Pineal parenchymal tumor of intermediate differentiation: imaging spectrum of an unusual tumor in 11 cases

Pineal Parenchymal Tumors of Intermediate Differentiation: A Case Report and Literature Review

Pineal parenchymal tumors of intermediate differentiation (PPTIDs) account for a significant proportion of pineal tumors and are classified as grade II/III according to the WHO classification. The management of PPTIDs remains controversial because of limited reported cases and the absence of standardized treatment guidelines. We present a case of an eight-year-old male child who presented with vomiting and a sudden squint of the eyes. Imaging revealed a well-defined heterogeneous enhancing lesion in the pineal region with acute hydrocephalus. The patient underwent surgical resection, and the tumor was diagnosed as PPTID. Local recurrence occurred 10 months later, requiring a second surgical intervention and adjuvant radiation therapy. A follow-up showed a regression of the tumor and improvement in symptoms. A literature review of reported PPTID cases revealed variability in clinical presentation, treatment approaches, and outcomes. Headaches were the most common symptom, and surgical resection was the primary treatment modality. Adjuvant therapies such as radiation therapy and chemotherapy were utilized in some cases. Tumor recurrence was observed in several instances, underscoring the need for long-term follow-up. In conclusion, PPTIDs are rare brain tumors with challenging diagnosis and management. Surgical resection remains the mainstay of treatment; however, the optimal approach is uncertain. Standardized reporting and larger studies are necessary to establish guidelines for the management of PPTIDs and improve long-term outcomes.

Radiation therapy for pineal parenchymal tumor of intermediate differentiation: A case series and literature review

Pineal parenchymal tumor of intermediate differentiation (PPTID) is a rare, primary tumor of the pineal gland. Due to its rarity, there is no consensus on optimal therapeutic strategies or standard characterization of the tumor's behavior. Here, we report 2 new cases of PPTID and an extensive review of the literature involving the use and extent of radiation therapy. Patient 1 is a 54-year-old male who presented with PPTID and drop metastases in the spinal cord, received cranial spinal irradiation (CSI), and experienced recurrence 3.5 years after treatment. Stereotactic body radiation therapy (SBRT) helped the patient into remission for 9 months. Patient 2 is a 32-year-old male with a local PPTID at presentation who went on to receive surgical resection followed by focused adjuvant radiation therapy to the pineal tumor bed. He then presented 6 years after treatment with extensive disseminated recurrence and died due to leptomeningeal disease (LMD) about 4 years after recurrence. The available literature on PPTID is limited and reported cases of LMD with ongoing follow-up in PPTID are scarce. Our report adds to the current known PPTID cases, contributing to the information available regarding prognosis and treatment response. Although an optimal therapeutic strategy for PPTID still cannot be determined, data from the literature suggest that utilizing radiation therapy in patients with low-risk disease and gross total resections as well as the use of upfront CSI have the potential to improve patient progression and survival outcomes.

A comprehensive machine-learning model applied to MRI to classify germinomas of the pineal region

BACKGROUND

Pineal region tumors (PRTs) are highly histologically heterogeneous. Germinoma is the most common PRT and is treatable with radiotherapy and chemotherapy. A non-invasive system that helps identify germinoma in the pineal region could reduce lab exams and traumatic therapies.

METHODS

In this retrospective study, 122 patients with histologically confirmed PRTs and pre-operative multi-modal MR images were included. Radiomics features were extracted from different ROIs and image sequences separately. A computational framework that combines a few classification and feature selection algorithms were used to predict histology with radiomics features and demographics. We systemically benchmarked performance of models with feature matrices from all possible combinations of ROIs and image sequences. The Area under the ROC Curve (AUC) was then used to evaluate model performance.

RESULTS

Models with demographics and radiomics features outperform radiomics-only or demographics-only models. The best demographical-radiomics model reached the highest AUC of 0.88 (CI95%: 0.81-0.96). Through the comprehensive evaluation of possible sequence combinations in the differential diagnosis of pineal tumor, T1 and T2 emerged as the most informative sequences for the task. There is imbalanced usage of feature classes as we analyze their proportion in all models.

CONCLUSIONS

The demographical-radiomics model can accurately and efficiently identify germinomas in the pineal region. The preference for MRI sequences, radiomics feature classes, features selection and classification algorithms provide a valuable reference for future attempts at developing classifiers on medical images.

Survival and Associated Predictors for Patients with Pineoblastoma or Pineal Parenchymal Tumor of Intermediate Differentiation Older than 3 years: Insights from the National Cancer Database

Background

The management of pineal parenchymal tumors remains controversial.

Methods

The 2004-2017 National Cancer Database was queried for cases (age >3 years) with histologically confirmed pineal parenchymal tumors of intermediate differentiation (PPTID, n = 90) or pineoblastoma (n = 106).

Results

Within the PPTID group, median age was 41 years; 49% were males. Five- and 10-year survival were 83% and 78%, respectively. Adjuvant radiation and chemotherapy were administered in 64% and 17% patients, respectively. The effect of radiation with or without chemotherapy (HR 1.15, P = .81, and HR 1.31, P = .72, respectively), and extent of resection (HR = 1.07, P = .93) was not significant. Within the pineoblastoma group, median age was 25 years; 51% were males. Five- and 10-year survival were 66% and 42%, respectively. Adjuvant radiation and chemotherapy were administered in 72% and 51%, respectively. In multivariable analysis, patients with pineoblastoma who received both radiation and chemotherapy (n = 39) had significantly lower hazard of death (HR 0.35, 95% CI 0.14-0.85, P = .02) compared to those who received radiation alone (n = 20) or no adjuvant treatment (n = 19). Finally, females in the pineoblastoma group were found to have a lower hazard of death compared to males (HR 0.24, 95% CI 0.10-0.58, P = .001); this comparison trended toward statistical significance in the PPTID subgroup (HR 0.40, 95% CI 0.14-1.08, P = .07).

Conclusions

Survival rates were higher in patients with PPTID vs patients with pineoblastoma. Adjuvant chemoradiation was associated with improved survival in pineoblastoma and females had lower hazards of death. Further research should identify specific patient profiles and molecular subgroups more likely to benefit from multimodality therapy.

Neuroimaging of paediatric pineal, sellar and suprasellar tumours: a guide to differential diagnosis

INTRODUCTION

Pineal, sellar and suprasellar tumours in children comprise a wide range of diseases with different biological behaviours and clinical management. Neuroimaging plays a critical role in the diagnosis, treatment planning and follow up of these patients, but imaging interpretation can prove challenging due to the significant overlap in radiological features.

MATERIALS AND METHOD

A review of the literature was performed by undertaking a search of the MEDLINE and EMBASE databases for appropriate MeSH terminology. Identified abstracts were screened for inclusion and articles meeting the objectives of the review were included.

RESULTS AND CONCLUSION

In this article, we review radiological appearances of common and uncommon pineal, sellar and suprasellar tumours occurring in the paediatric population. We discuss the importance of anatomical localization, clinical information and cerebrospinal fluid tumour markers, and propose a practical approach to differential diagnosis. Lastly, we discuss future directions and prospective new imaging strategies to support state-of-the-art patient care.

Pineal parenchymal tumor of intermediate differentiation: a systematic review and contemporary management of 389 cases reported during the last two decades

Pineal parenchymal tumor of intermediate differentiation (PPTID) is a WHO grade II and III tumor arising from pineal parenchymal cells. PPTID is a rare tumor accounting for less than 1% of all primary central nervous system neoplasms. Therefore, reports describing the clinical characteristics and biological features of PPTID are lacking. Moreover, the therapeutic strategy remains controversial. The current study aimed to evaluate treatment results and problems of contemporary therapeutic modalities of PPTID based on its features compared with other pineal parenchymal tumors. A comprehensive systematic literature review of 69 articles was performed, including articles on PPTID (389 patients) and similar tumors. Patient demographics, disease presentation, imaging characteristics, biological features, and current therapeutic options and their results were reviewed. We found that histopathological findings based on current WHO classification are well associated with survival; however, identifying and treating aggressive PPTID cases with uncommon features could be problematic. A molecular and genetic approach may help improve diagnostic accuracy. Therapeutic strategy, especially for grade III and aforementioned uncommon and aggressive tumors, remains controversial. A combination therapy involving maximum tumor resection, chemotherapy, and radiotherapy could be the first line of treatment. However, although challenging, a large prospective study would be required to identify ways to improve the clinical results of PPTID treatment.

Pineal parenchymal tumor of intermediate differentiation: a single-institution experience

Background

Pineal parenchymal tumors are exceedingly rare brain tumors responsible for less than 1% of all adult primary intracranial malignancies in the United States. In this study, we describe the clinicopathologic features, management, and outcomes of patients with pineal parenchymal tumor of intermediate differentiation (PPTID).

Methods

We describe a single-center, multidisciplinary team experience in managing PPTID patients over a 15-year period (January 2000 to January 2015) at The University of Texas MD Anderson Cancer Center (MDACC). Pathology was reviewed by the pathology collaborators (A.G. and G.N.F.) and retrospective chart review was performed for treatment and clinical outcomes.

Results

We identified 17 patients (9 male) with diagnosis of PPTID. Median age at diagnosis of PPTID was 37 years (range, 15-57 years). Follow-up ranged from 0.1 to 162.8 months with 6 reported deaths. Most patients presented with headaches and diplopia. Three patients had neuroaxial dissemination at initial diagnosis, and recurrence of tumor was common (7/16) despite treatment.

Conclusions

No clear prognostic factors were identified in this series. Extension of resection showed a trend toward improved survival. PPTID with neuroaxial dissemination benefits from aggressive initial treatment including craniospinal irradiation and adjuvant chemotherapy, whereas localized disease may be treated traditionally with maximum debulking followed by adjuvant radiotherapy alone. Long-term monitoring is recommended for neurotoxicity and/or late recurrence.

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.

Pineal parenchymal tumour of intermediate differentiation: a rare differential diagnosis of pineal region tumours

Pineal parenchymal tumours of intermediate differentiation are a rare type of pineal parenchymal tumours. As indicated by their name, these tumours fall between pineoblastoma (a malignant pineal parenchymal tumour) and pineocytoma (a benign pineal parenchymal tumour). In this article, we present a case of pineal parenchymal tumour of intermediate differentiation that was successfully treated by resection via the supracerebellar approach. We also discuss the differential consideration based on epidemiological, pathological and radiological findings.

Histopathologic review of pineal parenchymal tumors identifies novel morphologic subtypes and prognostic factors for outcome

BACKGROUND

Pineal parenchymal tumors (PPTs) are rare neoplasms of the central nervous system, and data concerning clinical outcomes are limited. The purpose of this study was to define the clinical behavior of PPT according to current histopathologic criteria and identify prognostic factors to guide therapeutic decisions.

METHODS

Seventy-five patients treated for PPT at a single institution between 1992 and 2015 were retrospectively identified. Forty-five resection specimens were available and re-reviewed. Freedom from progression (FFP) and overall survival (OS) were estimated using the Kaplan-Meier method and compared using log-rank tests.

RESULTS

Median follow-up was 4.1 years. All patients initially underwent surgery; 78% of patients with PPT of intermediate differentiation (PPTID) and all patients with pineoblastoma received adjuvant therapy. Pathologic re-review refined classification in 27% of cases, with the majority of these being adult patients with pineal tumors originally classified as pineoblastomas that more accurately resembled PPTID based on the 2007 WHO classification.

CLASSIFICATION

Our histologic review also identified that PPTIDs can be classified into small-cell and large-cell morphologic subtypes, which have distinct clinical outcomes. Tumor grade, extent of resection, and neuraxis spread were prognostic for FFP. PPTID subtype, extent of resection, and neuraxis spread were prognostic for OS. Genetic analysis of a pineoblastoma case identified somatic mutations of DICER1, ARID1A, and KDM5C genes.

CONCLUSIONS

PPTIDs can be classified into 1 of 2 novel morphologic subtypes that are associated with distinct clinical outcomes. Tumor grade, neuraxis spread, and extent of resection also influence outcome for patients with PPT.

Twenty-seven cases of pineal parenchymal tumours of intermediate differentiation: mitotic count, Ki-67 labelling index and extent of resection predict prognosis

OBJECTIVE

Optimal grading and treatment of pineal parenchymal tumours of intermediate differentiation (PPTID) have not been established due to their rarity. After careful review of more than 500 pineal region tumours treated in our centre, 27 patients with PPTID were identified.

METHODS

Diagnoses were confirmed according to WHO classification and graded as suggested by Jouvet et al. The relationship between the WHO grade, histopathological characters, management and outcome was analysed.

RESULTS

The WHO grade did not demonstrate significant correlation with outcome. Mitotic count and Ki-67 labelling index (LI) were detected as prognostic factors. Stratification of patients by mitotic count and Ki-67 LI correlated significantly with overall survival and progression-free survival. All the patients underwent resection. Gross total resection (GTR) was achieved in 16/27 (59.3%) patients, subtotal resection in 6/27 (22.2%) patients and partial resection in 5/27 (18.5%) patients. Log rank test confirmed GTR correlated with significantly better survival. Adjuvant therapy had a tendency to correlate significantly with progression-free survival. Among the high-risk patients, 6/9 patients with residual tumour received radiotherapy and 50% (3/6) were free of local tumour recurrence. In the other three high-risk patients with residual tumour who did not receive adjuvant therapy, recurrence occurred early and Ki-67 LI predicted prognosis.

CONCLUSIONS

Risk evaluation combining mitotic count and Ki-67 LI predicts prognosis. Surgery is the most efficient management. GTR is related to better prognosis. If GTR is not achieved, adjuvant therapy might delay tumour progression or recurrence, especially in high-risk patients.

Upfront Stereotactic Radiosurgery for Pineal Parenchymal Tumors in Adults

OBJECTIVE

Pineal parenchymal tumors (PPTs) in adults are rare, and knowledge regarding their optimal management and treatment outcome is limited. Herein, we present the clinical results of our series of PPTs other than pineoblastomas managed by stereotactic radiosurgery (SRS) at upfront setting.

METHODS

Between 1997 and 2014, nine consecutive adult patients with the diagnosis of PPTs, either pineocytoma or pineal parenchymal tumor of intermediate differentiation, were treated with SRS. There were 6 men and 3 women. The median age was 39 years (range, 31-53 years). All of the patients presented with symptoms of hydrocephalus. Endoscopic third ventriculostomy and biopsy was done for initial management. After histologic diagnosis, patients were treated with Gamma Knife with the mean dose of 13.3 Gy (n=3) or fractionated Cyberknife with 32 Gy (n=6).

RESULTS

After a mean follow-up of 78.6 months (range, 14-223 months), all patients were alive and all of their tumors were locally controlled except for one instance of cerebrospinal fluid seeding metastasis. On magnetic resonance images, tumor size decreased in all patients, resulting in complete response in 3 patients and partial response in 6. One patient had experienced temporary memory impairment after SRS, which improved spontaneously.

CONCLUSION

SRS is effective and safe for PPTs in adults and can be considered as a useful alternative to surgical resection at upfront setting.

Pineal parenchymal tumours of intermediate differentiation - An evidence-based review of a new pathological entity

Pineal region lesions are uncommon, and pineal parenchymal tumours (PPT) account for 20-30% of tumours in this area of which pineocytomas (PCs) and pineoblastomas (PBs) are more prevalent. In 2007, the World Health Organisation (WHO) reclassified PPT from two subgroups (PC and PB) into four, including pineal parenchymal tumours of intermediate differentiation (PPTID). PPTID have been further divided into low- and high-grade lesions (WHO II and III), but due to their rarity have proven difficult lesions to diagnose and a paucity of literature means their optimal treatment options are a challenge to define. This article is a review of the literature of PPTID highlighting diagnostic criteria, a discussion on the role of surgery and radiotherapy, including treatment paradigms and reported outcomes for these problematic neoplasms.

Diffusion characteristics of pediatric pineal tumors

BACKGROUND

Diffusion weighted imaging (DWI) has been shown to be helpful in characterizing tumor cellularity, and predicting histology. Several works have evaluated this technique for pineal tumors; however studies to date have not focused on pediatric pineal tumors.

OBJECTIVE

We evaluated the diffusion characteristics of pediatric pineal tumors to confirm if patterns seen in studies using mixed pediatric and adult populations remain valid.

MATERIALS AND METHODS

This retrospective study was performed after Institutional Review Board approval. We retrospectively evaluated all patients 18 years of age and younger with pineal tumors from a single institution where preoperative diffusion weighted imaging as well as histologic characterization was available.

RESULTS

Twenty patients (13 male, 7 female) with pineal tumors were identified: seven with pineoblastoma, four with Primitive Neuroectodermal Tumor (PNET), two with other pineal tumors, and seven with germ cell tumors including two germinomas, three teratomas, and one mixed germinoma-teratoma. The mean apparent diffusion coefficient (ADC) values in pineoblastoma (544 ± 65 × 10⁻⁶ mm²/s) and pineoblastoma/PNET (595 ± 144 × 10⁻⁶ mm²/s) was lower than that of the germ cell tumors (1284 ± 334 × 10⁻⁶ mm²/s; p < 0.0001 vs pineoblastoma). One highly cellular germinoma had an ADC value of 694 × 10⁻⁶ mm²/s.

CONCLUSION

ADC values can aid in differentiation of pineoblastoma/PNET from germ cell tumors in a population of children with pineal masses.

Pineal region masses--imaging findings and surgical approaches

The anatomy of the pineal region is complex. Despite advances in surgical techniques since the first reported successful pineal region surgery in the early 20th century, pineal region surgery remains challenging owing to the proximity of deep cerebral veins and dorsal midbrain structures critical for vision. In this article, we review the relevant surgical anatomy of the pineal region and discuss historically important and current surgical approaches. We describe specific imaging features of pineal region masses that may affect surgical planning and review neoplastic and nonneoplastic masses that occur in the pineal region.

Neuroimaging diagnosis of pineal region tumors-quest for pathognomonic finding of germinoma

INTRODUCTION

Our study aimed to elucidate the imaging features for the differentiation of pineal germinoma and other pineal region tumors.

METHODS

Image data sets of computed tomographic (CT) scan and magnetic resonance imaging (MRI) data of 93 pineal region tumors including 33 germinomas, 30 nongerminomatous germ cell tumors (NGGCTs), 20 pineal parenchymal tumors (PPTs), and 10 miscellaneous tumors of pineal region were reviewed. Imaging features on CT and MRI were qualitatively assessed by three readers. To know the reasons for morphological differences between germinomas and NGGCTs, histological investigation was done.

RESULTS

Localized calcification was seen in more than 70 % of germ cells tumors (GCTs: germinomas and NGGCTs) while it was scattered in more than half of PPTs. Cystic components in tumors were most frequent in NGGCTs (62 %). Multiplicity of lesion was restricted to GCTs: 39.4 % in germinoma and 10.0 % in NGGCTs. Thick peritumoral edema was more frequent in germinoma than in NGGCT: 40.6 vs. 14.8 % (p=0.0433, Fisher's test). Bithalamic extension of tumor was seen in 78.8 % of germinomas. It was significantly rare in other groups of tumors (p<0.0001, Fisher's test). The relative collagen amount per unit area was significantly lower in germinoma than in NGGCTs.

CONCLUSION

By paying attention to characteristic features as bithalamic extension, thick peritumoral edema, calcification pattern, multiplicity, and their combination, the preoperative differential diagnosis of pineal germinoma will become more accurate.

Clinicopathologic study of pineal parenchymal tumors of intermediate differentiation

OBJECTIVE

Pineal parenchymal tumors of intermediate differentiation (PPTID) are extremely rare tumor entities, and only limited data are available regarding their pathologic features and biologic behaviors. Because grading criteria of pineal parenchymal tumors (PPTs) have yet to be established, the treatment strategy and prognosis of PPTIDs remain controversial. We describe the clinicopathologic study of six patients with PPTID and compare responses for the treatment and prognosis with cases of pineocytoma (PC) and pineoblastoma (PB). From this analysis, we attempt to clarify the treatment strategy for PPTIDs.

METHODS

This study included 15 patients with PPTs, consisting of 6 PCs, 6 PPTIDs, and 3 PBs. We focused on the 6 patients with PPTIDs. All PPTID cases were treated surgically, and radiotherapy and chemotherapy were administered as adjuvant therapies in some cases. We have earlier reported the histopathologic study (Neuropathology 32:647-653, 2012). Briefly, we examined mitotic figures and necrosis by hematoxylin-eosin staining and immunohistochemical markers such as neuronal markers (synaptophysin, neurofilament (NF), and neuronal nuclear antigen), and an MIB-1 labeling index was determined.

RESULTS

In the PPTID cases, the extent of resection was variable and the recurrence rates among patients varied according to stage and treatment. All PC patients underwent total resection with no recurrence. All PB patients underwent resection and adjuvant therapy with radiotherapy and chemotherapy. There were no recurrences in patients with PC or PB. The results of histopathologic findings have been already reported as mentioned above. Briefly, the results indicated no mitotic figure or necrosis in any of the six cases of PPTID, but those features were observed in PB cases. All cases even including PC and PB were immunopositive for neuronal markers. The MIB-1 labeling index of PPTID was 3.5%, whereas it was 0% in PC and 10.5% in PB.

CONCLUSIONS

Good radiosensitivity of PPTIDs was observed in our series. Because there are cases with discrepancies between images and pathologic findings, it is very difficult to determine the proper treatment strategy for PPTIDs. Proliferative potential was correlated with World Health Organization grade, although the immunoreactivity of neuronal markers did not correlate with the histologic grade.

Utility of Ki67 immunostaining in the grading of pineal parenchymal tumours: a multicentre study

AIMS

Pineal parenchymal tumours (PPTs) are rare neoplasms that are divided into pineocytoma (PC), pineoblastoma (PB) and PPT of intermediate differentiation (PPTID). Factors affecting the survival of patients with PPTs are morphological subtype and histological grading according to mitotic index and neurofilament immunostaining. Grading criteria to distinguish PPTIDs are difficult to define, particularly when using small specimens. The Ki67 labelling index (LI) might be helpful in distinguishing between grade II and III PPTIDs. Our study was performed to assess the predictive value of the Ki67 LI in a large cooperative series of PPTs and to evaluate whether inclusion of this data would improve and refine the World Health Organization classification.

METHODS

A retrospective analysis of 33 PPTs was performed. The histological features of the tumours were reviewed and Ki67 LI scoring was evaluated by immunohistochemistry. Data were correlated with the patients' survival.

RESULTS

The mean Ki67 LI was significantly different for tumour grades (0 in PC, 5.2 ± 0.4 in PPTID grade II, 11.2 ± 2.0 in PPTID grade III, 36.4 ± 6.2 in PB; P < 0.0001). However, there was no statistically significant difference in either overall or disease-free survival evaluated by the Kaplan-Meier method for patients with different grade tumours or Ki67 LI, possibly due to the different clinical management of patients in different centres.

CONCLUSIONS

The Ki67 LI may be a useful additional tool for grading PPTs, more particularly in small tumour samples.

Distinguishing between germinomas and pineal cell tumors on MR imaging

BACKGROUND AND PURPOSE

Tumors of pineal cell origin have different prognosis and treatment than those of germ cell origin. The recent literature suggests that these tumors often look alike. Our study aimed to differentiate between pineal cell tumor and germinoma based on ADC values, the homogeneity of the mass, and MR imaging characteristics.

MATERIALS AND METHODS

We enrolled 20 patients who had pretreatment MR imaging scans with histologic verification of tumors of pineal cell origin and germinomas. The tumors were measured for the ADC values and for homogeneity by the coefficient of variation of ADC values, and T1WI and T2WI signal intensity values.

RESULTS

The 20 subjects (8 females and 12 males) ranged in age from 1.5-64.9 years, with a mean age of 23.9 years (SD 17.7 years). The mean age of those with germinomas was 13.7 years (SD 3.8 years), less than the mean of 29.4 years for those with pineal cell tumors (SD 19.9 years; P = .016). These 2 groups showed no significant difference in coefficients of variation on T1WI, T2WI, and ADC images. However, germinomas showed statistically significant higher ADC values (mean 1590.69 ± 532.96 × 10(-6) mm(2)/s) than pineal cell tumors (mean 883.58 ± 317.48 × 10(-6) mm(2)/s; P = .02). An accuracy of 89.5%, sensitivity of 83.3%, specificity of 92.3%, PPV of 83.3%, and NPV of 92.3% were yielded for an ADC threshold of 1250.00 × 10(-6) mm(2)/s.

CONCLUSIONS

Germinomas showed higher ADC values than the pineal cell tumors (P = .02), and the patients were younger. Otherwise, there were no definitive imaging characteristics that distinguished pineal cell tumors from germinomas.

The new World Health Organization Classification of Central Nervous System Tumors: what can the neuroradiologist really say?

The WHO Classification of Tumors of the Central Nervous System has become the worldwide standard for classifying and grading brain neoplasms. The most recent edition (WHO 2007) introduced a number of significant changes that include both additions and redefinitions or clarifications of existing entities. Eight new neoplasms and 4 new variants were introduced. This article reviews these entities, summarizing both their histology and imaging appearance. Now with more than 3 years of clinical experience following publication of the newest revision, we also ask, "What can the neuroradiologist really say?" Are there imaging findings that could suggest the preoperative diagnosis of a new tumor entity or variant?