Rhabdoid transformation of tumor cells in meningiomas: a histologic indication of increased proliferative activity: report of four cases

Pediatric rhabdoid meningioma: a morphological, immunohistochemical, ultrastructural and molecular case study

Rhabdoid meningioma is an uncommon meningioma variant categorized as WHO grade III. The majority of cases occur in adulthood. Herein, we describe a right fronto-temporal rhabdoid meningioma affecting a 3-year-old boy. The lesion measured approximately 4 cm in diameter and incorporated the ipsilateral middle cerebral artery. Sub-total surgical excision of the mass was performed. Histologically, the tumor was mainly composed of globoid plump cells with inclusion-like eosinophilic cytoplasm, peripheral nuclei, prominent nucleoli and occasional intra-nuclear cytoplasmic pseudo-inclusion. The cells appeared in many areas loosely arranged and focally disclosed a papillary architecture. At immunohistochemistry, the tumor cells were EMA, vimentin, HHF35, PgR, INI-1 and p53 positive. The proliferative index (Mib-1) was 15% in the most positive areas. Ultrastructurally, tumoral cells showed an abundant cytoplasm, which was filled with numerous intermediate filaments. Desmosomal junctions were seen. RT-PCR revealed the presence of NF2 gene expression. Molecular study did not indicate alterations of the INI-1 gene, whereas it showed the presence of Pro72Arg in exon 4 at heterozygous state in the TP53 gene. Morphologic features along with immunohistochemical, ultrastructural and molecular results were consistent with the diagnosis of rhabdoid meningioma. The patient was treated with chemotherapy. The lesion remained stable after 33 months of follow-up. Rhabdoid meningiomas rarely occur in children. Owing to its rarity, each new case should be recorded to produce a better clinical, pathological, molecular, prognostic and therapeutic characterization of this lesion.

Rhabdoid papillary meningioma: a clinicopathologic case series study

World Health Organization (WHO) grade III meningiomas are subclassified on the basis of their architectural pattern into papillary and rhabdoid subtypes. Some meningiomas even combine papillary architecture with rhabdoid cytology. Additionally, they always show malignant histological features, follow an aggressive clinical course and tend to spread through the CSF after frequent local recurrence. We render the first series of rhabdoid papillary meningioma with review of the literature to further elucidate its biological behavior. From six patients (three male, three female), nine specimens of rhabdoid papillary meningioma were obtained between 1994 and 2010. Correlations of histologic parameters, immunohistochemical study, and clinical features were assessed. The mean age of patients was 44.7 years at their first operation. The mean postoperative follow-up period was 63.2 months. Five patients experienced tumor recurrence, and one of them died from the disease after diffuse leptomeningeal dissemination. The mean time to first recurrence was 28 months. Only one patient was free of tumoral recurrence after an 8-year follow-up. Immunohistochemically, all tumors were positive for vimentin and epithelial membrane antigen. MIB-1 labeling indices were higher following tumor recurrence. The present study expands the clinicopathologic horizon of rhabdoid papillary meningioma and suggests that it will behave aggressively based on its histology and concomitant features of atypia or malignancy or high MIB-1 labeling indices. Close follow-up and aggressive treatments of these tumors are warranted.

Papillary meningioma with leptomeningeal seeding

A 43-year-old male presenting with headache and dizziness underwent craniotomy and gross total resection of an extraaxial tumor was achieved via left occipital interhemispheric approach. The tumor was diagnosed as papillary meningioma arising from the left falcotentorium with such pathologic characteristics of bronchoalveolar adenocarcinoma. At postoperative day 40, he developed generalized tonic clonic seizure and then progressed to a status epilepticus pattern. Brain magnetic resonance imaging showed irregular leptomeningeal enhancement with a significant peritumoral area. Through a cerebrospinal fluid (CSF) study, we identified the meningioma cells of the papillary type from the CSF. At the postoperative day 60, he fell into semicomatose state, and the computed tomography imaging showed low density on both cerebral hemispheres, except the basal ganglia and cerebellum, with overall brain swelling and an increased intracranial pressure. He died on the following day. We experienced a rare case of a papillary meningioma with leptomeningeal seeding.

Rhabdoid meningioma: rapid intraoperative diagnosis on squash smears

Rhabdoid morphology in tumors refers to resemblance of the cells to rhabdomyoblasts without true skeletal muscle differentiation. The cytological features include abundant eosinophilic cytoplasm, eccentric nuclei, and intracytoplasmic hyaline inclusions. Besides the rhabdoid morphology, cytoarchitectural features of atypical meningioma (four or more mitoses per 10 high-power fields, high cellularity, sheeting architecture, nuclear atypia, and necrosis) are seen in most cases. A case is presented here to highlight the appearance of rhabdoid cells on intraoperative squash smears, for most accurate treatment and close follow-up, as rhabdoid morphology is related to aggressive behavior and poor outcomes.

Diffuse craniospinal metastases of intraventricular rhabdoid papillary meningioma with glial fibrillary acidic protein expression: a case report

Rhabdoid papillary meningioma is a recently described clinically aggressive variant of meningiomas with a high recurrence rate. Additionally, only one case of intraventricular rhabdoid meningioma has been reported so far. We present a case of a 50-year-old man who developed an intracranial tumor of the left lateral ventricle at the trigone, for which he underwent total tumor resection followed by gamma knife radiosurgery for recurrence of the tumor. The histological diagnosis was rhabdoid papillary meningioma. Five years after surgery, diffuse craniospinal leptomeningeal metastases developed and subtotal removal of the spinal tumor was performed. The spinal tumor was considered to have metastasized via cerebrospinal fluid (CSF) in view of its histological features that were identical to those of the primary tumor. Immunohistochemistry revealed the unusual cytoplasmic expression of glial fibrillary acidic protein (GFAP) of tumor cells. To our knowledge, this is the first reported case of diffuse craniospinal metastases of intraventricular rhabdoid papillary meningioma with GFAP expression and the second reported case of the rhabdoid subtype amongst intraventricular meningiomas.

Diffusion-weighted MR imaging: diagnosing atypical or malignant meningiomas and detecting tumor dedifferentiation

BACKGROUND AND PURPOSE

Atypical and malignant meningiomas are uncommon tumors with aggressive behavior and higher mortality, morbidity, and recurrence compared with benign tumors. We investigated the utility of diffusion-weighted (DW) MR imaging to differentiate atypical/malignant from benign meningiomas and to detect histologic dedifferentiation to higher tumor grade.

MATERIALS AND METHODS

We retrospectively compared conventional and DW MR images (b-value 1000 s/mm(2)) acquired on a 1.5T clinical scanner between 25 atypical/malignant and 23 benign meningiomas. The optimal cutoff for the absolute apparent diffusion coefficient (ADC) and normalized ADC (NADC) ratio to differentiate between the groups was determined by using receiver operating characteristic (ROC) analysis.

RESULTS

Irregular tumor margins, peritumoral edema, and adjacent bone destruction occurred significantly more often in atypical/malignant than in benign meningiomas. The mean ADC of atypical/malignant meningiomas (0.66 +/- 0.13 x 10(-3) mm(2)/s) was significantly lower compared with benign meningiomas (0.88 +/- 0.08 x 10(-3) mm(2)/s; P < .0001). Mean NADC ratio in the atypical/malignant group (0.91 +/- 0.18) was also significantly lower than the benign group (1.28 +/- 0.11; P < .0001), without overlap between groups. ROC analysis showed that ADC and NADC thresholds of 0.80 x 10(-3) mm(2)/s and 0.99, respectively, had the best accuracy: at the NADC threshold of 0.99, the sensitivity and specificity were 96% and 100%, respectively. Two patients had isointense benign tumors on initial DW MR imaging, and these became hyperintense with the decrease in ADC and NADC below these thresholds when they progressed to atypical and malignant meningiomas on recurrence.

CONCLUSIONS

ADC and NADC ratios in atypical/malignant meningiomas are significantly lower than in benign tumors. Decrease in ADC and NADC on follow-up imaging may suggest dedifferentiation to higher tumor grade.

Rhabdoid and papillary meningioma with leptomeningeal dissemination

Rhabdoid meningioma is a rare variant of meningioma classified as grade III under the new World Health Organization (WHO) classification of brain tumors. Although this tumor is known for its aggressive behavior, dissemination into cerebral spinal fluid (CSF) is extremely rare. We report here a case of rhabdoid meningioma in a young man, operated on twice previously, who presented with multiple CSF areas of seeding in the brain and spinal cord. The imaging findings for this tumor, including diffusion and perfusion MR sequences, are highlighted. This particular histological subtype of meningioma has a poor prognosis and must be treated aggressively.

Rhabdoid meningioma: clinical features and MR imaging findings in 15 patients

BACKGROUND AND PURPOSE

Rhabdoid meningioma (RM) is a recently described variant of malignant meningioma, with radiologic features currently not well characterized in the medical literature. The purpose of this study was to describe and characterize clinical features and imaging findings associated with RM.

MATERIALS AND METHODS

CT (n = 8) and MR (n = 15) images of 15 patients (4 men and 11 women; mean age, 52 years; range, 22-75 years) with 16 pathologically proved RMs along with associated clinical records were retrospectively reviewed. All of the patients underwent surgical resection and had additional radiation therapy except for 1 patient. After surgery, the patients had follow-up brain MR imaging to evaluate for tumor recurrence.

RESULTS

Nine lesions (56%) were located in the cerebral convexity, and 4 lesions (25%) were located in the parasagittal areas. The tumors were isointense (n = 15) to gray matter on T1-weighted images, whereas they were hyperintense (n = 14) on T2-weighted images. On gadolinium-enhanced T1-weighted images, homogeneous enhancement was seen in 10 lesions, and heterogeneous enhancement was seen in 6 lesions that had cysts. Cystic components were noted in 6 lesions (38%). Severe peritumoral edema was seen in 12 lesions (75%). Nine lesions (56%) had hyperostosis, and 5 of them also had bone destruction. Among the 8 cases with initial CT scans, only 1 had amorphous calcifications (13%). There was only 1 recurrence of RM found during the follow-up period after surgical resection.

CONCLUSION

RMs tend to have prominent peritumoral edema, cystic components, and bone involvement.

Rhabdoid choroid plexus carcinoma: a rare histological type

Primary central nervous system atypical teratoid/rhabdoid tumors mostly occur during early childhood and are almost invariably fatal. These tumors show similar histological and radiological features to primitive neuroectodermal tumor, meduloblastoma and choroid plexus carcinoma, but present different biological behaviors. We present the case of an 18 year-old man who presented headache, vomiting and ataxia. CT-scan and MRI revealed a posterior fossa tumor. A gross total resection was performed. An intraoperative study showed papillary-like tumors with large cells and mitotic features. Histological examination showed two different main growth patterns: solid sheets of undifferentiated polygonal cells with papillary features and rhabdoid cells. Immunohistochemically, these rhabdoid cells were positive for vimentin, epithelial membrane antigen, smooth-muscle actin, cytokeratin, S-100 protein, and glial fibrillary acidic protein. Electro-microscopically, the typical rhabdoid cells contained whorled bundles of intermediate filaments in their cytoplasm. A rhabdoid tumor is a clinicalpathological entity and emphasizes the necessity to distinguish this unique tumor from other pediatric central nervous system neoplasms. Cytopathological features, immunohistochemistry and electro-microscopy differential diagnoses are discussed.

Intraventricular rhabdoid meningioma

Rhabdoid meningioma is a rare variant of meningioma, often found in tumour recurrences. We report a 55-year-old woman with a history of intraventricular fibroblastic meningioma, who developed headache and tinnitus 5 years after complete resection of the initial tumour. Imaging confirmed a recurrent tumour in the intraventricular location. Histological analysis revealed rhabdoid meningioma. We reviewed the literature and were unable to find any previously reported cases of intraventricular rhabdoid meningioma.

Atypical teratoid/rhabdoid tumor arising in the setting of a pleomorphic xanthoastrocytoma

We present a case of a 23-year-old man with a tumor containing glial and rhabdoid elements where the former had features of a pleomorphic xanthoastrocytoma (PXA) and the latter had the immunophenotype and genetic profile of an atypical rhabdoid/teratoid tumor. The patient presented with a short history of raised intracranial pressure with rapid deterioration in sensorium. He had a poor outcome despite surgery and radiotherapy. We report this case because of its unusual presentation in adulthood and its occurrence in association with a PXA. We speculate that the PXA was a quiescent tumor and that the secondary genetic alterations, including inactivation of the INI1 gene led to clinical progression.

Histological classification and molecular genetics of meningiomas

Meningiomas account for up to 30% of all primary intracranial tumours. They are histologically classified according to the World Health Organization (WHO) classification of tumours of the nervous system. Most meningiomas are benign lesions of WHO grade I, whereas some meningioma variants correspond with WHO grades II and III and are associated with a higher risk of recurrence and shorter survival times. Mutations in the NF2 gene and loss of chromosome 22q are the most common genetic alterations associated with the initiation of meningiomas. With increase in tumour grade, additional progression-associated molecular aberrations can be found; however, most of the relevant genes are yet to be identified. High-throughput techniques of global genome and transcriptome analyses and new meningioma models provide increasing insight into meningioma biology and will help to identify common pathogenic pathways that may be targeted by new therapeutic approaches.

Primary rhabdoid tumor of the brain in an adult

Rhabdoid tumor (RT) is an uncommon childhood neoplasm that typically arises within the kidney. It is characterized by an aggressive clinical course. Since its description in 1978, several cases of primary extrarenal RT, including a CNS localization, have been reported. The first case in the CNS was reported in 1985 and was defined as "rhabdoid tumor" initially, and was classified as grade IV in the most recent classification of the World Health Organization under the term of "atypical teratoid/rhabdoid tumor". Nearly 200 cases of atypical teratoid/rhabdoid tumor of the CNS have been reported to date, most of them occurring in childhood. We report a case of primary RT of the brain located in the right frontal lobe with the clinical, radiographic and pathological features presenting at an unusual age. This tumor, which was composed purely of rhabdoid cells with no additional primitive neuroectodermal, epithelial and mesenchymal components, was in a 27-year-old male patient. In conclusion, RT should be considered also in the differential diagnosis of intracerebral neoplasms of adult patients.

Meningeal tumors of childhood and infancy. An update and literature review

Meningeal derived tumors of the first 2 decades of life are often diagnostically challenging due to the wide morphologic spectrum encountered and the rarity of most individual entities. The 2 most common patterns include the dural/leptomeningeal-based mass and neoplastic meningitis. Both primary and secondary meningeal presentations may occur, either early or late in the course of various meningothelial, mesenchymal, embryonal, glial, hematopoietic, histiocytic, melanocytic, and inflammatory tumors. As in other areas of pediatric pathology, there are significant differences between this patient cohort and adults, differences which will be emphasized in this review.

Rhabdoid meningioma: a new subtype of malignant meningioma also apt to occur in children

CASE REPORT

The case of a 14-year-old girl who presented with a 2-week history of raised intracranial pressure is reported. A left frontal extra-axial tumor was totally removed, whose histopathologic diagnosis was rhabdoid meningioma (RM).

DISCUSSION

Rhabdoid meningiomas constitute a special malignant phenotype of meningioma that has been recently included in the WHO classification of tumors of the nervous system. Usually, RMs affect middle-aged and elderly individuals. We report the fourth case of a RM occurring in a child to illustrate that the diagnosis of this tumor subtype, given its prognostic implications, must also be considered in pediatric patients.

Newly defined central nervous system neoplasms

In recent years, numerous new entities or variants of recognized central nervous system tumors have been described in the literature, and the morphologic spectrum of these neoplasms is delineated incompletely. The accurate diagnosis and classification of these lesions is important to ensure that patients receive adequate therapy and prognostic information. The clinicopathologic features and differential diagnosis of 4 new entities, including the chordoid glioma of the third ventricle, cerebellar liponeurocytoma, atypical teratoid/rhabdoid tumor, and papillary glioneuronal tumor, are discussed in this review.

INI1 expression is retained in composite rhabdoid tumors, including rhabdoid meningiomas

Rhabdoid cells are encountered in specific entities, such as malignant rhabdoid tumor and atypical teratoid/rhabdoid tumor, as well as in composite rhabdoid tumors derived secondarily from other tumor types. Although rhabdoid tumors are uniformly aggressive, distinction of the entity from the phenotype remains important for its therapeutic implications. The majority of malignant rhabdoid tumors and atypical teratoid/rhabdoid tumors affect infants and young children, harbor chromosome 22q deletions, and inactivate the INI1/hSNF5/BAF47 tumor suppressor gene on 22q11.2. In contrast, most composite rhabdoid tumors are diagnosed in adults, with FISH detectable 22q losses the exception rather than the rule. However, this assay remains limited since 22q dosages are maintained in 20-30% of malignant rhabdoid tumors and atypical teratoid/rhabdoid tumors. Furthermore, chromosome 22 losses are common in some parent tumor types, particularly meningiomas. The recently developed INI1 antibody shows loss of nuclear expression in malignant rhabdoid tumors and atypical teratoid/rhabdoid tumors, though its status in composite rhabdoid tumors is largely unknown. Therefore, we utilized immunohistochemistry and FISH to study INI1 expression and 22q dosages, respectively, in 40 composite rhabdoid tumors, including 16 meningiomas, 15 carcinomas, three melanomas, two sarcomas, two glioblastomas, and 1 neuroblastoma. Approximately 70% of rhabdoid meningiomas had a 22q deletion, but this was rare in other tumor types. Except for one retroperitoneal leiomyosarcoma, nuclear INI1 expression was retained in all composite rhabdoid tumors, including meningiomas with 22q deletion. Therefore, we conclude that INI1 immunohistochemistry is a relatively simple, sensitive, and specific technique for distinguishing malignant rhabdoid tumor and atypical teratoid/rhabdoid tumor from composite rhabdoid tumor.

June 2004: a male in his late 60s with recurrent extracerebral tumor

June 2004: Over the past year, this man in late-60s had complained about progressive weakness of concentration and memory disturbances, associated with word finding difficulties. MRI examination revealed an extra-axial, parasagittal tumor 3 cm in diameter located in the left frontoparietal region. Five years ago, a meningioma in the same region, with radiographic appearance comparable to the present tumor had been totally removed. The histological picture of the current tumor was dominated by sheets of large rounded pleomorphic tumor cells with abundant eosinophilic cytoplasm and eccentric nuclei (rhabdoid cells). Cytoplasmic inclusions were frequent; occasionally,multinucleatedtumorcellswereseen. Mitoticfigures were absent and the MIB was 3%. Meningothelial lobules were scarce, and regions with fibroblastic appearance were absent. There were no psammoma bodies, necrosis or brain invasion. Moderate immunoreactivity for EMA was found. Additionally, strong cytoplasmic immunoreaction for vimentin within the rhabdoid cells was observed. Review of the previous material showed small islets of rhabdoid cells. Rhabdoid meningioma is an uncommon meningioma variant. It has been suggested that rhabdoid meningiomas are highly aggressive tumors (WHO grade III)and that the rhabdoid phenotype represents a marker of malignant transformation in meningiomas. Histologically, rhabdoid meningiomas usually exhibit signs of anaplasia, a high mitotic activity, and a markedly increased MIB-1 labeling index. Extracranial metastases may occur in the course of the disease. However, not all rhabdoid tumors appear to have anaplastic features (as this case illustrates). Another interesting feature of rhabdoid meningiomas is that in a significant number of cases, the rhabdoid cells appear only at the time of recurrence. Alternatively, as seen in this case, the rhabdoid cells may be already present in the primary meningioma, but not as the predominating histological feature.

Rhabdoid meningioma occurring in an unrelated resection cavity with leptomeningeal carcinomatosis

✓ Rhabdoid meningioma (RM) is a recently described, aggressive variant of meningioma. The authors report a case of RM occurring in the resection cavity of an unrelated neurosurgical procedure, temporal lobectomy for intractable seizures. The patient presented with intractable headache 10 years after the temporal lobectomy. Imaging revealed a dura-based, uniformly enhancing lesion within the resection cavity. She underwent gross-total resection and the findings of the surgical pathological report were consistent with an RM, with a dramatically elevated MIB-1 index of approximately 50%. The patient's clinical course was complicated by severe pain and communicating hydrocephalus secondary to rapid dissemination of malignant cells throughout the CSF pathways. Despite aggressive measures, including tumor resection, ventriculoperitoneal shunt placement, and the initiation of conventional radiation therapy, the ensuing leptomeningeal carcinomatosis proved to be rapidly fatal.

Rhabdoid meningioma: intraoperative diagnosis using smear preparation

Tumors with rhabdoid morphology were first described by Beckwith and Palmer in 1978 as aggressive renal tumors in very young children. Subsequently, rhabdoid tumors and tumors with rhabdoid features have been described in many other organ systems and all tend to have a poor outcome no matter what the histogenesis of the original tumor. Rhabdoid cells are plump, with abundant eosinophilic fibrillary to hyaline cytoplasm and peripheral, vesicular, variably pleomorphic nuclei. Nucleoli are invariably present. While their morphology is well recognized in processed biopsy material, their presence on a smear preparation can be quite startling. A case is presented to highlight the appearance of rhabdoid cells on an intraoperative smear preparation of a rhabdoid meningioma. An accompanying secretory component added to the complex picture.

Rhabdoid meningioma: cytopathologic findings in cerebrospinal fluid

Rhabdoid meningioma is a recently described, rare, WHO Grade III intracranial tumor with an aggressive growth pattern and increased risk of recurrence. We describe the cytopathologic findings on cerebrospinal fluid of one such case in a 26-yr-old female who underwent resection of a left temporo-parietal mass. Cerebrospinal fluid contained abundant malignant cells with a prominent "rhabdoid" phenotype, i.e., large cells, eccentric nuclei, single prominent nucleoli, and dense eosinophilic cytoplasm. Although rhabdoid meningioma has a characteristic cytomorphology, the differential diagnosis of this tumor would involve metastatic adenocarcinoma, metastatic malignant melanoma, and other tumors with "rhabdoid" features (such as an atypical teratoid/rhabdoid tumor).

[Meningioma with rhabdoid transformation: case report]

Meningiomas represent aproximatelly 30% of all intracranial tumors in autopsy studies. With an incidence of 2.3 per 100000, they are considered commom tumors in clinical practice. Twenty percent of the all intracranial tumors diagnosed in vivo are meningiomas. Most of these lesions are benign and the prognosis is intimatelly related to acessibility and ressectability of the lesion. Malignant meningiomas are rare lesions, representing between 1 to 11% of all meningiomas, varying with the definition of pathological criteria for malignancy used, and are categorized in atypical or malignant. Only recently rhabdoid transformation of meningiomas have been reported. We present a case of an extremelly aggressive rhabdoid meningioma in a 56 year-old woman. The tumor was surgically removed twice, with a lethal outcome due to local recurrence, despite maximum radiation and quimiotherapy, six months after the initial presentation.

Rhabdoid glioblastoma: a case report

The authors report a 16 year old girl with a supratentorial rhabdoid glioblastoma. The radiological features, histopathology and management of this rare variant of glioblastoma multiforme are discussed.

Malignant rhabdoid meningioma arising in the setting of preexisting ganglioglioma: a diagnosis supported by fluorescence in situ hybridization. Case report

A highly malignant brain neoplasm with rhabdoid morphological features emerged in the bed of a subtotally resected ganglioglioma in a 54-year-old retired nuclear submarine officer. A combined application of neuroimaging, immunohistochemical studies, electron microscopy, and fluorescence in situ hybridization (FISH) was used to establish the morphological identity of the tumor. The rhabdoid appearance of the tumor cells indicated either an especially malignant variant of rhabdoid meningioma or an atypical teratoid/rhabdoid tumor with an unusually late onset. Whereas immunohistochemical studies and electron microscopy could only be used to narrow down the differential diagnosis, FISH revealed loss of one copy of NF2 with preservation of the INI1 region on 22q, thus establishing the identity of the tumor.

Renal cell carcinoma with rhabdoid features: an aggressive neoplasm

AIMS

Only a few reports on renal cell carcinoma with rhabdoid features have been published. This study was performed to investigate the clinicopathological characteristics of renal cell carcinomas with rhabdoid features.

METHODS AND RESULTS

Among 253 cases of renal cell carcinoma in adults, eight cases with rhabdoid features were detected. Rhabdoid areas ranged from 10% to 90% of each of the cases. Seven of the eight cases were TNM stage III or IV, and four of the eight cases died within 8 months of surgery. Immunohistochemically, the rhabdoid areas were positive for CAM 5.2 (4/8), AE1/AE3 (6/8), epithelial membrane antigen (6/8) and vimentin (8/8), and negative for myogenetic markers (0/8). The mean MIB-1 labelling index in the rhabdoid areas was higher than that in the definite carcinomatous areas. Ultrastructurally, perinuclear whorls of intermediate filaments were demonstrated in three of the eight cases using paraffin-embedded blocks.

CONCLUSIONS

The rhabdoid areas in renal cell carcinoma have histological, immunohistochemical and ultrastructural similarities to malignant rhabdoid tumours. Renal cell carcinoma with rhabdoid features is a highly aggressive neoplasm and its malignant behaviour may be due to the high cell-proliferative activity of the rhabdoid areas. Rhabdoid features in renal cell carcinoma may represent the endpoint of clonal evolution of renal cell carcinoma (especially in clear cell type cases).

Evidence of recurrent atypical meningioma with rhabdoid transformation and expression of pyrogenic cytokines in a child presenting with a marked acute-phase response: case report and review of the literature

Children presenting with acute systemic illnesses that lack specific clinical or serological defining features may be diagnosed as having a chronic infection, an atypical systemic vasculitis or a connective tissue disease, but often turn out to have occult neoplasias. Cytokines have been implicated in causing many of the systemic effects in such cases. In this study, we describe the case of a 9-year-old boy presenting at an interval of 18 months with a marked acute-phase response due to a recurrent atypical meningioma with rhabdoid transformation of the tentorium cerebelli. Resection of the recurrent tumor was curative. We evaluated in detail the local and systemic production of cytokines released by the primary and the recurrent tumor. Blood and CSF samples were taken pre-, intra-, and postoperatively, and the production of IL-6, IL-1beta, and TNF-alpha was measured by enzyme-linked immunosorbent assays (ELISA). The level of IL-6 in CSF was about 150-fold increased before tumor resection, normalizing postoperatively. On the contrary, the levels of IL-1beta and TNF-alpha in CSF and of IL-6, IL-1beta, and TNF-alpha in serum were pre-, intra-, and postoperatively within normal limits. Cytokine production was also evaluated immunohistochemically, and confirmed strong IL-6 and TNF-alpha expression in the primary and the recurrent tumor, while expression of IL-1beta was lacking. The scattered MHC class II- and leukocyte common antigen (LCA)-expressing inflammatory cells, which were infiltrating exclusively the tumoral stroma, had no detectable cytokine immunoreactivity. We conclude that chronic IL-6 and TNF-alpha production by the tumor cells in this patient was responsible for the severe systemic illness with which he presented.

April 2001: a 70 year old woman with recurrent meningioma

The April Case of the Month (COM). The contributors report a case of a 70 year-old woman with recurrent meningiomas, one of which showed rhabdoid and lipomatous differentiation. Histopathological study of the first and second previous resections showed only typical meningothelial meningioma. On the third craniotomy, a new tumor specimen showed an admixture of classic meningothelial meningioma with lipomatous and rhabdoid foci. Immunohistochemical studies showed diffuse reactivity for epithelial membrane antigen and vimentin, as well as focal positivity for desmin and smooth muscle actin in the areas with rhabdoid features and S100 protein in the lipomatous foci. The presence of these three different and concomitant histological patterns only in the third surgical resection might support a metaplastic origin and, also, corroborates the concept that rhabdoid features are suggestive of an aggressive behavior.

Rhabdoid papillary meningioma

We have studied an uncommon case of rhabdoid papillary meningioma in a 15-year-old boy with a dura-based mass arising in the left posterior fossa. The patient exhibited prominent extracranial extension during the past 6 years, consisting of a mixture of both perivascular pseudopapillary growth and rhabdoid cytologic features of neoplastic meningothelial cells. The meningothelial features were evidenced by the focal whorl formation of tumor cells, coexpression of epithelial membrane antigen and vimentin, and ultrastructural findings of interdigitated cytoplasmic process and intercellular junction. However, the regional and histologic resemblances to ependymoma were further complicated by unexpected focal expression of glial fibrillary acidic protein, neurofilament, and alpha-smooth muscle actin of the tumor cells. The rhabdoid morphology was characterized by sheets of tumor cells with eccentric nuclei and abundant eosinophilic cytoplasm with often recognizable intracytoplasmic hyaline inclusions. These inclusions revealed ultrastructural paranuclear whorls of intermediate filaments, ruling out the other forms of intracytoplasmic eosinophilic inclusions resembling rhabdoid morphology. Diagnosis of an unusual rhabdoid papillary meningioma with aggressive behavior is resoluble by immunohistochemical and ultrastructural analyses.

Rhabdoid features in leiomyosarcoma of soft tissue: with special reference to aggressive behavior

The presence of rhabdoid cells has been reported in various types of malignant neoplasms and has been determined to be a predictor of aggressive behavior of neoplasms regardless of tumor histogenesis. One hundred and thirteen cases of leiomyosarcoma, selected from 1800 soft tissue sarcomas, were reviewed on hematoxylin and eosin sections, and immunohistochemical staining when available, and seven cases with rhabdoid features were retrieved. Clinicopathologic differences were analyzed to compare between cases with rhabdoid features and those without rhabdoid features. In the seven cases with rhabdoid features, two were intra-abdominal, and the others arose in external soft tissues including muscle, subcutis, and cutis. Patient age ranged from 33 to 84 years, three were female, and four were male. Tumor size ranged from 3 to 22 cm. Clinical evidence showed no differences from those cases without rhabdoid features. Histologically, one of the abdominal cases was epithelioid leiomyosarcoma. Two of the 7 cases were better subclassified as pleomorphic leiomyosarcoma, in which rhabdoid cells are diffusely scattered. In cases other than those with pleomorphic leiomyosarcomas, foci of anaplastic areas were observed, and collections of rhabdoid cells were present in those areas. Immunohistochemical examination of the cases confirmed myogenic differentiation, and showed rhabdoid cells being positive for vimentin and desmin in the inclusion bodies, and diffusely so for muscle actin in the cytoplasm. After dividing all the cases of leiomyosarcoma by their location, prognostic analysis was performed. Leiomyosarcoma of external soft tissue with rhabdoid cells showed a tendency for poorer prognoses than cases without rhabdoid features. On the contrary, retroperitoneal cases did not. This study indicates that rhabdoid features are associated with aggressive biological behavior in leiomyosarcoma of the external soft tissue.

Renal cell carcinoma with rhabdoid features

Neoplasms with rhabdoid features have been reported at many anatomic sites. In the kidney, rhabdoid tumors are typically found in children, whereas only rare examples have been reported in adults. Little is known of renal cell carcinomas (RCCs) that exhibit rhabdoid features. The objective of this study was to determine the incidence of RCC with rhabdoid attributes and characterize the histologic, immunophenotypic, and ultrastructural features by retrospective analysis of 480 consecutively identified cases of RCC in radical nephrectomy specimens. Immunohistochemical evaluation was performed in cases with rhabdoid foci using a panel of antibodies to pancytokeratin (pan-CK), CK7, CK20, epithelial membrane antigen (EMA), S-100 protein, desmin, vimentin, neuron-specific enolase (NSE), muscle-specific actin (MSA), smooth muscle actin (SMA), human melanoma, black-45 (HMB-45), and glial fibrillary acidic protein (GFAP). Electron microscopy was also performed in selected cases. The presence and extent of rhabdoid foci in relation to pathologic stage and grade were assessed. Twenty-three of 480 cases of RCC (4.7%) exhibited rhabdoid features. The 23 patients were all adults with a mean age of 61.8 years (age range, 33-84 yrs). Fifteen of the patients were men and eight were women. Histologically, the rhabdoid foci were typified by sheets and clusters of variably cohesive, large epithelioid cells with vesicular and often eccentric nuclei, prominent nucleoli, and large, paranuclear intracytoplasmic hyaline globules (inclusions). The presence of these rhabdoid features was related to high histologic Fuhrman grade of the nonrhabdoid carcinoma component, with an incidence of 0 of 84 grade I cases, eight of 300 grade 2 cases (2.6%), six of 70 grade 3 cases (8.9%), and nine of 26 grade 4 cases (34.6%; p = 3 x 10(-9)). The rhabdoid foci were all high grade. The presence of rhabdoid foci was also found in higher stage carcinomas. A total of 52% (12 of 23) of RCC cases with rhabdoid features exhibited extrarenal extension compared with 28% (24 of 92) of contemporary RCCs without rhabdoid features (p = 0.03). The size of the rhabdoid component ranged from 1 mm to more than 2 cm and comprised 1% to 50% of the renal mass. Immunoreactivity for vimentin (100%), NSE (79%), and panCK (56%) was present in the majority of cases. Substantial percentages of cases were immunopositive for EMA (47%) and S-100 protein (37%), with minimal to no immunohistochemical reactivity for CK7 (5%), SMA (5%), CK20 (0%), desmin (0%), MSA (0%), HMB-45 (0%), and GFAP (O%). A distinctive globular, paranuclear reaction pattern was found for the cytokeratin, EMA, and vimentin immunostains. Ultrastructurally, the rhabdoid cells had paranuclear intermediate filament aggregates or paranuclear condensation of organelles, often associated with peripheral vacuolization. Adult RCCs may harbor a rhabdoid component, and these neoplasms can be regarded as "composite" tumors. Rhabdoid elements are important to identify because of their high-grade nature, and association with high stage. Adult RCC with rhabdoid elements should be distinguished from pure rhabdoid tumors of kidney, in light of their clinicopathologic differences. Rhabdoid differentiation in adult renal cell carcinoma may represent clonal divergence and/ or evolution, and emergence of a particularly aggressive element.

Chordoid meningioma: a clinicopathologic study of 42 cases

The term chordoid meningiomas was first used by Kepes et al. in 1987 to describe a meningeal tumor in young patients associated with microcytic anemia and/of dysgammaglobulinemia. Such tumors were composed of spindle or epithelioid cells disposed in chordoma-like clusters and cords in a myxoid matrix and often featured a prominent lymphoplasmacellular infiltrate. Our study includes 42 chordoid meningiomas that represented 0.5% of all meningiomas operated at Mayo Clinic during the interval 1975 to 1997. The male to female ratio was 1:1 and the age range was 12 to 77 years (mean, 47.4 yrs). Only two (5.2%) occurred in children. The majority (88%) were large and supratentorial. No manifestation of systemic disease was noted. Chordoid elements comprised 10% to 100% of the tumors: 34 (81%) were more than 50% chordoid. Thirty-seven tumors (88%) were classified as typical and five as atypical. Lymphoplasmacytic infiltrates varied, being moderate in 10 cases (23.8%), mild in 15 (35.7%), and absent in 17 (40.5%). In 14 (42%) of the 33 cases with available follow up, one or more recurrences were noted. All but one recurrent tumor had been subtotally resected. In 86% of recurrent tumors, the primary lesion was more than 50% chordoid in pattern and contained little or no inflammatory infiltrate. In our experience, chordoid meningiomas are primarily tumors of adults, lack sex predilection, are unassociated with systemic manifestations, and uniformly recur when subtotally excised.

Middle ear meningiomas

Meningiomas arising in or presenting as middle ear lesions are relatively uncommon. This study retrospectively reviews the clinicopathologic features of six meningiomas arising in or extending into the middle ear. The patients comprise five women and one man ranging in age from 45 to 67 years (median, 55 years) at the time of surgery. Five tumors arose in the posterior fossa or temporal bone region and one tumor arose from the auditory canal itself. Three tumors arose on the right side and three on the left. Duration of symptoms before surgery involving the middle ear was known in five patients and ranged from 2 to 13 years (median, 10 years). Symptoms at presentation included gait or balance problems (n = 3), chronic otitis media (n = 2), diplopia (n = 2), hearing loss (n = 2), pain (n = 1), aural polyp (n = 1), and tinnitus (n = 1). Histologically, all six tumors resembled a syncytial (meningotheliomatous) meningioma. Psamomma bodies were noted in two tumors and two tumors demonstrated mild nuclear pleomorphism. None of the tumors demonstrated histologic features of atypical meningioma. Follow-up information was available in five patients. Four patients had prior surgery for removal of posterior fossa temporal bone meningiomas and developed recurrences involving the auditory canal 60 to 84 months after surgery. At the time of most recent follow-up examination, three patients were alive with evidence of tumor (65, 112, and 214 months), one patient was alive with no evidence of tumor (99 months), one patient died in the postoperative period of sepsis and pneumonia following resection of a middle ear recurrence (64 months), and one patient was lost to follow-up analysis. Meningiomas arising in or extending to the middle ear canal are unusual. They more commonly arise in woman and in most cases involve extension of intracranial/cranial tumors into the canal.

Pineal malignant rhabdoid tumor with chondroid formation in an adult

A pineal tumour in a 27-year-old male is presented with the characteristic histological features of a pineal malignant rhabdoid tumor (MRT) with chondroid formation. Occasionally, tumor cells contained a single well-demarcated hyaline globular inclusion within the cytoplasm adjacent to the nucleus. The stroma of these tumors tends to be densely hyalinized and become chondroid. Immunohistochemical staining was positive for vimentin, epithelial membrane antigen, chromogranin A, synaptophysin, neuron-specific enolase, S-100 protein, and muscle actin. Despite surgery and radiochemotherapy, the tumor recurred in the pineal region and metastasized to the lower lobe of right lung. The patient died 2 years after the initial diagnosis. This is the second published case of central nervous system-MRT appearing in an adult. The clinical and pathological features of pineal MRT in this patient are presented.

Primary pulmonary malignant meningioma

Fewer than 20 cases of primary pulmonary meningioma have been reported. Most of these cases have been histologically and clinically benign. We report an unusual case of primary pulmonary malignant meningioma with atypical histologic features and malignant behavior. A computed tomography scan of the head did not show evidence of tumor. The right upper lobe mass was resected and showed features of an atypical meningioma with loss of architectural pattern, mild nuclear pleomorphism, increased mitotic counts (up to 15 mitotic figures per 10 high power fields), and focally prominent nucleoli. Focally, cells with rhabdoid features were identified. The tumor's immunohistochemical and ultrastructural profiles were consistent with a meningioma. The tumor stained negative for estrogen and focally positive for progesterone receptors and had a MIB-1 labeling index (marker of cell proliferation) of 9.2%. Approximately 5 months after the initial resection, the patient experienced a tumor recurrence with multiple lymph node metastases, spread to the middle and lower lobes of the right lung, and metastasis to the diaphragm. Rarely, primary pulmonary meningiomas may present as high-grade malignant lesions.

"Malignancy" in meningiomas: a clinicopathologic study of 116 patients, with grading implications

BACKGROUND

Due to the rarity of malignancy in meningiomas, prior studies have been limited to small series. Controversies regarding the definition of malignant meningioma have complicated matters further. Although histologic anaplasia and extracranial metastasis are established criteria, the former is difficult to define and the latter represents a clinical finding. Traditionally, brain invasion has also been accepted, although this has recently been debated. In a prior series, the authors were unable to prove that 23 meningiomas that had invaded the brain were more aggressive than atypical meningiomas.

METHODS

The authors expanded their analysis to include 116 patients diagnosed with "malignant meningioma" due to brain invasion, frank anaplasia (20 mitoses per 10 high-power fields or histology resembling carcinoma, sarcoma, or melanoma), and/or extracranial metastasis. Patients were followed until death or for a median of 3.7 years.

RESULTS

Survival time was highly variable, ranging from 10 days to 24 years. In multivariate analysis, histologic anaplasia (P=0.0035), subtotal resection (P=0.0038), 20 mitoses per 10 high-power fields (P=0.0071), and nuclear atypia (P=0.0068) were associated with poor survival. Of the 89 cases of meningioma that had invaded the brain, 23% were otherwise benign, 61% were otherwise atypical, and 17% were frankly anaplastic. Those without anaplasia behaved similarly to atypical meningiomas from the authors' prior study. In contrast, anaplastic meningiomas were usually fatal, associated with a median survival of 1.5 years.

CONCLUSIONS

Based on these findings, the authors suggest that brain invasion constitutes an additional criterion for the diagnosis of atypical meningioma (World Health Organization [WHO] Grade II), whereas frank anaplasia indicates high grade (WHO Grade III-IV) malignancy.

"Rhabdoid" meningioma: an aggressive variant

It is has been suggested that rhabdoid morphology is associated with a poor prognosis, regardless of tumor histogenesis. We report a series of 15 meningiomas with rhabdoid features. Nine patients had undergone multiple resections. In six, the rhabdoid component was histologically apparent only in recurrences. Rhabdoid morphology was defined as sheets of loosely cohesive cells with eccentric nuclei and hyaline, paranuclear inclusions. Ultrastructurally, the latter consisted of whorls of intermediate filaments often entrapping lysosomes or other organelles. Meningothelial features included whorl formation and nuclear pseudoinclusions, immunohistochemical coexpression of vimentin and epithelial membrane antigen, and the ultrastructural finding of interdigitating cell membranes and intercellular junctions. At the histologic level, a conventional meningioma component was noted in most tumors; only four lesions were entirely rhabdoid. Histologic malignancy (brain invasion or anaplasia) was observed in nine cases, another two tumors being considered malignant on the basis of extracranial metastasis. In the majority, increased cell proliferation was evidenced by a high mitotic rate or MIB-1 LI. At last follow-up, 13 patients (87%) had experienced at least one recurrence and 8 (53%) were dead of disease. Median time to death was 5.8 years after initial surgery and 3.1 years after the first appearance of rhabdoid morphology. Our findings corroborate those from a smaller series recently reported by Kepes et al. on the same entity (Kepes JJ, Moral LA, Wilkinson SB, Abdullah A, Llena JF. Rhabdoid transformation of tumor cells in meningiomas: A histologic indication of increased proliferative activity. Report of four cases. Am J Surg Pathol 1998;22:231-8). They further suggest that rhabdoid meningiomas are highly aggressive tumors and that the rhabdoid phenotype represents a marker of malignant transformation in meningiomas.