment. In this case, a biopsy is necessary to determine the nature of the lesion.

Objective: This case highlights the importance of accurate differential diagnosis and a multidisciplinary approach in managing patients with GH deficiency.

Case: A 13-year-old girl was referred to the endocrinology department for evaluation of growth retardation, polydipsia, and polyuria, first noted at age 9. During examination height SDS was -3.43, BMI SDS was -2.49, and the bone age was 9–10 years. Karyotyping confirmed a 46XX genotype. Initial evaluations raised a suspicion of diabetes insipidus. Brain magnetic resonance imaging suspected lymphocytic infundibulohypophysitis. Laboratory investigations showed slightly elevated prolactin levels: 39.45 ng/ml (N <23.3 ng/ml), reduced IGF-1: 73.6ng/ml (IGF-1 SDS= -3). Other autoimmune diseases, including celiac disease, were ruled out. A comprehensive immunological panel yielded no abnormalities. Neuroendocrinological assessments included alpha-fetoprotein and beta-human chorionic gonadotropin (β-hCG), both of which were normal. Considering the possible autoimmune nature of the underlying disease, the IgG4 level was assessed and found to be normal. Growth hormone (GH) deficiency was confirmed following two stimulation tests. The arginine stimulation test revealed a peak GH level of 1.57 ng/ml, while the insulin test showed a maximum GH level of 1.03 ng/ml, both below the normal range. Cortisol levels were within normal limits during the initial testing; however, during hypoglycemia, cortisol did not appropriately increase, leading to a diagnosis of subclinical hypocorticism. With water deprivation test urine specific gravity was 1015, which ruled out diabetes insipidus. But one month later she was readmitted with persistent polyuria, polydipsia, and weight loss. To address these symptoms, desmopressin treatment was initiated to evaluate its effectiveness. A lumbar puncture was also performed, AFP and HCG were determined in the lumbar exudate to rule out germinoma, and no abnormalities were found. She started treatment with GH. A follow-up MRI is planned three months later to evaluate the size of the suspected mass.

Conclusions: This case underscores the importance of a thorough and systematic approach in the diagnosis of growth retardation and suspected hypopituitarism. As we were unable to perform a biopsy, a repeat MRI is necessary to further evaluate the pituitary mass.