Malignant rhabdoid tumor of brain: an aggressive clinical entity

Atypical teratoid/rhabdoid tumor in adult: case series and an integrated survival analysis

BACKGROUND

Atypical teratoid/rhabdoid tumor (AT/RT) is well documented in children but less so in adults because of its rarity.

METHOD

We report a series of five cases, a literature review and quantitative analysis of the survival outcome of adult AT/RT patients.

RESULTS

Seventy-four patients including our five cases (male: female = 16: 58) were evaluated, whose median age was 32.5 years (18-80 years). The commonest location was the sellar region. Median overall survival (OS) was 12.5 months (0.5-204.00 months). Chemotherapy was associated with OS (HR: 0.349, 95%CI: 0.176-0.694, p = 0.003), while other factors did not influence OS. From Kaplan-Meier analysis, surgery combining postoperative chemotherapy and radiotherapy was associated with better prognosis (Log Rank: χ2 = 14.662, p = 0.001).

CONCLUSIONS

Adult AT/RT is commoner in females and tends to recur rapidly after surgical resection. Chemotherapy may provide a survival benefit. Surgery combined with postoperative chemotherapy and radiotherapy was associated with better prognosis for adult AT/RT patients, though the overall prognosis was still poor.

Atypical Teratoid/Rhabdoid Tumor of the Nervous System in Adults: Location-Related Features and Outcome

BACKGROUND

Atypical teratoid/rhabdoid tumor (AT/RT) of the nervous system is a rare and highly malignant neoplasm, mainly affecting children, first recognized as a pathologic entity in 1996 and added to the World Health Organization Classification of the Tumors of the Central Nervous System in 2000. AT/RT is even rarer among adults and is associated with a worse prognosis. The aim of the present study was to analyze the different tumor features according to the location in adults.

METHODS

A comprehensive and detailed literature review of AT/RTs in adults was made. The demographic, management, and outcome data associated with tumor location were analyzed and compared; histopathologic and molecular features were also discussed. Furthermore, we added our personal case with brain hemispheric localization and reported a progression-free survival of 103 months after gross total resection and adjuvant radiotherapy showing a peculiar histopathologic pattern.

RESULTS

Female sex is mainly affected by AT/RT on median localizations, both intracranial and spinal, and by all sellar region cases. Gross total resection is mainly achieved among lateral compared with median localizations. Combined radiotherapy and chemotherapy is the most adopted adjuvant treatment in all tumor localizations and is related to better outcome. Postoperative death is reported only among sellar region localizations, whereas brain hemispheric cases show the best overall survival.

CONCLUSIONS

AT/RTs show different and peculiar features according to their location, which significantly affects the outcome; precise knowledge of them helps the neurosurgeon in planning the best strategy for treatment.

Adult Pineal Region Atypical Teratoid Rhabdoid Tumor: A Case for Aggressive Surgical and Chemoradiation Management with Comprehensive Literature Review

BACKGROUND

Atypical teratoid rhabdoid tumor (ATRT) is a rare, highly malignant central nervous system neoplasm classified as an embryonal grade IV neoplasm by the World Health Organization. ATRT generally occurs in children younger than 3 years, with 85 pathologically confirmed cases reported in adults. It is most commonly supratentorial, with only 9 confirmed adult cases localized to the pineal region.

CASE DESCRIPTION

The case is described of a 29-year-old man with a history of chronic migraines and a previously negative computed tomography scan of the head presenting with worsening headaches and new-onset diplopia with upward gaze palsy. Computed tomography and magnetic resonance imaging showed a hemorrhagic pineal mass with extension into the right thalamus. After resection, the immunohistochemical staining and cytogenetic profile proved consistent with ATRT, making it the ninth reported case of pineal ATRT in an adult, which was treated aggressively with good outcome.

CONCLUSIONS

Adult ATRT is rare, especially in the pineal region, with only 9 cases reported. Because of the aggressiveness, ATRT must be considered in the differential diagnosis of pineal region lesions because early diagnosis and aggressive treatment are key to prolonged survival.

Primary Brain Rhabdomyosarcoma Causing Extracranial Metastases: Case Report with Narrative Review of Atypical Presentations and Their Diagnostic Challenges

BACKGROUND

Rhabdomyosarcoma is a rare malignant tumor originating from striated muscle cells. It accounts for only 3% of all soft tissue sarcomas in adults, and its metastases can also reach the central nervous system. Only sporadic cases of primary brain rhabdomyosarcoma (PBRMS) have been reported so far.

CASE DESCRIPTION

We discuss the atypical presentation and diagnostic challenge of PBRMS in a 65-year-old man. He presented with a 3-day history of progressive right hemiparesis caused by an unspecific left frontoparietal heterogeneously enhancing lesion. Total body computed tomography and positron emission tomography scans performed at baseline did not reveal other secondarisms. The patient underwent radical excision of the lesion, which allowed to establish the diagnosis, with immunohistochemical staining positive for desmin and myogenin. Stereotactic radiotherapy guaranteed local disease control; nonetheless, the patient also required adjuvant chemotherapy when he developed large right lung metastases 6 months postoperatively.

CONCLUSIONS

PBRMS can be hardly distinguished from other malignant brain tumors during preoperative radiologic workup; only histology can raise the suspicion of primary or metastatic rhabdomyosarcoma, depending on the presence of other distant lesions. Our review of the literature demonstrates that prognosis is poor: 44% of patients die within 1 year from diagnosis. Overall, survival seems to correlate with radical resection, tolerance of stereotactic or if necessary full neuraxis radiotherapy, and adjuvant chemotherapy. Given the high relapse rate, close monitoring and restaging are imperative.

Atypical Teratoid Rhabdoid Tumor: Two Case Reports and an Analysis of Adult Cases with Implications for Pathophysiology and Treatment

We present the first quantitative analysis of atypical teratoid rhabdoid tumors (ATRT) in adults, including two patients from our own institutions. These are of interest as one occurred during pregnancy and one is a long-term survivor. Our review of pathological findings of 50 reported cases of adult ATRT leads us to propose a solely ectodermal origin for the tumor and that epithelial–mesenchymal transition (EMT) is a defining feature. Thus, the term ATRT may be misleading. Our review of clinical findings shows that ATRT tends to originate in mid-line structures adjacent to the CSF, leading to a high rate of leptomeningeal dissemination. Thus, we hypothesize that residual undifferentiated ectoderm in the circumventricular organs, particularly the pituitary and pineal glands, is the most common origin for these tumors. We note that if growth is not arrested soon after diagnosis, or after the first relapse/progression, death is almost universal. While typically rapidly fatal (as in our first case), long-term remission is possible (as in our second). Significant predictors of prognosis were the extent of resection and the use of chemotherapy. Glial differentiation (GFAP staining) was strongly associated with leptomeningeal metastases (chi-squared p = 0.02) and both predicted markedly worse outcomes. Clinical trials including adults are rare. ATRT is primarily a disease of infancy and radiotherapy is generally avoided in those aged less than 3 years old. Treatment options in adults differ from infants in that cranio-spinal irradiation is a viable adjunct to systemic chemotherapy in the adult population. Given the grave prognosis, this combined approach appears reasonable. As effective chemotherapy is likely to cause myelosuppression, we recommend that stem-cell rescue be available locally.

Atypical teratoid/rhabdoid tumor in sellar turcica in an adult: A case report and review of the literature

Background:

Atypical teratoid/rhabdoid tumor (AT/RT) is a rare central nervous system tumor composed of primitive rhabdoid cells that may differentiate along neuroectodermal, mesenchymal and epithelial lineages. AT/RT in adults is rare but not completely exceptional. It generally arises from the posterior fossa of infants, but the broad majority of the reported AT/RT in adults manifested supratentorially with the exception of four cases that arose in the cerebellum and two that arose in the spinal cord.

Case Description:

A 44-year-old female complained of visual disturbance. We performed craniotomies twice and removed partially for each time, but any malignant cells were not found in the specimens. Finally, we determined histological diagnosis from the extended lesion. She died of respiratory failure 17 months after the initial treatment.

Conclusion:

AT/RT should be considered in the differential diagnosis of a sellar lesion in adult patients. However AT/RT is rare in adults, the appropriate immunohistochemical evaluation should be performed to diagnose this rare entity.

Aggressive rhabdoid meningioma with osseous, papillary and chordoma-like appearance

Meningiomas are the most common primary intracranial tumors. They are usually benign and slowly growing; however, they may show histologically malignant features categorizing them into grade II or III of World Health Organization (WHO) classification. Rhabdoid meningioma (RM) is an uncommon meningioma variant categorized as WHO grade III. The clinical course of RM is determined by local recurrences, invasion of adjacent brain and/or dura, widespread leptomeningeal dissemination, remote metastases and fatal clinical outcome. Herein we report a case with recurrent aggressive left occipital parasagittal region RM in which the patient initially declined radiation treatment. The tumor was resected four times in 5 years. Histopathological examination revealed a rhabdoid meningioma with metaplastic, papillary and chordoid differentiation. Six months after her fourth operation the patient died of progressive disease. RM is a rare subtype of malignant meningioma and the role of different adjuvant therapeutic options are still unknown. Clinical presentation, radiological features and pathologic findings of this uncommon tumor are discussed.

Radiological image features of the atypical teratoid/rhabdoid tumor in adults: a systematic review

PURPOSE

Atypical teratoid/rhabdoid tumor (AT/RT) occurs in children less than 3 years old, and has a very poor prognosis. AT/RT seldom occurs in adult. We have experienced four cases of AT/RT at our institute. The purpose of this study is to evaluate the radiological image findings of adult-onset AT/RT and to conduct a systematic review.

METHODS

Image findings of four AT/RTs in our institute were retrospectively evaluated by an experienced neuroradiologist. If the images were unavailable, image findings were evaluated from the former image interpretation report. We assembled papers of adult-onset AT/RT (n = 38) and evaluated the image findings.

RESULTS

AT/RT occurs in a variety of sites (spinal region, pineal region, suprasellar region, jugular foramen, and so on). High density on computed tomography (CT) was seen in 10 of 11 cases; mixed intensity in T2-weighted image was seen in 13 of 18 cases; and high intensity on diffusion-weighted image (DWI) was seen in 3 of 3 cases. Contrast enhancement was observed in all cases in which images were available.

CONCLUSIONS

We have experienced four adult-onset AT/RT cases at our institute and have evaluated image findings through systematic review. The image findings of high density on CT, high intensity on DWI, with low apparent diffusion coefficient, and a heterogenous component should lead to an inclusion of AT/RT in the differential diagnosis of a tumor; these findings may be able to suggest AT/RT; however, they cannot make the diagnosis.

Malignant brain tumor with rhabdoid features in an adult

Rhabdoid tumor (RT) of the central nervous system is an uncommon and aggressive neoplasm that usually affects pediatric patients. Currently, these tumors are classified as malignant RT or atypical teratoid/RT. Another entity of intraparenchymal brain tumor with a rhabdoid component is the extremely rare rhabdoid glioblastoma. A 23-year-old woman presented with a malignant RT in the right thalamus. The tumor was adjacent to the right lateral ventricle and was partially resected. Histological examination revealed prominent proliferation of rhabdoid cells, which is consistent with a diagnosis of malignant RT; the typical features of glioblastoma were not observed. The tumor cells stained positively for integrase interactor-1 and glial fibrillary acidic protein. Therefore, the tumor may have originated from glial components. Genetic analysis using comparative genomic hybridization showed a deoxyribonucleic acid copy-number gain on chromosome 7 but not on chromosome 22. The tumor did not respond to chemotherapy or radiotherapy, and the patient survived for only 4 months after surgery. The present case of malignant RTs shows certain similarities with those of rhabdoid glioblastoma. Further accumulation and analysis of data, including data from genetic analyses, may lead to the identification of a new type of malignant RT.

Atypical teratoid/rhabdoid tumors in adults: a case report and treatment-focused review

Atypical teratoid/rhabdoid tumor is predominantly a childhood tumor and has only been rarely reported in adults; therefore, treatment regimens are often extrapolated from the pediatric experience. Typically, children are treated with craniospinal radiation therapy which is often followed by systemic chemotherapy. Employing pediatric regimens to treat this tumor in adult patients poses a particular risk for myelosuppression, as the prescribed doses in pediatric protocols exceed those tolerated by adults, and conventional craniospinal radiation can be associated with prolonged myelotoxicity and a depletion of the bone marrow reserve in vertebrae of adults. Here we present a case of a woman with a pineal region atypical teratoid/rhabdoid tumor, an unusual adult cancer presenting in an atypical location. This is followed by a review of the disease in adult patients with an emphasis on treatment and suggestions to minimize myelotoxicity.

Atypical teratoid/rhabdoid tumor of the pineal region in an adult

An atypical teratoid/rhabdoid tumor (AT/RT) is a highly malignant embryonal tumor most often occurring in the posterior fossa in children younger than 3 years of age. Adult cases of AT/RT are very rare, and 27 cases with a diagnosis of either AT/RT or (malignant) rhabdoid tumor have been reported to date. The authors report an adult case of an AT/RT occurring in the pineal region with molecular cytogenetic and immunohistochemical confirmation. A 33-year-old woman presented with a 2-month history of headache and blurred vision progressing to diplopia, and was admitted emergently due to deteriorating mental status. An MR image showed a heterogeneously enhancing mass involving the posterior third ventricle and pineal region with mild hydrocephalus. She underwent a subtotal resection of the tumor and was then treated with chemoradiation. Thirteen months after surgery, she was still alive with radiological evidence of recurrence/residual lesions. Histological sections showed epithelioid cellular sheets of rhabdoid tumor cells with scattered mitotic figures. Immunohistochemically, the tumor cells were diffusely and strongly positive for epithelial membrane antigen and vimentin, and showed focal expression of glial fibrillary acidic protein, pancytokeratin, and neurofilament protein. Loss of nuclear immunoreactivity for INI1 protein was observed. Fluorescence in situ hybridization analysis showed monosomy 22. Histologically, this tumor consisted exclusively of epithelioid tumor cells with rhabdoid features. The differential diagnoses include rhabdoid glioblastoma, metastatic carcinoma, and rhabdoid meningioma. Molecular testing to identify monosomy 22 or deletions of the chromosome 22q11 containing the INI1/hSNF5 gene and/or immunohistochemical staining with INI1 antibody is of great importance for the diagnosis of this tumor.

Cerebral tumor with extensive rhabdoid features and a favorable prognosis

This 32-year-old woman, 27 weeks pregnant, harbored a cystic mass with a solid component in the left frontal lobe. Histologically, the lesion was hypercellular and contained a diffuse sheet of eosinophilic cells of various sizes. The cells were almost round and had a few prominent, eccentrically placed, hyperchromatic nuclei of various sizes. Immunohistochemically, the tumor was reactive for vimentin, epithelial membrane antigen, cytokeratin AE1/AE3, smooth muscle actin, and BAF47/INI-1, and negative for glial fibrillary acidic protein, neurofilament protein, S100 protein, CK7, CK20, HMB-45, MIC2, and Bcl-2. The Ki 67 labeling index was 4.2%. Comparative genomic hybridization analysis revealed aberrations of the chromosomal copy number of +7 and −10. This tumor could not be categorized according to the present World Health Organization classification. Results of staining with glial fibrillary acidic protein were not consistent with a glioma, and staining with INI-1 was inconsistent with atypical teratoid/rhabdoid tumor. The tumor was therefore designated as a “cerebral tumor with extensive rhabdoid features.”

Childhood atypical teratoid rhabdoid tumor of the central nervous system: a meta-analysis of observational studies

PURPOSE

Therapy for central nervous system (CNS) atypical teratoid rhabdoid tumor (ATRT) is controversial. We describe 4 children treated with sarcoma-like therapy and review the literature to evaluate outcome in relation to treatment modalities.

PROCEDURE

Reports from 1995 to 2007, describing clinical features of children (< or =18 years) were reviewed for details of demography, therapy, and outcome. Kaplan-Meier survival analyses were used to study the impact of clinical features, demography, and therapy on overall survival (OS).

RESULTS

The median OS for patients treated with multiagent chemotherapy (n=79) was 17.3 months (range, 1.5-93 mo); unrelated to age at diagnosis, sex, tumor site, and extent of resection. Overall mortality was 67%. Disease progression (craniospinal spread in 58%) was the major cause of death. Patients (n=30) treated with intrathecal (IT) chemotherapy had significantly higher 2-year OS [64% (95% confidence interval, 46.5-82.0) vs. 17.3% (95% confidence interval, 5.4-29.3); P<0.0001] and lower prevalence of distant CNS metastasis compared with those without IT therapy (n=49) (20% vs. 59.2%; P=0.001).

CONCLUSIONS

Despite dismal OS, multimodal therapy can induce remission even in metastatic CNS ATRT with partial resection. IT chemotherapy results in higher OS and, because of an overall high rate of distant relapse, should be considered in future trials.

Primary malignant rhabdoid tumour of the brain in adults

Malignant rhabdoid tumour (MRT) was described for the first time in the kidney, and is rarely reported in the brain. Most rhabdoid tumours affect infants and young children and there have been only isolated adult patients reported. The optimal treatment for this very aggressive tumour has not yet been established. We describe the clinical and pathological features of a rare primary malignant rhabdoid tumour of the brain in a 27-year-old pregnant female. The literature is reviewed briefly and the role of the INI1 gene in adult MRTs and the also possible interactions between MRTs and pregnancy are discussed.

Atypical teratoid/rhabdoid tumor of the central nervous system in an 18-year-old patient

OBJECTIVE

Atypical teratoid/rhabdoid tumors are aggressive neoplasms of the central nervous system occurring mainly in the early childhood and rarely in adults. We described a case of this tumor in an 18-year-old male patient without previous medical history.

MATERIAL AND METHODS

The neoplasm was localized in the right frontotemporal area of the brain and was totally excised. The specimen was fixed in formalin and embedded in paraffin. The histological and immunohistochemical features of the neoplasm were assessed, while sequencing analysis as well as interphase fluorescence in situ hybridization (FISH) were performed.

RESULTS

Histological and immunohistochemical analysis demonstrated atypical rhabdoid cells strongly and diffusely positive for EMA and Vimentin as well as focally immunoreactive for SMA and GFAP. Additionally, though no abnormalities detected in the coding sequence of the INI1 gene, interphase FISH studies were consistent with a homozygous deletion of the INI1 gene in the majority of examined nuclei. INI1 immunostaining demonstrated diffuse loss of nuclear INI1 expression in tumor cells. Taken together, the results were consistent with a diagnosis of atypical teratoid/rhabdoid tumor (ATRT).

CONCLUSIONS

26 previous cases of ATRT have been reported in adults, thus far. To our knowledge, this is the eighth case of an ATRT reported in an adult patient having genetic confirmation and the first one in which the tumor is, partly, localized in the right temporal area of the brain. This unusual presentation underlines the necessity of considering this devastating neoplasm in the differential diagnosis of malignant brain tumors of young adults.

Atypical teratoid rhabdoid tumor (AT/RT) in adults: review of four cases

Atypical teratoid/rhabdoid (AT/RT) tumor is a rare, highly malignant tumor of the central nervous system (CNS) most commonly found in children less than 5 years of age. Although the vast majority of cases are diagnosed in young children, there have been isolated case reports in adults. Since its histological appearance can be confused with other tumors, especially in adults, separating AT/RT from other neoplasms may be difficult. In many instances, a reliable diagnosis is not possible without demonstrating the lack of nuclear INI1 protein expression by immunohistochemical methods. The patients (three males and one female) ranged in age from 23 to 42 years (mean age, 32 years). Radiographically, two tumors were localized in the right fronto-parietal region, one was frontal and the other was found in the left temporal lobe. Varying degrees of hydrocephalus and heterogeneous enhancement were present on MRI. In all cases, diagnosis during intraoperative consultation and preliminary diagnosis was different from the final diagnosis after immunohistochemical analysis. Immunohistochemical staining showed that the tumor cells were positive for vimentin and reacted variably for keratin, epithelial membrane antigen (EMA), synaptophysin, neurofilament protein, CD34, and smooth muscle actin (SMA). All were negative for GFAP, S-100, desmin and CD99. Three of the four cases lacked nuclear expression of INI1. One patient is alive with no evidence of disease 17 years after the diagnosis. In adult examples of AT/RT, the diagnosis requires a high index of suspicion, with early tissue diagnosis and a low threshold for investigation with INI1 immunohistochemistry to differentiate this entity from other morphologically similar tumors. Although the prognosis is dismal in pediatric population, long term survival is possible in adult AT/RT cases after surgery and adjuvant radiotherapy and chemotherapy.

Atypical teratoid/rhabdoid tumor of the spine in an adult: case report and review of the literature

Atypical teratoid/rhabdoid tumors (AT/RTs) are rare, malignant brain tumors which occur almost exclusively in infants and young children. There have been only 17 cases of AT/RT in adults reported in the medical literature and the rarity of this tumor makes the diagnosis in adults difficult. We describe a case of an AT/RT of the spinal cord in an adult. A 43-year old woman presented with neck and left upper extremity pain. An MRI demonstrated a mass lesion in the dorsal spinal cord extending from C4 to C6. The patient underwent a C3 through C7 laminectomy. In consultation with senior pathologists at other institutions, the lesion was initially diagnosed as a rhabdoid meningioma. Molecular genetic studies revealed monosomy 22 and loss of expression of the INI1 gene in 22q11.2. Subsequently, immunohistochemical studies revealed the absence of INI1 gene expression in the malignant cells, supporting the diagnosis of AT/RT. The patient underwent three additional surgical procedures for recurrent disease throughout the neuraxis secondary to leptomeningeal spread of the tumor. Despite aggressive surgical resection, adjuvant chemotherapy and radiation therapy, the patient succumbed to the disease two and a half years after her initial presentation. An unrestricted autopsy was performed. To our knowledge, this is the first case of a spinal atypical teratoid/rhabdoid tumor in an adult fully documented with molecular, immunohistochemical, cytogenetic and autopsy findings.

Atypical teratoid/rhabdoid tumor: the controversy behind radiation therapy

To date, approximately 200 cases of atypical teratoid/rhabdoid tumor (AT/RT) of the central nervous system have been described in the literature. This CNS tumor tends to present at an age of less than 3 years, and most patients succumb to their disease within 1 year of diagnosis. Prior to the rise in utilization of immunohistochemical (IHC) testing in the late 1990s, this tumor was likely mistaken as medulloblastoma and treated as such. However, lessons learned from regimens based upon medulloblastoma have revealed that AT/RT requires more aggressive treatment. A significant portion of patients die of local recurrence in spite of aggressive surgery and chemotherapy. As most patients with AT/RT present as infants or young children, radiation therapy has been a less than standard treatment option. However, recent evidence suggests that long-term survival can occur with use of more aggressive treatment approaches including dose-intense chemotherapy as well as adjuvant radiation therapy. A standardized and effective approach to treating this usually fatal tumor remains elusive, and the role of radiation therapy presents a particular dilemma as young patients with this disease may experience devastating late effects of therapy if they achieve a long-term survival. Review of the literature reveals an association between initial radiation therapy and the ability to achieve a prolonged survival. Our review underscores the importance or enrolling patients in multi-institutional prospective studies to further investigate the value of radiation to treat this pediatric neoplasm.

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.

Atypical teratoid/rhabdoid tumors of the central nervous system

Atypical teratoid/rhabdoid tumor (AT/RT) is a highly malignant central nervous system neoplasm that usually affects very young children and is typically deadly despite very aggressive treatment. Considered rare, the tumor was not recognized as a distinct entity until the 80's, due to its similar features with other primitive tumors. Although AT/RT has become increasingly recognized, published data has been based on small series and are retrospective. Based on these data, there are occasional long-term survivors, most of whom received intensive multi-modal therapy. AT/RT is the first pediatric brain tumor for which a candidate tumor suppressor gene has been identified. A mutation or deletion in the INI1 gene occurs in the majority of AT/RT tumors. The function of the gene is not yet understood. Prospective clinical and biologic trials are greatly needed to understand the efficacy of therapeutic interventions, as well as the role of the gene.

Atypical teratoid rhabdoid tumors of childhood: diagnosis, treatment and challenges

Atypical teratoid rhabdoid tumor of the brain was described as a unique entity in the late 1980s. It occurs primarily in early childhood but the true incidence of the disease is not yet known. At presentation, the differential diagnosis includes medulloblastoma, primitive neuroectodermal tumor, ependymoma and choroid plexus carcinoma. Atypical teratoid rhabdoid tumor behaves in a very aggressive manner and while cure is possible for a small minority of patients, no standard or effective therapy has been defined for most patients. Since its first description, considerable pathologic, cytogenetic and molecular characterizations, as described in this review, have been accomplished that provide insight into the possible molecular etiology of the disease and of malignant rhabdoid tumors that occur outside the CNS. Co-operative group clinical trials that focus solely on atypical teratoid rhabdoid tumor are needed that incorporate biologic studies along with evaluations of aggressive treatment approaches. The goal of these trials should be to increase the cure rate for children with atypical teratoid rhabdoid tumor and further increase our understanding not only of atypical teratoid rhabdoid tumor, but also of other pediatric brain tumors.

Malignant rhabdoid tumor in a pregnant adult female: literature review of central nervous system rhabdoid tumors

Rhabdoid tumors of the central nervous system are uncommon, aggressive childhood malignancies. The 13 described adult cases comprise both primary CNS tumors and malignant transformation of previously existing gliomas, meningiomas, and astrocytomas. Central nervous system rhabdoid lesions of adults have been diagnosed as primary malignant rhabdoid tumors, atypical teratoid/rhabdoid tumors, and more recently, rhabdoid glioblastomas. We report a case of a 20-year-old woman in her 30th week of pregnancy who presented with headache, nausea and blurry vision. MRI revealed a large rim-enhancing mass of the right occipital lobe. Gross total resection was achieved via a right parietal-occipital craniotomy. Pathologic evaluation revealed histology, electron microscopy and immunohistochemistry consistent with the diagnosis of malignant rhabdoid tumor. FISH studies were negative for the INI-1 genetic mutations and chromosome 22q deletion associated with childhood atypical rhabdoid/rhabdoid tumor in 75% of cases. The patient delivered her infant via caesarian section prior to initiating further therapy. We briefly describe the characteristics and current understanding of rhabdoid tumors, and review the literature comparing the 12 other cases of central nervous system rhabdoid tumors in adults. Furthermore, we consider and discuss the implications of this case being the second presentation of MRT during pregnancy in only six adult female patients.

Primary malignant rhabdoid tumor of the central nervous system--a comprehensive review

This paper presents the case of an eight-year-old girl who presented with headache and vomiting and was found to harbor a right fronto-temporo-parietal, partially cystic and centrally solid tumor that measured 11 x 8 x 7 cm. This vascular tumor was gross totally removed. The initial histopathologic diagnosis was hemangiopericytoma and the patient received a total dose of 5330 cGy of external cranial radiation. Twelve months later, the patient presented with left lower quadrant pain and limping and the spinal MR scans showed metastases at T4-5, T7, T12-L1 and L3 levels. The voluminous lesion at T12-L1 was surgically removed. Histopathological examination of both specimens revealed that both tumors in fact were malignant rhabdoid tumor (MRT). The patient did not benefit from spinal surgery and died 4 months later. A review of the literature has shown that since Briner et al'. first report in 1985 [Pediatr Pathol 3: 117-118, 1985], 100 MRT cases have been published. More than two-thirds of reviewed cases presented with local recurrence or subarachnoid spread after a mean period of 6.9 months after diagnosis and died two months later. Infratentorial and pineal location and surgery limited to biopsy were poor prognostic indicators. Twenty-two cases remained alive at a mean period of 24.5 months. The longest survival with an intracranial MRT was 65 months. Of those remaining alive, 15 had no evidence of disease (NED). Our case is the first MRT case immunopositive for HMB-45 and has also shown that the MRT cells grow aggressive over time as demonstrated by a four-fold increase in MIB-1 labeling index.

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.

Chromosome 22q deletions in atypical teratoid/rhabdoid tumors in adults

Atypical teratoid/rhabdoid tumors (AT/RTs) are rare, malignant brain tumors that usually occur in the posterior fossa. Both AT/RT and the analogous tumor outside the brain, malignant rhabdoid tumor, share a polyphenotypic immunoprofile and frequent 22q deletions with inactivation of the IN11/hSNF5 gene. Reports, so far, indicate that AT/RTs occur almost exclusively in children, most of whom are 5-years-old or less. The rarity of the tumor and the polyphenotypic immunoprofile, characterized by antigen expression that is often patchy, make diagnosis in adults difficult and controversial. We describe three AT/RTs in adults in which the diagnoses were supported by detection of 22q11.2 deletions, INI1 mutation and/or loss of INI1 protein expression. Two patients were female, ages 20 and 31 and one was male, age 45. Two tumors occurred in the sella or sellar region and one in the cerebellum. In all cases, fluorescence in situ hybridization with probes to the BCR (22q11.2) and NF2 (22q12) regions of chromosome 22 revealed single copy deletions of BCR with normal dosages of NF2 and, in all cases, immunohistochemistry demonstrated loss of INI1 protein expression. In one case, a single base pair deletion was detected in the INI1/hSNF5 gene. These molecular findings confirm the occurrence of AT/RTs in adults. Although rare, AT/RT should be considered in the differential diagnosis of poorly differentiated intracranial tumors in adults.

Recent advances in embryonal tumours of the central nervous system

INTRODUCTION

Embryonal tumours of the central nervous system (CNS) are the commonest malignant paediatric brain tumours. This group includes medulloblastomas, supratentorial primitive neuroectodermal tumours, atypical teratoid/rhabdoid tumours, ependymoblastomas, and medulloepitheliomas. Earlier, all these tumours were grouped under a broad category of primitive neuroectodermal tumours (PNETs). However, the current WHO classification (2000) separates them into individual types based on significant progress in the understanding of their distinctive clinical, pathological, molecular genetic, histogenetic, and behavioural characteristics. Furthermore, advances in histopathology and molecular genetics have shown great promise for refining risk assessment in these tumours, especially medulloblastomas, thus providing a more accurate basis for tailoring therapies to individual patients. Correlation of histological changes with genetic events has also led to a new model of medulloblastoma tumorigenesis.

REVIEW

This review presents an updated comparative profile of these tumours, highlighting the clinical and biological relevance of the recent advances.

Atypical Teratoid/Rhabdoid Tumors (ATRT): Improved Survival in Children 3 Years of Age and Older With Radiation Therapy and High-Dose Alkylator-Based Chemotherapy

Purpose

To describe clinical features, therapeutic approaches, and prognostic factors in pediatric patients with atypical teratoid/rhabdoid tumors (ATRT) treated at St Jude Children's Research Hospital (SJCRH).

Patients and Methods

Primary tumor samples from patients diagnosed with ATRT at SJCRH between July 1984 and June 2003 were identified. Pathology review included histologic, immunohistochemical analysis, and fluorescence in situ hybridization for SMARCB1 (also known as hSNF5/INI1) deletion. Clinical records of patients with pathologic confirmation of ATRT were reviewed.

Results

Thirty-seven patients were diagnosed with ATRT at SJCRH during the 19-year study interval. Six patients were excluded from this clinical review based on pathologic or clinical criteria. Of the remaining 31 patients, 22 were younger than 3 years. Posterior fossa primary lesions and metastatic disease at diagnosis were more common in younger patients with ATRT. All patients underwent surgical resection; 30 received subsequent chemotherapy. The majority of patients aged 3 years or older received postoperative craniospinal radiation. Two-year event-free (EFS) and overall survival (OS) of children aged 3 years or older (EFS, 78% + 14%; OS, 89% ± 11%) were significantly better than those for younger patients (EFS, 11% ± 6%; OS, 17% ± 8%); EFS, P = .009 and OS, P = .0001. No other clinical characteristics were predictive of survival. Three of four patients 3 years or older with progressive disease were successfully rescued with ifosfamide, carboplatin, and etoposide therapy.

Conclusion

Children presenting with ATRT before the age of 3 years have a dismal prognosis. ATRT presenting in older patients can be cured using a combination of radiation and high-dose alkylating therapy. Older patients with relapsed ATRT can have salvage treatment using ICE chemotherapy.

Central nervous system atypical teratoid/rhabdoid tumor: results of therapy in children enrolled in a registry

PURPOSE

Atypical teratoid/rhabdoid tumor (AT/RT) of the CNS is an extremely rare and aggressive tumor of early childhood. The poor outcome with conventional infant brain tumor therapy has resulted in a lack of clear treatment guidelines. A registry has been established to create an outcomes database and to facilitate biology studies for this tumor.

MATERIALS AND METHODS

A standardized data sheet was provided to treating physicians listing the reports that were to be sent to the registry for abstraction. Follow-up information was sought twice yearly.

RESULTS

Information was complete for 42 patients. Median age at diagnosis was 24 months. Nine patients (21%) had disseminated disease at diagnosis. Sixteen tumors were infratentorial; 26 were supratentorial. Twenty patients (48%) received a primary complete resection. Primary therapy included chemotherapy in all patients, radiotherapy in 13 patients (31%), stem-cell rescue in 13 patients (31%), and intrathecal chemotherapy in 16 patients (38%). Recurrent or progressive disease was reported in nine and 19 patients, respectively. Twenty-seven patients (64%) are dead of disease (3 to 62 months from diagnosis) and one patient died of toxicity. Fourteen patients (33%) show no evidence of disease (9.5 to 96 months from diagnosis). The median survival is 16.75 months and the median event-free survival is 10 months.

CONCLUSION

Aggressive therapy has prolonged the natural history in a subset of children. Prospective multi-institutional and national clinical trials designed specifically for AT/RT are needed. Enrollment onto the AT/RT registry should be continued.

Atypical teratoid/rhabdoid tumor: Cytology and differential diagnosis in adults

Atypical teratoid/rhabdoid tumors (AT/RTs) are malignant intracranial neoplasms that usually occur in the posterior fossa of children. They are characterized by cells with paranuclear rhabdoid inclusions, a mesenchymal and epithelial immunohistochemical profile, and 22q deletions with inactivation of the INI1/hSNF5 gene. Although they usually occur in young children, AT/RTs are being recognized in adults with increasing frequency. We report the cytologic features of an AT/RT from the cerebellum of a 45-year-old man and discuss the differential diagnosis in adults.

Advances in the diagnosis, molecular genetics, and treatment of pediatric embryonal CNS tumors

Embryonal central nervous system (CNS) tumors are the most common group of malignant brain tumors in children. The diagnosis and classification of tumors belonging to this family have been controversial; however, utilization of molecular genetics is helping to refine traditional histopathologic and clinical classification schemes. Currently, this group of tumors includes medulloblastomas, supratentorial primitive neuroectodermal tumors, atypical teratoid/rhabdoid tumors, ependymoblastomas, and medulloepitheliomas. While the survival of older children with nonmetastatic medulloblastomas has improved considerably within the past two decades, the outcomes for infants and for those with metastatic medulloblastomas or other high-risk embryonal CNS tumors remain poor. It is anticipated that the emerging field of molecular biology will greatly aid in the future stratification and therapy for pediatric patients with malignant embryonal tumors. In this review, recent advances in the diagnosis, molecular genetics, and treatment of the most common pediatric embryonal CNS tumors are discussed.

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.

Atypical teratoid/rhabdoid tumor of the central nervous system: report on workshop

Childhood atypical teratoid/rhabdoid tumor (AT/RT) of the central nervous system (CNS) is a recently described entity. Diagnosis is based on distinctive light microscopy and immunohistochemical findings, coupled with molecular genetic analysis. Most AT/RTs demonstrate monosomy 22 or deletions of chromosome band 22q11 with alterations of the hSNF5/INI1 gene. The tumor's incidence is still undefined, but it may comprise as high as 1 in 4 primitive CNS tumors in infants. Treatment is far from optimal, but there are occasional long-term survivors, especially among older children. Therapeutic approached have included surgery, chemotherapy, and radiotherapy. Prospective clinical trials are needed for children with AT/RTs.

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.

Atypical teratoid/rhabdoid tumors in adult patients: case report and review of the literature

Atypical teratoid/rhabdoid tumors (AT/RT) of the central nervous system are rare and extremely aggressive malignancies of early childhood. We report a case of AT/RT in an adult patient. A 30-year-old woman presented with headache, vomiting and ataxia during the second trimester of pregnancy. Magnetic resonance imaging revealed a posterior fossa mass. A gross total resection was performed. Pathological examination revealed an AT/RT. Despite the dismal prognosis the patient decided not to undergo an abortion. For this reason postoperative accelerated hyperfractionated radiotherapy was limited to the tumor region. Six months later the woman delivered a healthy baby. One week postpartum, a central nervous system recurrence localized apart from the primary lesion was treated with radiosurgery. Two months later a diffuse progression was noted. Despite a 6 week course of oral temozolomide, the tumor progressed and the patient died 11 months after diagnosis. Although survival was short, surgery and involved field radiotherapy yielded a progression-free interval of 9 months. This allowed the patient to carry pregnancy to term. Radiosurgery resulted in a complete remission of the first recurrence. Oral chemotherapy was not effective in controlling diffuse tumor spread.

"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.

Extrarenal rhabdoid tumors of soft tissue: a clinicopathologic and immunohistochemical study of 18 cases

Rhabdoid tumor is a well-accepted clincopathologic entity among childhood renal neoplasms; similar tumors have been described in extrarenal locations. We present the clinicopathologic profile and the immunohistochemical features of a series of soft tissue rhabdoid tumors. Twenty-eight cases coded as extrarenal rhabdoid tumor (ERRT), RT, possible ERRT, and "large cell sarcoma" were retrieved from the Armed Forces Institute of Pathology soft tissue registry. The tumors were reclassified according to strict criteria by light microscopy, clinical information, immunohistochemistry, and, in some cases, electron microscopy. Soft tissue rhabdoid tumor (STRT) was defined as (1) a tumor composed of noncohesive single cells, clusters, or sheets of large tumor cells with abundant glassy eosinophilic cytoplasm, an eccentric vesicular nucleus, and an extremely large nucleolus; (2) positivity for vimentin and/or cytokeratin or other epithelial markers by immunostaining; and (3) exclusion of other tumor types with rhabdoid inclusions (melanoma, other sarcomas, carcinoma). Eighteen cases met our criteria for soft tissue rhabdoid tumors. The median patient age was 13 years (range, 6 months to 56 years). Ninety-four percent of STRT cases were positive for vimentin and 59% for pan-cytokeratin. Sixty-three percent and 60% were positive for CAM 5.2 and EMA, respectively. Seventy-nine percent stained for at least one epithelial marker; 76% stained for both vimentin and epithelial markers simultaneously. Forty-two percent stained for MSA, and 14% for CEA and SMA. CD99, synaptophysin, CD57 (Leu-7), NSE, and focal S100 protein were identified in 75%, 66%, 56%, 54%, and 31% of the STRT cases, respectively. All STRT cases examined were negative for HMB-45, chromogranin, BER-EP4, desmin, myoglobin, CD34, and GFAP. Follow-up examination in 61% of the STRT patients revealed that 64% of patients died of disease within a median follow-up interval of 19 months (range, 4 months to 5 years); 82% had metastases to lung, lymph nodes, or liver; 22% had local recurrences before metastasis; and 18% were alive without known disease status (median, 5.5 years). Soft tissue rhabdoid tumor is a highly aggressive sarcoma, predominantly of childhood. Besides having nearly consistent coexpression of vimentin and epithelial markers, STRTs show positivity for multiple neural/neuroectodermal markers that overlap with those of primitive neuroectodermal tumor.