Expression of cytokeratin by malignant meningiomas: diagnostic pitfall of cytokeratin to separate malignant meningiomas from metastatic carcinoma

FNA of Meningioma with Rhabdoid Features Presenting as a Lateral Neck Mass

Primary meningioma at extracranial head and neck sites is uncommon. Since fine needle aspiration (FNA) is often the first line diagnostic modality for the evaluation of masses in the head and neck, extracranial meningiomas can create a significant diagnostic pitfall for FNA. We report a case of meningioma with rhabdoid features and BAP1 loss in a 26-year-old woman, presenting as a large neck mass along the carotid sheath. FNA biopsy of the mass demonstrated a highly cellular specimen with clusters of uniform, epithelioid cells with round to ovoid nuclei and moderate nuclear to cytoplasmic ratio. An extensive immunohistochemical panel performed on cell block sections showed that the tumor cells were weakly EMA positive, progesterone receptor was focally positive, and SSTR2A was diffuse and strongly positive. BAP1 immunohistochemistry showed a diffuse loss of expression in the tumor cells. After the cytologic diagnosis of meningioma, a tissue biopsy was performed, and the diagnosis of meningioma with rhabdoid features and BAP1 loss was confirmed. We also perform a literature review of meningioma cases presenting as a neck mass and evaluated by FNA. Our case highlights the significant diagnostic challenges that can be caused by extracranial meningiomas on FNA and the importance of ancillary studies to avoid diagnostic pitfalls.

Establishment of tumor microenvironment-preserving organoid model from patients with intracranial meningioma

BACKGROUND

Although meningioma is the most common primary brain tumor, treatments rely on surgery and radiotherapy, and recurrent meningiomas have no standard therapeutic options due to a lack of clinically relevant research models. Current meningioma cell lines or organoids cannot reflect biological features of patient tumors since they undergo transformation along culture and consist of only tumor cells without microenvironment. We aim to establish patient-derived meningioma organoids (MNOs) preserving diverse cell types representative of the tumor microenvironment.

METHODS

The biological features of MNOs were evaluated using WST, LDH, and collagen-based 3D invasion assays. Cellular identities in MNOs were confirmed by immunohistochemistry (IHC). Genetic alteration profiles of MNOs and their corresponding parental tumors were obtained by whole-exome sequencing.

RESULTS

MNOs were established from four patients with meningioma (two grade 1 and two grade 2) at a 100% succession rate. Exclusion of enzymatic dissociation-reaggregation steps endowed MNOs with original histology and tumor microenvironment. In addition, we used a liquid media culture system instead of embedding samples into Matrigel, resulting in an easy-to-handle, cost-efficient, and time-saving system. MNOs maintained their functionality and morphology after long-term culture (> 9 wk) and repeated cryopreserving-recovery cycles. The similarities between MNOs and their corresponding parental tumors were confirmed by both IHC and whole-exome sequencing. As a representative application, we utilized MNOs in drug screening, and mifepristone, an antagonist of progesterone receptor, showed prominent antitumor efficacy with respect to viability, invasiveness, and protein expression.

CONCLUSION

Taken together, our MNO model overcame limitations of previous meningioma models and showed superior resemblance to parental tumors. Thus, our model could facilitate translational research identifying and selecting drugs for meningioma in the era of precision medicine.

Meningioma: A Pathology Perspective

Meningiomas are dural-based neoplasms that account for ∼37% of all intracranial tumors in the adult population. They can occur anywhere within the central nervous system and have a predilection for females. The World Health Organization classifies meningiomas into 3 grades based on increased risk of recurrence and associated mortality in grade III tumors. Although most tumors are categorized as low-grade, up to ∼15%-20% demonstrate more aggressive behavior. With the long-recognized association with neurofibromatosis type 2 gene mutation, putative driver mutations can be attributed to ∼80% of tumors. Several germline mutations have also been identified in some cases of familial meningiomatosis such as SMARCE1, SUFU, PTEN, and BAP1. Finally, in addition to genetic data, epigenetic alterations, specifically deoxyribonucleic acid methylation, are being increasingly recognized for their prognostic value, potentially adding objectivity to a currently subjective grading scheme.

The identification of H3F3A mutation in giant cell tumour of the clivus and the histological diagnostic algorithm of other clival lesions permit the differential diagnosis in this location

BACKGROUND

Giant Cell Tumour of Bone (GCT) is a locally aggressive primary bone tumour that usually occurs at the epiphyses of the long bones of the appendicular skeleton with a tendency to recurrence. Recurrent somatic H3F3A mutations have been described in 92% of GCT cases. GCTs involving the Clivus are extremely rare lesions and less than 15 cases are described in the literature. They represent a surgery challenge and are easily misdiagnosed. Our aim was to reveal if the genetic bases underlying Clival GCTs were the same of GCTs of long bones to improve the diagnosis and treatment.

METHODS

The targeted somatic sequencing of GCT-related genes (H3F3A, H3F3B, IDH1, IDH2 and ZNF687) was performed on Clival GCT biopsies of two different cases. Histological analyses on the same tissues were used to detect the neoplastic population and its expression profile.

RESULTS

Sanger sequencing revealed that both patients were positive for the p.Gly34Trp mutation in the H3F3A gene. Immunofluorescence assay using monoclonal antibody, specifically detecting the mutant H3.3, highlighted that the mutation only involved the mononuclear cell population and not the multinucleated giant cells. Moreover, immunohistochemistry assay showed that RANKL was highly expressed by the stromal cells within Clival GCT, mimicking what happens in GCT of the long bones. In addition, systematic literature review allowed us to generate a histology-based diagnostic algorithm of the most common clival lesions.

CONCLUSIONS

We conclude that the Clival GCT is genetically defined by somatic mutation in the H3F3A gene, linking it to the GCT of long bones. The similarity with GCTs of long bones let us to hypothesize the utility of Denosumab therapy (already effective for GCTs) in these surgically challenging cases. Moreover, H3F3A genetic screening can be combined to the histological analysis to differentiate GCTs from morphologically similar giant cell-rich sarcomas, while the histological diagnostic algorithm could help the differential diagnosis of other clival lesions.

Tumour stem cells in meningioma: A review

Meningioma is a common intracranial and intraspinal neoplasm accounting for 25-30% of all primary neurological tumours. It is associated with high rates of recurrence especially in higher-grade tumours and lesions located at the skull base. Cancer stem cells are increasingly recognised as the origin of cancer and are attributed to loco-regional recurrence, metastasis and treatment resistance. This review presents the accumulating evidence of the presence of tumour stem cells within meningioma and the stem cell markers being used to characterise this putative primitive population within this common tumour.

Cerebrospinal fluid dissemination of anaplastic intraventricular meningioma: report of a case presenting with progressive brainstem dysfunction and multiple cranial nerve palsies

BACKGROUND

It is extremely rare to see cerebrospinal fluid dissemination of intraventricular meningioma, particularly with the development of acute, progressive brainstem/cerebellar dysfunction with an absence of mass formation in the corresponding anatomical sites.

CASE PRESENTATION

An 81-year-old man was admitted because of double vision, right facial nerve palsy and truncal ataxia. Brain magnetic resonance imaging showed normal findings except for a tumor mass in the left lateral ventricle, which had been noted over 6 months previously. The patient developed hiccups, hyperventilation, and drowsiness, which worsened progressively, and did not respond to corticosteroid or intraventricular immunoglobulin therapy. Cerebrospinal fluid study revealed a mild elevation of protein, and cytology was negative. The patient died and an autopsy was performed. Postmortem investigation disclosed a malignant transformation of benign fibroid meningioma with cerebrospinal fluid dissemination of the malignant cells, diversely involving the surface of brainstem, cerebellum, and spinal cords, secondarily resulting in extensive ischemia in the brain parenchyma by vessel occlusion.

CONCLUSION

If a patient with an intraventricular tumor develops acute, progressive neurological symptoms, the possibility that it is be caused by cerebrospinal fluid dissemination of tumor cells, after malignant transformation, should be considered.

Meningioma with rhabdoid, papillary and clear cell features: case report and review of association of rare meningioma variants

Meningiomas are common central nervous system tumors with a wide range of morphological variants, assigned World Health Organization (WHO) Grades I – III. We report an extremely rare rhabdoid, papillary and clear cell meningioma (WHO Grade III) in a 29-year-old female, who presented with diplopia and headache over a few days, 2 years ago. Magnetic resonance imaging showed a well-circumscribed, lobulated, predominantly solid and contrast-enhancing lesion in the right temporal, parietal and occipital lobes. On routine staining, the tumor did not display classical meningioma features. A wide immunohistochemical panel ruled out metastasis and endorsed the meningothelial nature of the lesion (positivity for epithelial membrane antigen and vimentin). Electron microscopy did not show usual hallmarks of meningioma but was helpful in excluding other tumors. Even though the three variants are associated with aggressive behavior, the patient is currently asymptomatic. The concurrent use of different techniques was essential for diagnosis.

Malignant progression to anaplastic meningioma: Neuropathology, molecular pathology, and experimental models

Meningioma is a common adult intracranial tumor, and while several cases are considered benign, a subset is malignant with biologically aggressive behavior and is refractory to current treatment strategies of combined surgery and radiotherapy. Anaplastic meningiomas are quite aggressive and correspond to a World Health Organization (WHO) Grade III tumor. This highly aggressive phenotype mandates the need for more efficacious therapies. Designing rational therapies for treatment will have its foundation in the biologic understanding of involved genes and molecular pathways in these types of tumors. Anaplastic meningiomas (WHO Grade III) can arise from malignant transformation of lower grade (WHO Grade I/II) tumors, however there is an incomplete understanding of specific genetic drivers of malignant transformation in these tumors. Here, the current understanding of anaplastic meningiomas is reviewed in the context of human neuropathologic specimens and small animal models.

Malignant meningioma with adenocarcinoma-like metaplasia: demonstration of intestinal phenotype

Meningiomas show a diverse histopathologic appearance, often referred to as metaplastic changes; however, adenocarcinoma-like metaplasia is an extremely rare condition. Here, we present a novel case. A dura-based bulky mass located in the right frontotemporal region was identified radiologically in an 83-year-old woman. The tumor, yellow to ash-gray in color, was subtotally removed. Histopathological examination revealed robust adenocarcinoma-like structures within a conventional meningothelial neoplasm. Meningioma elements showed a WHO grade I to III histology. Morphological and immunophenotypic transition between meningothelial and columnar epithelial cells was confirmed on detailed observation. It was of note that the adenocarcinomatous components shared an immunophenotype with intestinal epithelium, expressing CDX2, MUC2 and cytokeratin 20. The present case could be differentiated from secretory meningioma based on distinct cellular atypia, lack of intracytoplasmic lumina and pseudosammoma bodies, and the intact status of the KLF4 gene. In addition, the morphological and immunophenotypic transition excluded the possibility of metastatic carcinoma within meningioma. This is the first reported case of meningioma with adenocarcinoma-like metaplasia harboring an intestinal immunophenotype.

Meningeal tumors histologically mimicking meningioma

A number of meningeal neoplastic lesions may radiologically and clinically simulate meningioma. In the present paper, we review meningeal non-meningothelial tumors which may also mimic different histotypes of meningioma at the histological examination. Awareness that these lesions exist may facilitate their recognition and correct diagnosis, which is of fundamental importance for prognosis and an appropriate therapeutic approach. Histological and immunohistochemical clues for the differential diagnosis are discussed.

Immunohistochemical Detection of CD34, E-cadherin, Claudin-1, Glucose Transporter 1, Laminin, and Protein Gene Product 9.5 in 28 Canine and 8 Feline Meningiomas

The variation in histologic pattern of meningiomas can make their diagnosis challenging. The immunohistochemical profile of 28 canine and 8 feline meningiomas was examined. Tumor types included anaplastic (6 dogs), angiomatoid (1 cat), fibroblastic (3 dogs, 1 cat), meningothelial (1 dog), microcystic (2 dogs), myxoid (3 dogs), psammomatous (4 cats), and transitional (13 dogs, 2 cats). The authors compared the expression of novel markers (CD34, E-cadherin, claudin-1, glucose transporter 1 [GLUT-1], laminin, and protein gene product [PGP] 9.5) with published markers (cytokeratins, glial fibrillary acidic protein [GFAP], progesterone receptor, S100, and vimentin). Neoplastic cells were immunohistochemically positive for vimentin in 100% of the meningiomas; CD34, 94%; GLUT-1, 86%; E-cadherin, 81%; S100, 75%; laminin, 72%; claudin-1, 60%; PGP 9.5, 55%; progesterone receptor, 44%; pancytokeratins, 39%; cytokeratins 8/18, 17%, and GFAP in 9%. Ki67 index did not correlate well with mitotic index. Based on these results and those in the human literature, immunohistochemistry for vimentin, CD34, and E-cadherin is proposed to support a diagnosis of meningioma. Immunohistochemistry for claudin-1, albeit of only moderate to low sensitivity in canine and feline meningiomas, may help to distinguish meningioma from some mesenchymal neoplasms involving the brain and associated structures, such as schwannomas, which in humans express claudin-1 poorly or not at all. Further studies with CD34, E-cadherin, and claudin-1 in canine and feline tumors that may mimic meningiomas are needed to determine the adequacy of this approach.

Primary extracranial meningiomas: an analysis of 146 cases

Primary extracranial meningiomas are rare neoplasms, frequently misdiagnosed, resulting in inappropriate clinical management. To date, a large clinicopathologic study has not been reported. One hundred and forty-six cases diagnosed between 1970 and 1999 were retrieved from the files of the Armed Forces Institute of Pathology. Histologic features were reviewed, immunohistochemistry analysis was performed (n = 85), and patient follow-up was obtained (n = 110). The patients included 74 (50.7%) females and 72 (49.3%) males. Tumors of the skin were much more common in males than females (1.7:1). There was an overall mean age at presentation of 42.4 years, with a range of 0.3-88 years. The overall mean age at presentation was significantly younger for skin primaries (36.2 years) than for ear (50.1 years) and nasal cavity (47.1 years) primaries. Symptoms were in general non-specific and reflected the anatomic site of involvement, affecting the following areas in order of frequency: scalp skin (40.4%), ear and temporal bone (26%), and sinonasal tract (24%). The tumors ranged in size from 0.5 up to 8 cm, with a mean size of 2.3 cm. Histologically, the majority of tumors were meningothelial (77.4%), followed by atypical (7.5%), psammomatous (4.1%) and anaplastic (2.7%). Psammoma bodies were present in 45 tumors (30.8%), and bone invasion in 31 (21.2%) of tumors. The vast majority were WHO Grade I tumors (87.7%), followed by Grade II (9.6%) and Grade III (2.7%) tumors. Immunohistochemically, the tumor cells labeled for EMA (76%; 61/80), S-100 protein (19%; 15/78), CK 7 (22%; 12/55), and while there was ki-67 labeling in 27% (21/78), <3% of cells were positive. The differential diagnosis included a number of mesenchymal and epithelial tumors (paraganglioma, schwannoma, carcinoma, melanoma, neuroendocrine adenoma of the middle ear), depending on the anatomic site of involvement. Treatment and follow-up was available in 110 patients: Biopsy, local excision, or wide excision was employed. Follow-up time ranged from 1 month to 32 years, with an average of 14.5 years. Recurrences were noted in 26 (23.6%) patients, who were further managed by additional surgery. At last follow-up, recurrent disease was persistent in 15 patients (mean, 7.7 years): 13 patients were dead (died with disease) and two were alive; the remaining patients were disease free (alive 60, mean 19.0 years, dead 35, mean 9.6 years). There is no statistically significant difference in 5-year survival rates by site: ear and temporal bone: 83.3%; nasal cavity: 81.8%; scalp skin: 78.5%; other sites: 65.5% (P = 0.155). Meningiomas can present in a wide variety of sites, especially within the head and neck region. They behave as slow-growing neoplasms with a good prognosis, with longest survival associated with younger age, and complete resection. Awareness of this diagnosis in an unexpected location will help to avoid potential difficulties associated with the diagnosis and management of these tumors.

Intracranial meningioma containing metastatic colon carcinoma

Tumour-to-tumour metastasis is a rare pathological entity. Meningioma is the most common intracranial tumour to host metastases, the majority of which arise from breast and lung cancers. We present the first report of a colonic cancer metastasis within an intracranial meningioma.A 76-year-old woman presented with a one month history of partial seizures. Her medical history included resection of an adenocarcinoma of the descending colon followed by adjuvant chemotherapy 1 year before our evaluation. Magnetic resonance imaging revealed a homogeneously enhancing lesion in the right frontal convexity.A well capsulated tumour attached to the frontal dura was surgically removed. The pathological examination demonstrated a mixture of fibrous meningioma and colloid adenocarcinoma. Possible explanations for the development of a cohesive chimeric mass of composite pathology are investigated.