IMPE Abstracts

Introduction: Intracranial germ cell tumors (iGCTs) are rare neoplasms that mainly affect adolescents and young adults. iGCTs are divided into germinoma and non-germinomatous germ cell tumors. The hypothalamic-pituitary region is the second primary site of iGCTs after the pineal region. The iGCTs with isolated pituitary stalk involvement are rare and difficult to diagnose. They should be suspected when there is a pituitary stalk thickening >6.5 mm or a coexistence of diabetes insipidus and hypopituitarism.

Methods: During the pandemic of COVID-19, we observed an increased frequency in the diagnosis of pediatric patients with germinoma with isolated pituitary stalk involvement in Chile, compared with previous years. A multicentric retrospective study was performed. We analyzed clinical, radiological and histological data on pediatric patients with confirmation of germinoma with isolated pituitary stalk involvement that presented during COVID-19 pandemic, recruited from different centers in our country.

Results: Eight patients were diagnosed with germinoma with isolated pituitary stalk involvement during the pandemic of COVID-19 in Chile, most of them were girls (87,5%). The mean age at diagnosis was 11,35 years. All patients presented with polydipsia and polyuria and 87,5% with alterations in growth. Sixty two percent had neuro-ophthalmologic symptoms. All patients had growth hormone deficiency (GHD) and central diabetes insipidus (CDI). Three quarters of patients had central hypothyroidism and hyperprolactinemia. Tumor markers (aFP and b-HCG) were negative in serum and cerebrospinal fluid in all patients. The median of the maximum diameter of the pituitary stalk was 8.1 mm and 62,5% had optic chiasm compromise on MRI. All patients went to biopsy to confirm the diagnosis and 37,5% required a second biopsy because the first one was informed with hypophysitis.

Discussion: We observed an increase in the frequency of germinoma with isolated pituitary stalk involvement during the pandemic of COVID-19 in Chile, compared with previous years. In this study we found more girls opposite to other series. All patients had GHD and CDI with negative tumor markers. An important percentage of patients required a second biopsy because of a histological diagnosis of hypophysitis. It’s important to acknowledge that this is a rare diagnosis in pediatric patients and that germinomas generate a peritumoral inflammatory reaction. Thus, the diagnosis of germinoma remains challenging, and it’s important to establish new markers to assess these patients, because delayed diagnosis can increase the risk of progression. Early diagnosis and appropriate treatment is a key factor in reducing mortality and complications.