Intracranial germ cell tumors: a view of the endocrinologist

Intracranial germ cell tumors (iGCTs) are rare malignant neoplasms that mainly affect children and adolescents. The incidence, clinical presentation, and prognosis of iGCTs exhibit high heterogeneity. Previous studies have primarily focused on eliminating tumors, reducing tumor recurrence, and improving survival rates, while neglecting the impact of the tumors and their treatment on neuroendocrine function. Throughout the entire course of the disease, neuroendocrine dysfunction may occur and is frequently overlooked by oncologists, neurosurgeons, and radiologists. Endocrinologists, however, are more interested in this issue and have varying priorities at different stages of the disease. From onset to the diagnostic phase, most patients with iGCTs may present with symptoms related to impaired neuroendocrine function, or even experience these symptoms as their first indication of the condition. Particularly, a minority of patients with sellar/suprasellar lesions may exhibit typical imaging features and elevated tumor markers long after the onset of initial symptoms. This can further complicate the diagnosis process. During the peritumor treatment phase, the neuroendocrine function shows dynamic changes and needs to be evaluated dynamically. Once diabetes insipidus and dysfunction of the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-thyroid axes occur, hormone replacement therapy should be administered promptly to ensure successful tumor treatment for the patient. Subsequently, during the long-term management phase after the completion of tumor treatment, the evaluation of growth and development as well as corresponding hormone replacement therapy are the most concerning and complex issues. Thus, this paper reviews the interest of endocrinologists in iGCTs at different stages.

Hormone replacement in survivors of childhood cancer and brain tumors: safety and controversies

Childhood cancer survivors are at risk for developing endocrine disorders, including deficits in growth hormone, thyroid hormone and sex hormones. The influence these hormones have on cell growth and metabolism has raised concerns regarding the safety of their use as treatments in survivors of childhood cancer and brain tumors. This article offers a summary of current knowledge, controversies and areas for future research pertaining to this area.

Precocious puberty due to intracranial germ cell tumors: a case-control study

Children with intracranial germ cell tumors may present premature sexual development via either gonadotrophin-releasing hormone (GnRH)-dependent cause or GnRH-independent cause. We conducted a single-center retrospective study on 37 precocious puberty (PP) patients with intracranial germ cell tumors and 25 age-matched prepubertal patients with elevated human chorionic gonadotropin (hCG) levels. Classification of PP was derived from hCG, gonadotropin and sex steroid levels and their changes. Five boys were assigned to GnRH-dependent group (G1). Thirty-one boys and one girl were assigned to GnRH-independent group (G2) with a median hCG of 76.75 (8.29-2747) IU/L. Seven boys and 18 girls were conducted as controls, with a median hCG of 17.12 (2.91-1062) IU/L. Patients in G1 had constant pubertal LH and testosterone levels after tumor complete response. Patients in G2 had hCG levels that decreased simultaneously with testosterone/estradiol levels, prior to tumor regression. The differences in hCG levels and the gender ratio were significant between G2 and controls (P = 0.006 and P < 0.001, separately). Among intracranial germ cell tumor patients with positive hCG, boys with significantly higher hCG levels more easily developed PP. Our results suggest that GnRH-independent PP commonly regresses together with tumor regression. In comparison, results were inconclusive in tying tumor regression to the regression of GnRH-dependent PP.

Revisiting the pineal gland: a review of calcification, masses, precocious puberty, and melatonin functions

Introduction: The pineal gland, an endocrine organ of the posterior cranial fossa famously involved in sleep and wakefulness, has continually been a topic of scientific advancement and curiosity. Methods: We review present an up-to-date review including the anatomy, embryology, and physiology of the pineal gland and its ability to secrete hormones including melatonin, pathophysiology of pineal gland tumors, cysts, and calcifications, their clinical presentation including their association with parkinsonism and precocious puberty, and various treatment approaches. Results: Exploring the biochemistry of melatonin, various calcification morphologies, and pineal tumors may uncover a wider role and the exhaustive case study consolidation allows clinicians to carefully review the literature and aid their treatment approaches. Conclusion: It is imperative that clinicians and diagnosticians are able to distinguish manifestations of an overlooked gland.

Pure germinoma occurring 11 years after total pineal mature teratoma removal: a case report and review of the literature

Intracranial mature teratomas have good prognoses and are usually treated by total tumor resection. We report a rare case of a germinoma that occurred 11 years after total removal of a pineal mature teratoma. A 5-year-old boy presented with headache and nausea and was diagnosed with a pineal tumor and obstructive hydrocephalus on MRI. He underwent total removal of the lesion, which was pathologically diagnosed as a mature teratoma without any other germ cell tumor components. MR images after 11 years showed a newly developed pineal tumor, which was confirmed as a germinoma after neuroendoscopic biopsy. Chemoradiotherapy resulted in complete remission, without any symptoms. This case demonstrated possible late occurrence of germinoma even after total removal of a mature teratoma had been achieved. A long-term follow-up of 10 years or more should be planned for these patients.

De Novo Pineal Region Germinoma in the Seventh Decade of Life: A Case Report

Germ cell tumors typically occur in children and adolescents. We here report a rare case of de novo pineal region germinoma in the seventh decade of life. A 62-year-old man presented with double vision. Computerized tomography and magnetic resonance imaging (MRI) identified a heterogeneously enhanced tumor with calcification in the pineal region with ventricular dilatation due to aqueduct stenosis. The tumor had not been observed at all on MRI obtained 2 years previously. The patient underwent endoscopic biopsy and third ventriculostomy for the obstructive hydrocephalus. The tumor was histopathologically diagnosed as a pure germinoma. The patient underwent radiomonotherapy, resulting in his complete remission, which was confirmed by a series of follow-up MRI studies and hematological examinations. Intracranial germinoma should be considered in the differential diagnosis of pineal region tumors regardless of age, even though the tumor was undetectable on the previous neuroimaging.

Extremely Late Recurrence 21 Years after Total Removal of Immature Teratoma: A Case Report and Literature Review

Immature teratoma (IMT) is normally treated by resection and adjuvant therapy. The present unusual case of recurrent germinoma occurred 21 years after total resection of pineal IMT. A 3-year-old boy presented with headache, disturbance of consciousness, and Parinaud's syndrome. Magnetic resonance (MR) imaging revealed a pineal mass lesion, and total resection of the tumor was achieved. The histological diagnosis was mature teratoma. He did not receive further treatment, and did well without recurrence for 20 years. However, he suffered headache 21 years after resection, and MR imaging revealed a homogeneously enhanced pineal mass with low minimum apparent diffusion coefficient value and proton MR spectroscopy showed a huge lipid peak. The levels of tumor markers were not elevated. Cerebrospinal fluid (CSF) cytology found atypical cells with large nuclei and irregularly shaped nucleoli. To elucidate the relationship between the primary and recurrent tumors, we reviewed the histological specimens and CSF cytology at the initial treatment and found a subset of incompletely differentiated components resembling fetal tissues in the histological specimen and atypical large cells in the CSF. Based on these radiological and histological findings, we presume that the recurrent disease was disseminated germinoma after the resection of disseminated IMT. He received chemotherapy and craniospinal radiation therapy, and the enhanced lesion and atypical cells in the CSF disappeared. This case demonstrates that disseminated IMT can be controlled for the long term without adjuvant therapy, but may recur as germinoma. Tumor dormancy may account for this unusual course.

Rapid enlargement of an intracranial germ cell tumor after gonadotropin hormone therapy

We report a case of an intracranial germ cell tumor (iGCT) that showed rapid enlargement after human chorionic gonadotropin (hCG) hormone therapy for pituitary hypogonadism. A 16-year-old boy presented with headache and was diagnosed with a suprasellar tumor. He was initially observed without surgery. Intranasal desmopressin therapy was started for central diabetes insipidus, but there was no change in the tumor size on MRI. The diagnosis of the tumor remained unknown for 4years. Levels of serum gonadotropin hormones (follicle-stimulating and luteinizing hormone) and testosterone progressively decreased, and the patient developed pituitary hypogonadism and complained about his undeveloped beard, lack of underarm hair, and erectile dysfunction. Intramuscular gonadotropin injection (hCG 5000U×2/week) was started at age 20. Eight months after the first gonadotropin injection, the MRI showed tumor growth with vivid enhancement. Craniotomy was performed and the tumor was partially resected. The histological diagnosis was immature teratoma. After surgery, the patient was treated with 5 cycles of chemotherapy with carboplatin and etoposide. He also received radiation therapy of 50Gy (20Gy tumor bed and 30Gy whole ventricles) to the residual tumor, after which the tumor decreased in size. We postulate that iGCT may be at risk of progression during hCG hormone therapy. Thus, careful monitoring is required for a patient with iGCT who receives this therapy.