Morphologic features of human chorionic gonadotropin- or alpha-fetoprotein-producing germ cell tumors of the central nervous system: histological heterogeneity and surgical meaning

Long-term consequences of residual lesions after chemoradiotherapy in patients with germinoma at onset

OBJECTIVE

In patients with intracranial germ cell tumors, residual lesions are sometimes observed after completion of primary chemoradiotherapy. Although salvage resection of these end-of-treatment residual lesions is recommended for patients with nongerminomatous germ cell tumors, the necessity of early salvage resection for those with germinoma is not clear. The aim of this study was to investigate the frequency of residual germinoma lesions after primary chemoradiotherapy, as well as their management, long-term consequences, and prognosis.

METHODS

The authors retrospectively reviewed patients who were primarily treated for germinoma between 2002 and 2021. Residual lesions were evaluated with MRI with and without contrast enhancement within 2 weeks after chemoradiotherapy. The decision to perform salvage resection of residual lesions was at the discretion of the treating physicians. The change in appearance of residual lesions was assessed with serial MRI. Overall survival (OS), progression-free survival (PFS), and recurrence pattern were also investigated.

RESULTS

Sixty-nine patients were treated with chemoradiotherapy for germinoma, with a mean follow-up period of 108 months. Residual lesions were radiologically observed in 30 patients (43.5%). Among these, 5 patients (3 with pineal lesions and 2 with basal ganglia lesions) underwent salvage resection. Pathological examination revealed teratomatous components in 3 patients, whereas no tumoral components were identified in 2 patients. One patient with a basal ganglia lesion showed worsening of hemiparesis postoperatively. The remaining 25 patients received watchful observation without surgical intervention. Chronological periodic radiological change in residual lesions was evaluated in 21 patients. One year after primary treatment, the size of the residual lesions was stable and had decreased in 10 and 11 patients, respectively. None of the lesions increased in size. The 10-year PFS and OS rates were 96.7% and 97.3% in patients without residual lesions (n = 39), and 87.1% and 100% in patients with residual lesions (n = 30), respectively. Presence of residual lesions had no significant effect on PFS or OS. All recurrences occurred at distant sites or via dissemination without progression of the primary tumor site, regardless of the presence of residual lesion.

CONCLUSIONS

End-of-treatment residual lesions are not rare in patients with germinoma, and these residual lesions seldom show progression. Because of the potential risk of surgical complications, the indication for early salvage surgery for residual lesions should be carefully determined. Watchful observation is recommended for the majority of these cases.

A clinical approach to parasellar lesions in the transition age

Many reviews have summarised the pathology and management of the parasellar region in adult patients, although an analysis of these aspects in the transition years, from puberty onset to the age of peak bone mass, has been lacking. A comprehensive search of English-language original articles, published from 2000 to 2020, was conducted in the MEDLINE database (December 2019 to March 2020). We selected all studies regarding epidemiology, diagnosis and management of the following parasellar lesions: germinoma, craniopharyngioma, Langerhans cell histiocytosis, optic glioma, hypothalamic hamartoma, tuber cinereum hamartoma, cranial chordoma, Rathke cleft cyst, hypophysitis and hypothalamitis during the transition age from childhood to adulthood. In the present review, we provide an overview of the principal parasellar lesions occurring in the transition age. Symptoms are usually a result of the mass effect of the lesions on nearby structures, as well as anterior pituitary deficits. Diabetes insipidus occurs frequently in these patients. In this age group, pubertal developmental disorders may be more evident compared to other stages of life. Parasellar lesions in the transition age mostly include neoplastic lesions such as germinomas, hamartomas, optic gliomas, craniopharyngiomas Langerhans cell histiocytosis and chordomas, and rarely inflammatory lesions (hypophysitis, hypothalamitis). There are limited data on the management of parasellar lesions in the transition age. Endocrine evaluation is crucial for identifying conditions that require hormonal treatment so that they can be treated early to improve the quality of life of the individual patient in this complex age range. The clinical approach to parasellar lesions involves a multidisciplinary effort.

Diagnostic Capability of Cerebrospinal Fluid-Placental Alkaline Phosphatase Value in Intracranial Germ Cell Tumor

OBJECTIVE

Most types of intracranial germ cell tumors (IGCTs) are sensitive to chemoradiation. However, biopsy specimens are usually small and thus cannot be used for obtaining an accurate pathological diagnosis. Recently, the cerebrospinal fluid (CSF) placental alkaline phosphatase (PLAP) value has been considered a new biomarker of IGCTs. The present study aimed to evaluate the discriminatory characteristics of the CSF-PLAP value upon diagnosis and at the time of recurrence in patients with IGCTs.

METHODS

Between 2015 and 2019, this study included 37 patients with tumors located in the intraventricular and/or periventricular region. The CSF-PLAP level was assessed before the patients received any treatment. The PLAP level was evaluated during and after first-line chemoradiotherapy in 7 patients with IGCTs. The CSF-PLAP values were compared according to histological diagnosis, and the correlation between these values and radiographical features was assessed. The CSF-PLAP values of 6 patients with IGCTs with suspected recurrence were evaluated based on neuroimaging findings.

RESULTS

The CSF-PLAP values were significantly higher in patients with IGCTs than in those with other types of brain tumor (n = 19 vs. 18; median: 359.0 vs. <8.0 pg/mL). The specificity and sensitivity were 88 and 95%, respectively, with a cutoff value of 8.0 pg/mL. In patients with IGCT, the CSF-PLAP value was higher in patients with germinoma than in those with nongerminomatous germ cell tumors (n = 12 vs. 7; median: 415.0 vs. 359.0 pg/mL). Regarding the time course, the CSF-PLAP value decreased to below the detection limit after the reception of first-line chemoradiotherapy in all 7 patients. A significant correlation was observed between the initial CSF-PLAP value and the tumor reduction volume after receiving first-line chemoradiotherapy (p < 0.0003, R2 = 0.6165, logY = 1.202logX - 1.727). Among the patients with suspected IGCT recurrence (n = 6), the CSF-PLAP value was high in patients with recurrence (n = 3; median: 259.0 pg/mL), and that in patients (n = 3) without recurrence was below the lower detection limit.

CONCLUSIONS

The CSF-PLAP level is a useful biomarker during the initial diagnosis of IGCTs and at the time of recurrence. It may be associated with the volume of germinomatous components of tumors.

Induction Chemotherapy Reduces Radiation Therapy Dose and Volume in the Treatment of Intracranial Germinoma: Results of the SMC-G13 Trial

PURPOSE

We performed a prospective single-arm trial (NCT02782754) to explore the feasibility of reducing radiation therapy (RT) dose when induction chemotherapy is combined in the treatment of intracranial germinoma with beta-human chorionic gonadotropin levels <200 mIU/mL.

METHODS AND MATERIALS

All patients aged 3 to 35 years from November 2012 to June 2018 were eligible for this study. Four cycles of induction chemotherapy were given before RT. Carboplatin/etoposide and cyclophosphamide/etoposide regimens were used in alternation every 3 weeks. A dose of 18 Gy of craniospinal RT for metastatic tumors, whole brain RT for basal ganglia tumors, or otherwise whole ventricular RT followed by 12.6 Gy of boost RT to the primary tumor bed was administered after induction chemotherapy. The primary endpoint of this study was progression-free survival.

RESULTS

A total of 41 consecutive patients were enrolled (location: suprasellar in 12, pineal in 12, both suprasellar and pineal in 11, and basal ganglia in 6 patients). Eleven patients had leptomeningeal seeding. Toxicity during chemotherapy was mild, except for bone marrow suppression. Tumor status after induction chemotherapy was complete response in 33 patients and partial response in 8. All but 2 patients completed the scheduled treatment. All patients but 1 remained event free during a median follow-up of 3.4 (range, 0.3-7.0) years from diagnosis. The 1 patient experienced relapse and died of tumor bleeding. Late effects were not significant except for neuroendocrine dysfunction already present at diagnosis. Vertical growth and cognitive function were not significantly disturbed by treatment.

CONCLUSIONS

This study showed the feasibility of reducing RT dose/volume with induction chemotherapy in pathologically pure germinoma with elevated beta-human chorionic gonadotropin levels up to 200 mIU/mL.

Comparison on epidemiology, tumor location, histology, and prognosis of intracranial germ cell tumors between Mayo Clinic and Japanese consortium cohorts

OBJECTIVE

Central nervous system (CNS) germ cell tumors (GCTs) are rare malignant neoplasms that arise predominantly in adolescents and young adults. CNS GCTs demonstrate characteristic trends in national associations, with implications for both tumor incidence and genetics. Although the incidence of CNS GCTs is markedly higher in East Asia than Western countries, direct comparative analyses between these CNS GCT populations are limited.

METHODS

In Japan, to facilitate the genomic analyses of CNS GCTs, the Intracranial Germ Cell Tumor Genome Analysis Consortium was established in 2011, and more than 200 cases of GCTs are available for both tumor tissue and clinical data, which is organized by the National Cancer Center (NCC) Japan. At the Mayo Clinic, there have been 98 cases of intracranial GCTs treated by the Department of Neurologic Surgery since 1988. In this paper, the authors compared the epidemiology, clinical presentation including location and histology, and prognosis between cases treated in the US and Japan.

RESULTS

There was no significant difference in age and sex distributions between the databases. However, there was a significant difference in the tumor locations; specifically, the frequency of basal ganglia was higher in the NCC database compared with the Mayo Clinic (8.4% vs 0%, p = 0.008), and bifocal location (neurohypophysis and pineal gland) was higher at the Mayo Clinic than at the NCC (18.8% vs 5.8%, p = 0.002). There was no difference in histological subdivisions between the databases. There was no difference in progression-free survival (PFS) and overall survival (OS) of germinoma cases and OS of nongerminomatous GCT (NGGCT) cases treated with chemotherapy and radiation therapy covering whole ventricles. However, PFS of NGGCTs differed significantly, and was better in the NCC cohorts (p = 0.04).

CONCLUSIONS

There appears to be a differential distribution of GCTs by neuroanatomical location between major geographic and national groups. Further study is warranted to better characterize any underlying genomic, epigenetic, or environmental factors that may be driving the phenotypic differences.

Central Nervous System Germ Cell Tumors: A Review of the Literature

Central nervous system germ cell tumors are rare intracranial tumors that mainly occur in pediatrics with substantial variation in the incidence among different regions and genders. Histologically, central nervous system germ cell tumors can be divided into germinomas and nongerminomatous germ cell tumors. The molecular pathology of central nervous system germ cell tumors, particularly germinomas, is mainly based on the presence of isochromosome 12p, gain-of-function of the KIT gene, and a globally low DNA methylation profile. Diagnoses and differential diagnoses are conducted through imaging, tumor marker detection, surgical biopsy, and cerebrospinal fluid cytology. Germinomas are often treated via whole-ventricular radiotherapy or neoadjuvant chemotherapy combined with reduced-dose whole-ventricular radiotherapy, whereas nongerminomatous germ cell tumors are mainly treated with chemotherapy, surgical resection, and radiotherapy (individually or in combination), depending on tumor composition. Because the main population of patients is pediatric, extending overall survival and reducing treatment side effects should be the main goals of future studies.

Pitfalls of Neuroendoscopic Biopsy of Intraventricular Germ Cell Tumors

OBJECTIVE

A neuroendoscopic biopsy has become common for the diagnosis of ventricular tumors. However, its utility in patients with germ cell tumors (GCTs) has not been well discussed. We examined the usefulness and pitfalls of neuroendoscopic biopsies of intraventricular GCTs at a single institution.

METHODS

We retrospectively studied 21 consecutive patients diagnosed with GCTs by a neuroendoscopic biopsy of the ventricular region via the lateral ventricle. We examined the localization of tumors, histologic diagnoses using biopsies, surgical complications, and consistency of the diagnosis at the latest follow-up.

RESULTS

Tumor specimens were obtained from a pineal lesion (n = 20), neurohypophysial lesion (n = 5), and lateral ventricular wall lesion (n = 2). In 5 patients, the specimens were obtained from multiple areas. The initial diagnoses were pure germinoma (n = 16), immature teratoma (n = 1), yolk sac tumor (n = 1), and mixed GCT (n = 3). Six of 21 patients needed a second transcranial removal of enhanced residual lesions in the course of the treatment. A discrepancy in the histologic diagnosis between 2 surgeries occurred in 3 patients: All 3 patients had a new diagnosis of teratoma component following transcranial surgery. No postoperative mortality or permanent morbidity related to the neuroendoscopic procedures was noted.

CONCLUSION

Neuroendoscopic biopsies are safe and useful for obtaining reliable histologic diagnoses in the management of GCTs. However, for GCTs with mixed histology, biopsies are susceptible to diagnostic errors, especially missing detecting a component of teratoma.

Hematogenous extraneural metastasis of the germinomatous component of a pineal mixed germ cell tumor

A 23-year-old man presented with a mass in the pineal region and obstructive hydrocephalus. A neuroendoscopic biopsy for the lesion, ventriculoperitoneal (VP) shunting, and focal irradiation were conducted as initial treatment. Histological diagnosis of the biopsy specimen was germinoma. He underwent further irradiation and two tumor resections. Histological diagnosis was mature teratoma without a germinomatous component. After serial treatments, the intracranial lesion was controlled. However, 14 months after presentation, extraneural lesions were confirmed in the posterior mediastinum and retroperitoneal space. The biopsy specimen of the retroperitoneal space lesion was histologically diagnosed as germinoma. Although chemotherapy with cisplatin and etoposide was undertaken, extraneural lesions ware uncontrollable and he died. At autopsy, extraneural lesions were confirmed in the posterior mediastinum, retroperitoneal space, and right lung. Histological diagnosis of extraneural lesions was germinoma. This case was considered to be a pineal mixed germ cell tumor mainly consisting of germinoma and mature teratoma, which caused hematogenous metastasis of the germinoma component. Systemic chemotherapy and irradiation for primary lesions as an initial treatment is important to cure the primary lesion and prevent extraneural metastasis.

Descriptive epidemiology of central nervous system germ cell tumors: nonpineal analysis

Central nervous system (CNS) germ cell tumors (GCT) have not been epidemiologically well described. Our study describes 2 population-based series of nonpineal CNS GCT. Data on all primary (malignant and nonmalignant) CNS (ICD-O-3 sites: C70.0-C72.9, C75.1-C75.3) GCT diagnosed between 2000 and 2004 from the Central Brain Tumor Registry of the United States (CBTRUS) and on all malignant GCT diagnosed between 1992 and 2005 from the Surveillance, Epidemiology, and End Results (SEER) were analyzed. Of 234 nonpineal GCT in CBTRUS, the most common site was brain, NOS (31.6%). Males had a greater frequency (59.7%) than females (40.3%). However, by age group, the male-to-female incidence rate ratio (IRR) differed: children (0-14 years) had an IRR of 1.1, young adults (15-29 years) an IRR of 2.3, and adults (aged 30+) an IRR of 1.0. For children and young adults, most tumors were malignant (86.8% and 89.0%, respectively), whereas for adults, more than half were nonmalignant (56.8%). Germinoma was the most frequent diagnosis (61.5%). In SEER, the frequency of malignant GCT in the CNS (2.5%) was greater than that in the mediastinum (2.1%). Of 408 malignant CNS GCT, 216 (52.9%) were nonpineal. The male-to-female IRR was 1.5. Overall relative survival for nonpineal CNS malignant GCT was 85.3% at 2 years, 77.3% at 5 years, and 67.6% at 10 years. Previous studies of GCT that have not stratified by site have suggested greater gender disparity. Nonpineal CNS GCT show no significant gender preference, yet have outcomes similar to pineal GCT.

Correlation of endoscopic biopsy with tumor marker status in primary intracranial germ cell tumors

We retrospectively analyzed the results of eight patients who underwent endoscopic biopsy of a newly diagnosed primary intracranial germ cell tumor (GCT), and correlated tumor pathology with serum and cerebrospinal fluid (CSF) tumor markers and treatment outcome in order to determine the reliability of GCT sampling by this method. A biopsy diagnosis was made in each patient, and the tumor histology correlated with tumor marker measurements for all six patients diagnosed with germinoma and for one with a yolk sac tumor. One biopsy revealed only mature teratoma, an inconclusive result since the patient's serum and CSF tumor markers were elevated. No morbidity was experienced as a result of the operative procedure. Five of six patients diagnosed with germinoma responded completely to radiation therapy and are without evidence of disease, while one suffered a likely germinoma recurrence and was subsequently successfully retreated. We conclude that endoscopic biopsy of marker-negative germ cell tumors is a safe, reliable method of establishing a diagnosis of germinoma. However, endoscopic biopsy may fail to yield an accurate diagnosis in cases of malignant non-germinomatous tumor. We would thus conclude that when primary germ cell tumor is considered, endoscopic tumor biopsy is recommended in patients with a negative biochemical analysis, but not suggested for patients presenting with elevated tumor markers.