Atypical Tumor Research Articles

Low-grade myofibroblastic sarcoma of the levator scapulae muscle: a case report and literature review

BackgroundLow-grade myofibroblastic sarcoma (LGMS) is described as a distinct atypical myofibroblastic tumor often with fibromatosis-like features and predilection for the head and neck, especially the oral cavity and larynx. LGMS arising in the levator scapulae muscle is extremely rare.Case presentationA 69-year-old woman was admitted to our hospital because she noticed a hard mass in her left neck six months prior. Magnetic resonance images (MRI) showed a soft tissue tumor of the left levator scapulae muscle. A core needle biopsy showed cellular fascicles or a storiform growth pattern of spindle-shaped tumor cells with minimally atypia. Immunohistochemistry revealed focally positive for α-smooth muscle actin (α-SMA), negative for S-100, and a low-grade spindle cell sarcoma was suspected. Following a biopsy, the tumor was resected with a wide surgical margin. Immunohistochemical staining was a positive for vimentin and α-SMA and negative for desmin, CD34, nuclear β-catenin, and h-caldesmon. LGMS diagnosis was determined based on the histopathological findings. The patient was alive with no evidence of disease eight years after the surgery.ConclusionsTo the best of our knowledge, this is the first case report of LGMS arising in the levator scapulae muscle. In addition to the case report, 48 reports with 103 LGMS cases are reviewed and discussed. In previous reports of LGMS, there were 43 females and 60 males, with a mean age of 43.0 years (range, 2–75). There were 13 (12.6%) patients aged < 18 years, 67 (65.1%) patients aged 18 to 59 years, and 23 (22.3%) patients aged ≥60 years. The average tumor size was 4.4 cm (range: 0.4–22.0). The commonest sites of LGMS was the tongue. Tumor growth patterns were evaluated in 52 cases, and 44 cases (84.6%) showed infiltrative growth patterns. Local recurrence was 26.7%, and distant metastasis was 4.4%. Because of the locally aggressive feature, it is important to diagnose LGMS with biopsy and to excise the tumor with an adequately wide margin.

Incidental long bone cartilage lesions: is any further imaging workup needed?

To determine the rate of chondrosarcoma in incidentally discovered painless long bone cartilage lesions and to determine if any further imaging is needed. A cartilage lesion was said to be an enchondroma when it had characteristic matrix mineralization and no aggressive features. Search of all imaging reports and tumor board files for keywords enchondroma, cartilage lesion, chondroid, and chondrosarcoma. Retrospective review of medical records and imaging studies from 4.5-year period. Data points collected included patient age, sex, lesion site, size, symptoms, type of imaging, imaging appearance, and length of follow-up. Only patients with no pain were included as enchondroma. Patients with final diagnosis of chondrosarcoma were included for comparison of all features. Only 1/73 (1.4%) patients with an initial incidentally discovered painless lesion was later diagnosed, with new symptoms, as atypical cartilage tumor. Average age was 59.4years. Bones involved were the femur (n = 33), humerus (n = 30), tibia (n = 7), fibula (n = 2), and ulna (n = 1). Average enchondroma size was 3.9cm (range 1.4-11.5). Average follow-up was 47months (range 2-196months). Eleven long bone chondrosarcomas were identified. All chondrosarcoma patients had pain and aggressive imaging findings. Our study reveals that the rate of chondrosarcoma in incidentally found painless chondroid lesions without aggressive features in long bones is low. Imaging follow-up may be needed only in the setting of new symptoms.

Cancerous pericarditis presenting as cardiac tamponade in a 68-year-old man with pancreatic adenocarcinoma: a case report

IntroductionPericardial effusion is a rare complication of pancreatic cancer. We report a case of cardiac tamponade secondary to pancreatic cancer.Case presentationA 68-year-old Japanese man was diagnosed as having pancreatic cancer during surgery and received chemotherapy for 28 months after the diagnosis. He was admitted to the emergency room with severe dyspnea. Echocardiography revealed pericardial effusion with severe hypofunction. Emergency pericardial drainage was performed to maintain hemodynamics, which resulted in the elimination of 450 mL of blood and the maintenance of circulatory dynamics. Cytological examination of the pericardial fluid revealed atypical cells and tumor cells suggesting adenocarcinoma.ConclusionsTo our knowledge, pancreatic cancer complicated with cancerous pericarditis has not been previously documented. This case highlights the extreme severity of pericardial effusion, a sign of progressive disease, secondary to pancreatic cancer. In the case of neoplastic pericardial effusion, an extremely poor prognosis must be considered.

The incidence and diagnostic relevance of pathological fracture in conventional central chondrosarcoma.

To determine the incidence and diagnostic relevance of pathological fracture in patients with conventional central chondrosarcoma (CC-CS). Retrospective review of patients with CC-CS diagnosed between January 2007 and December 2019. Data collected included age, sex, skeletal location and the presence of pathological fracture at presentation. Histological tumour grade based on surgical resection or needle biopsy was classified as atypical cartilaginous tumour (ACT)/grade 1 CS (ACT/Gd1 CS), high-grade CS (HG-CS) and dedifferentiated CS (DD-CS). The presence of pathological fracture was correlated with age, skeletal location and tumour grade. Three hundred seventeen patients were included (177 males and 140 females with mean age 55.8years, range 9-91years). Mean age of patients without pathological fracture was 54.4years and those with pathological fracture 62.9years (p = 0.002). The major long bones were involved in 171 cases, the flat bones in 112 cases, the mobile spine in 7 cases and the small bones of the hands and feet in 27 cases. There were 81 ACT/Gd 1 CS, 168 HGCS and 68 DD-CS. Pathological fracture was evident at presentation in 51 (16.1%) cases, the commonest bones involved being the femur (n = 21; 41.2%), humerus (n = 10; 19.6%) and acetabulum (n = 7; 13.7%). Pathological facture occurred in 7 cases of ACT/Gd 1 CS (13.7%), 23 cases of HGCS (45.1%) and 21 cases of DD-CS (41.2%) (p = 0.001). Following multivariate analysis, both older age and histological grade were independently significant factors. Pathological fracture was seen in 16.1% of patients with CC-CS. Pathological fractures in the femur, humerus and acetabulum very likely indicate higher tumour grade.

Magnetic Resonance Imaging Role in the Differentiation Between Atypical Cartilaginous Tumors and High-Grade Chondrosarcoma: An Updated Systematic Review.

Chondrosarcoma (CS) is a malignant tumor affecting the bones while atypical cartilaginous tumors (ACTs) are chondral tumors with moderate cellularity, mild atypia, and with myxoid changes and mild metastatic ability. Both can have one of the worst prognoses if not identified early enough. Magnetic resonance imaging (MRI) has been one of the modalities to detect such tumors and we aim to determine the common characteristic and features to be seen while screening for CS or ACTs. We conducted a systematic review of the previously published reports that investigated the diagnostic ability of MRI and the reported characteristics that can differentiate between ACTs and high-grade chondrosarcomas (HGCS). A comprehensive relevant database search was performed to include all the relevant studies. Among these studies, seven studies investigated the overall accuracy in the classification of the different chondroma types. Additionally, many studies reported the characteristic findings of each tumor according to the MRI results. These characteristics mainly included trapped fat, bone marrow edema, cortical damage, and soft-tissue expansion. Therefore, further attention should be given to these criteria for better assessment, differentiation, and favorable outcomes. MRI can efficiently identify some of the characteristics of both ACTs and HGCS. However, combining it with other radiological modalities may lead to a better differentiation. The detection of ACTs and HGCS lesions with MRI solely has been doubted before in the literature.

Analysis of Sentinel Node Biopsy and Clinicopathologic Features as Prognostic Factors in Patients With Atypical Melanocytic Tumors.

Atypical melanocytic tumors (AMTs) include a wide spectrum of melanocytic neoplasms that represent a challenge for clinicians due to the lack of a definitive diagnosis and the related uncertainty about their management. This study analyzed clinicopathologic features and sentinel node status as potential prognostic factors in patients with AMTs. Clinicopathologic and follow-up data of 238 children, adolescents, and adults with histologically proved AMTs consecutively treated at 12 European centers from 2000 through 2010 were retrieved from prospectively maintained databases. The binary association between all investigated covariates was studied by evaluating the Spearman correlation coefficients, and the association between progression-free survival and all investigated covariates was evaluated using univariable Cox models. The overall survival and progression-free survival curves were established using the Kaplan-Meier method. Median follow-up was 126 months (interquartile range, 104-157 months). All patients received an initial diagnostic biopsy followed by wide (1 cm) excision. Sentinel node biopsy was performed in 139 patients (58.4%), 37 (26.6%) of whom had sentinel node positivity. There were 4 local recurrences, 43 regional relapses, and 8 distant metastases as first events. Six patients (2.5%) died of disease progression. Five patients who were sentinel node-negative and 3 patients who were sentinel node-positive developed distant metastases. Ten-year overall and progression-free survival rates were 97% (95% CI, 94.9%-99.2%) and 82.2% (95% CI, 77.3%-87.3%), respectively. Age, mitotic rate/mm2, mitoses at the base of the lesion, lymphovascular invasion, and 9p21 loss were factors affecting prognosis in the whole series and the sentinel node biopsy subgroup. Age >20 years, mitotic rate >4/mm2, mitoses at the base of the lesion, lymphovascular invasion, and 9p21 loss proved to be worse prognostic factors in patients with ATMs. Sentinel node status was not a clear prognostic predictor.

Atypical Virchow-Robin Spaces Mimicking Cystic Primary Brain Tumor – Clinical Report and Literature Review

AbstractThe Virchow-Robin spaces (VRSs), which are often incidentally observed in modern structural neuroimaging examinations, are small cystic cavities that usually surround the small arteries and arterioles at the level of basal ganglia, the anterior perforated substance and the thalamic-mesencephalic junction. Typically, they have similar physicochemical characteristics to cerebral spinal fluid (CSF) and there is no contrast enhancement on brain CT and MRI images. Its real meaning is unknown, although some contemporary studies have suggested that it might be related to certain traumatic brain injury or several other central nervous system (CNS) disorders, as degenerative diseases. Occasionally, some wide and atypical VRS may be mistaken for primary cystic brain tumors, especially in the context of large and symptomatic lesions, multiple clustered cysts, cortical lesions and if there is adjacent reactive gliosis. The present paper reports four patients who were affected by atypical VRS mimicking brain tumors that required imaging follow-up or even a biopsy to confirm the diagnosis or to indicate the correct approach. Although it is not so unusual, one of them occurred concomitantly and adjacent to a diffuse glioma (co-deleted 1p19q, WHO-GII).

P27 as a Transcriptional Regulator: New Roles in Development and Cancer.

p27 binds and inhibits cyclin-CDK to arrest the cell cycle. p27 also regulates other processes including cell migration and development independent of its cyclin-dependent kinase (CDK) inhibitory action. p27 is an atypical tumor suppressor-deletion or mutational inactivation of the gene encoding p27, CDKN1B, is rare in human cancers. p27 is rarely fully lost in cancers because it can play both tumor suppressive and oncogenic roles. Until recently, the paradigm was that oncogenic deregulation results from either loss of growth restraint due to excess p27 proteolysis or from an oncogenic gain of function through PI3K-mediated C-terminal p27 phosphorylation, which disrupts the cytoskeleton to increase cell motility and metastasis. In cancers, C-terminal phosphorylation alters p27 protein-protein interactions and shifts p27 from CDK inhibitor to oncogene. Recent data indicate p27 regulates transcription and acts as a transcriptional coregulator of cJun. C-terminal p27 phosphorylation increases p27-cJun recruitment to and action on target genes to drive oncogenic pathways and repress differentiation programs. This review focuses on noncanonical, CDK-independent functions of p27 in migration, invasion, development, and gene expression, with emphasis on how transcriptional regulation by p27 illuminates its actions in cancer. A better understanding of how p27-associated transcriptional complexes are regulated might identify new therapeutic targets at the interface between differentiation and growth control.

The importance of MRI review following the diagnosis of atypical cartilaginous tumour using image-guided needle biopsy.

To evaluate the role of pre-biopsy MRI for management planning in patients with atypical cartilaginous tumours (ACT) diagnosed on image-guided core needle biopsy (IGCNB). Retrospective review of patients diagnosed with ACT of the appendicular skeleton based on IGCNB who subsequently underwent surgical curettage or resection. Data collected included age, sex, skeletal location and surgical histology classified as ACT, high-grade chondrosarcoma (HG-CS) and dedifferentiated chondrosarcoma (DD-CS). Pre-biopsy MRI studies were reviewed independently by 2 radiologists blinded to surgical histology results and graded as ACT, HG-CS and DD-CS based on MRI features. The study included 24 males and 28 females (mean age 42.1years; range 9-76years). One patient had 2 lesions treated, making a total of 53 lesions. Tumours were located in the femur in 21 cases, humerus in 17, tibia in 9, radius in 4 and ulna and fibula in 1 each. Surgical histology was ACT in 41 cases, HG-CS in 10 and DD-CS in 2, indicating mismatch between IGCNB and surgical histology in 12/53 cases (22.6%). Predicted MRI grade for the 2 readers was ACT in 39 cases each, HG-CS in 13 and 14 cases and DD-CS in 1 and 0 cases. Sensitivity, specificity and accuracy of MRI for predicting HG-CS/DD-CS were 91%, 93% and 92%, respectively. Inter-observer correlation was very good (kappa = 0.94). Review of MRI findings in patients with ACT diagnosed on IGCNB is vital for identifying patients with a HG-CS/DD-CS and is recommended when planning surgical management or considering repeat IGCNB.

Characterization and comparison of genomic profiles between primary cancer cell lines and parent atypical meningioma tumors

BackgroundMeningiomas are the second most common primary tumors of the central nervous system. However, there is a paucity of data on meningioma biology due to the lack of suitable preclinical in vitro and in vivo models. In this study, we report the establishment and characterization of patient-derived, spontaneously immortalized cancer cell lines derived from World Health Organization (WHO) grade I and atypical WHO grade II meningiomas.MethodsWe evaluated high-resolution 3T MRI neuroimaging findings in meningioma patients which were followed by histological analysis. RT-qPCR and immunostaining analyses were performed to determine the expression levels of meningioma-related factors. Additionally, flow cytometry and sorting assays were conducted to investigate and isolate the CD133 and CD44 positive cells from primary atypical meningioma cells. Further, we compared the gene expression profiles of meningiomas and cell lines derived from them by performing whole-exome sequencing of the blood and tumor samples from the patients, and the primary cancer cell lines established from the meningioma tumor.ResultsOur results were consistent with earlier studies that reported mutations in NF2, SMO, and AKT1 genes in atypical meningiomas, and we also observed mutations in MYBL2, a gene that was recently discovered. Significantly, the genomic signature was consistent between the atypical meningioma cancer cell lines and the tumor and blood samples from the patient.ConclusionOur results lead us to conclude that established meningioma cell lines with a genomic signature identical to tumors might be a valuable tool for understanding meningioma tumor biology, and for screening therapeutic agents to treat recurrent meningiomas.

Risk factors of embolism for the cardiac myxoma patients: a systematic review and metanalysis

BackgroundThe risk factors contributing to embolism in cardiac myxoma (CM) are yet controversial. This systematic review and meta-analysis aimed to clarify the risk factors of embolism for the CM patients.MethodsPubMed, Embase, Cochrane library, Web of Science, China National Knowledge Infrastructure, Wan Fang, and Wei Pu databases were searched from inception to June 2019. Statistical analysis was conducted using Stata version 14.0. The pooled odds ratio or mean difference with 95% confidence interval was estimated for each risk factor.ResultsHerein, 12 studies, encompassing 1814 patients, were included. The pooled results suggested that New York Heart Association (NYHA) class I/II (P < 0.01), hypertension (P = 0.03), irregular tumor surface (P < 0.01), tumor in atypical location (P = 0.01), narrow base of tumor (P < 0.01), and increased fibrinogen (FIB) (P < 0.01) are significant risk factors of embolism in CM patients. However, sex, age, body mass index, smoking, left ventricular ejection fraction, diabetes, hyperlipidemia, atrial fibrillation, valvular heart disease, coronary heart disease, tumor size, platelet count, white blood cells, and hemoglobin were not associated with embolism (all P > 0.05).ConclusionsNYHA class (I/II), hypertension, irregular tumor surface, atypical tumor location, the narrow base of tumor, and increased FIB were significant risk factors of embolism in CM patients. For CM patients with these factors, early surgery might be beneficial to prevent embolism.

Does 68Ga-DOTA-NOC-PET/CT impact staging and therapeutic decision making in pulmonary carcinoid tumors?

Purpose of this study was to assess the utility of Ga-DOTA-NOC-PET/computed tomography (CT) (Ga-NOC-PET) in tumor detection, pathological differentiation and baseline staging of pulmonary carcinoids as well as to study its impact on therapeutic decision making. Patients who underwent a Ga-NOC-PET for initial evaluation of bronchopulmonary carcinoid tumors from August 2014 to December 2019 were included. Detection rate of Ga-NOC-PET for the primary lesion was calculated by visual estimation of tracer uptake as per Krenning score. SUVmax of typical and atypical carcinoid tumors was measured and difference compared using nonparametric statistical tests. Proportion of patients with distant metastases was also calculated and its impact on intended treatment was assessed. Imaging, histopathology and treatment details of 119 patients were available for analysis. Majority of tumors had an endobronchial location (74.7%) and showed histopathologic features of typical carcinoid (82.3%). Ga-NOC-PET showed a detection rate/sensitivity of 92.4%. Oncocytic variant on histopathology and smaller tumor size accounted for majority of negative results. Typical carcinoids showed significantly higher SUVmax than atypical tumors (median SUVmax 38.4 vs. 15.7, P = 0.002). Metastases to distant sites outside the thorax were seen in 14 patients (11.7%), primarily in liver and bones changing the intent of treatment from surgery to systemic therapy. Ga-NOC-PET detects asymptomatic distant metastatic disease in a sizeable number of patients (11.7%) with pulmonary carcinoid and thus contribute to clinical management by precluding futile surgeries. It shows a high sensitivity for tumor detection and can help differentiate between typical and atypical carcinoid variants by virtue of their variable tracer uptake. PET/CT using Ga-labeled DOTA peptides should be an integral part of diagnostic workup of patients with lung carcinoid.

Pathology data set for reporting parathyroid carcinoma and atypical parathyroid neoplasm: recommendations from the International Collaboration on Cancer Reporting

Standardized pathologic reporting for cancers improves patient care and prognostic determination. However, access in many countries is limited. To address this issue, the International Collaboration on Cancer Reporting (ICCR), a not-for-profit organization, has the mission to develop and disseminate standardized data sets for global use. Within endocrine organs, the parathyroid gland has rarely been included in formal pathologic data sets. Utilizing an expert international panel of eleven members, an evidence-based data set was developed for parathyroid carcinoma and atypical parathyroid neoplasms. This data set consists of sixteen core (required) elements viewed as essential for documentation of these conditions. Characterizing parathyroid carcinomas and atypical neoplasms begins with correlative clinical information, the operative procedure, specimens submitted, and site of the disease. The pathologic features essential to document include parathyroid weight, size, classification, and, when a carcinoma, the tumor grade. Histologic grade of parathyroid carcinoma incorporates other core elements including necrosis, mitotic count, perineural invasion, and lymphovascular invasion. Documenting the extent of disease locally into adjacent organs, regionally, and distally is critical for staging. Pathologic staging is now included as part of the American Joint Committee on Cancer 8th edition and is included in this data set. Ancillary studies should be recorded when performed as noncore elements. Standardized pathologic data sets for endocrine organs including the parathyroid gland are now available through the ICCR website. These essential resources enhance international standardization for documenting these rare tumors for both patient care and future guidelines.

An imaging protocol for the management of central cartilage tumours of the proximal fibula

To retrospectively review a series of solitary central cartilage tumours (CCTs) of the proximal fibula and propose an imaging protocol for their management. Over 11 years, 48 patients were identified with a CCT of the proximal fibula. The initial magnetic resonance imaging (MRI) and follow-up imaging were assessed for tumour length, endosteal scalloping, or aggressive/malignant features. Each case was categorised according to the Birmingham Atypical Cartilage Tumour Imaging Protocol (BACTIP). The final diagnosis and outcome were reviewed to establish an appropriate imaging protocol for the management of similar cases in the future. The final diagnosis based on imaging alone or imaging and histopathology was enchondroma in 46 cases (96%) and atypical cartilage tumour (ACT)/low-grade chondrosarcoma in two (4%). Using the BACTIP classification, the majority were type IC (48%) with type IA the second commonest (24%). Of 19 that underwent follow-up MRI, only two revealed any increase in length, neither of which was shown to be malignant. No cases re-presented later with evidence of malignant transformation. There has been a significant increase in the number of CCTs of the proximal fibula referred to Royal Orthopaedic Hospital, Birmingham, over the past decade. This can largely be attributed to the increased use of MRI. The majority were benign with only 4% classified as an ACT. A modified BACTIP, the Fibular Atypical Cartilage Tumour Imaging Protocol (FACTIP) is presented, indicating which cases would benefit from follow-up imaging and which require referral to a specialist orthopaedic oncology service.

Cutaneous leiomyosarcoma /&#x0D; atypical smooth muscle sarcoma

Relevance: Cutaneous leiomyosarcoma is a rare primary&#x0D; dermal neoplasm, accounting for up to 2-3% of all superficial&#x0D; sarcomas. It can occur at any age, most likely between the ages&#x0D; of 50 and 70 years. This tumor has a high recurrence potential&#x0D; in case of insufficiently deep excision. Recurrent tumors are&#x0D; more aggressive and characterized by subsequent metastasis.&#x0D; The purpose of the study was to demonstrate the results&#x0D; of the histopathological examination of a cutaneous leiomyosarcoma / atypical smooth muscle tumor.&#x0D; Results: Cutaneous leiomyosarcoma was represented by&#x0D; spindle-shaped cells with high cellularity located in bundles&#x0D; and growing expansively, surrounded by a capsule. The nuclei&#x0D; of the cells were elongated, hyperchromic. Cells with atypical&#x0D; abnormal nuclei were present in smaller quantities. The mitoses, including atypical, were numerous. IHC staining for SMA,&#x0D; Desmin, H-Caldesmon – diffusely positive on tumor cells. The&#x0D; reaction for S100, Myogenin – negative.&#x0D; Conclusion: A cutaneous leiomyosarcoma can be finally&#x0D; diagnosed only after a pathomorphological examination of&#x0D; the specimen and differential diagnostics using additional research methods.

Cutaneous leiomyosarcoma/&#x0D; atypical smooth muscle sarcoma

Relevance: Cutaneous leiomyosarcoma is a rare primary dermal neoplasm, accounting for up to 2-3% of all superficial&#x0D; sarcomas. It can occur at any age, most likely between the ages of 50 and 70 years. This tumor has a high recurrence potential&#x0D; in case of insufficiently deep excision. Recurrent tumors are more aggressive and characterized by subsequent metastasis.&#x0D; The purpose of the study was to demonstrate the results of the histopathological examination of a cutaneous&#x0D; leiomyosarcoma / atypical smooth muscle tumor.&#x0D; Results: Cutaneous leiomyosarcoma was represented by spindle-shaped cells with high cellularity located in bundles&#x0D; and growing expansively, surrounded by a capsule. The nuclei of the cells were elongated, hyperchromic. Cells with atypical&#x0D; abnormal nuclei were present in smaller quantities. The mitoses, including atypical, were numerous. IHC staining for SMA,&#x0D; Desmin, H-Caldesmon – diffusely positive on tumor cells. The reaction for S100, Myogenin – negative.&#x0D; Conclusion: A cutaneous leiomyosarcoma can be finally diagnosed only after a pathomorphological examination of the&#x0D; specimen and differential diagnostics using additional research methods

Sonographic Imaging of an Atypical Glomus Tumor.

Sonographic Imaging of an Atypical Glomus Tumor.

Radiofrequency Ablation for Atypical Cartilaginous Tumors is safe and effective: analysis of 189 consecutive cases

Chondrosarcoma is the second most commonly diagnosed primary bone tumor in adults (after osteosarcoma)...

Long term follow-up of a large series of stage-II/III atypical proliferative serous ovarian tumors

BackgroundThe aim of this study was to assess prognostic factors and implications on further management in a large series of stage-II or III Atypical Proliferative Serous Tumors (APST) with a long-term follow-up. Patients and methodsPatients with APSTs and peritoneal implants treated in, or referred to, our institution were retrospectively reviewed. Prognostic factors on invasive recurrence, disease-free (DFS) and overall survival (OS) were analyzed. ResultsBetween 1971 and 2017, 212 patients were identified and followed (33 having invasive implants). After a median follow-up of 115 months, 70 recurrences were observed, 28 of them under the form of invasive disease. DFS at 5 years and 10 years was 73% and 62% respectively. The use of a conservative treatment (HR = 5.5[3.33–9.08], p < .0001), the presence of ≥3 peritoneal sites with implants (HR = 1.65[1.01–2.72], p = .045) were unfavorable prognostic factors for DFS. The presence of ≥3 peritoneal sites with implants (HR = 3.02[0.96–9.53], p = .049) and the presence of stromal microinvasion (HR = 3.19[1.12–9.1], p = .022) were unfavorable prognostic factors for OS. Non-conservative surgery (HR = 7[2.35–20.87], p = .0002), invasive implants (HR = 5.37[1.29–22.26], p = .013), and ≥ 3 peritoneal sites with implants (HR = 3.56 [1.11–11.39], p = .024) were identified as predictors of recurrence in the form of an invasive disease. Invasive implants were not associated with DFS (HR = 1.39[0.77–2.51], p = .27), nor OS (HR = 1.76[0.57–5.47], p = .32). ConclusionAfter a long-term follow-up, type of peritoneal implants is no longer a prognostic factor for OS. Implants ≥3 peritoneal sites seem to impact significantly OS and then require a specific follow-up in this subgroup of patients.

Neuroimaging of pediatric infratentorial tumors and the value of diffusion-weighted imaging (DWI) in determining tumor grade.

Diffusion-weighted imaging (DWI) provides information about the cellular density of tumors. This feature is useful in grading and identifying different tumor types. To assess the value of diffusion restriction and apparent diffusion coefficient (ADC) values in differentiating pediatric infratentorial tumors. This was a retrospective review of the magnetic resonance imaging (MRI) of 82 children (age range 1-16 years) with infratentorial tumors. Histopathological grading after surgical excision/biopsy was categorized as low grade (WHO grades I and II) (n = 31; 29 pilocytic astrocytomas, 2 ependymomas) and high grade (WHO grade III and IV) (n = 51; 40 medulloblastomas, 8 anaplastic ependymomas, 1 anaplastic astrocytoma, 2 atypical rhabdoid teratoid tumors [ATRT]). MRI features and ADC values were compared among tumor types and grades using a two-tailed t test, Mann-Whitney U test for continuous data and Chi-square test for categorical variables. Diffusion restriction and low ADC value was a feature of high-grade tumors (P<0.001). The mean ADC values of the low-grade and high-grade tumors were 1.567 × 10-3mm2/s and 0.661 × 10-3mm2/s, respectively. Using 0.9 × 10-3mm2/s as the cut-off value, the sensitivity, specificity, positive and negative predictive values for differentiating the grades was 87%, 100%, 100%, and 81.8%, respectively. Significant differences were found between the mean ADC values of the individual tumor types (P<0.05), except between medulloblastoma and ATRT. ADC values and visual assessment of diffusion restriction are useful in tumor grading. The individual tumor types can be identified by an algorithmic approach, using DWI in conjunction with other described MRI features.