Metaplastic Meningioma Research Articles

Osseous Metaplastic Meningioma in the Thoracic Spine Mimicking Osteosarcoma

Case report. We describe a case of osseous metaplastic meningioma in the thoracic spine that pathologically mimicked osteosarcoma. As meningioma presents in many pathological forms, it is sometimes difficult to diagnose it pathologically. The patient's medical records, imaging results, and pathological findings were reviewed, as was the relevant literature. A 20-year-old woman with a 6-month history of lumbago and right sciatica was referred to our hospital because magnetic resonance imaging (MRI) showed a tumor compressing her spinal cord at the T11 vertebra level. Computed tomography (CT) showed calcification of the tumor, and the preoperative diagnosis was meningioma. Surgery was performed and the tumor was entirely removed. The tumor was very hard, and pathological findings suggested atypical meningioma with massive ossification. Some parts of the tumor seemed malignant, as spindle cells with a high nucleocytoplasmic ratio were highly concentrated, which led to the possibility of osteosarcoma. The tumor was conclusively diagnosed as osseous metaplastic meningioma based not only on the pathology, but also on CT and MRI findings and the postoperative course. As meningioma presents in many pathological forms, it is sometimes difficult to diagnose it pathologically. Results of imaging studies including CT and MRI, as well as patients' postoperative course, should be considered when making a final diagnosis of meningioma. N/A.

Clinicopathological analysis of metaplastic meningioma: report of 15 cases in Huashan Hospital.

Metaplastic meningioma is a rare subtype of benign meningiomas, classified as WHO grade I with well prognosis. Here we presented our experiences on 15 cases of metaplastic meningioma, to investigate the clinicopathological features, therapies and prognosis of these cases. 15 patients underwent surgical treatment for intracranial metaplastic meningioma between 2001 and 2010 at Neurosurgery Department of Huashan Hospital, Shanghai, China. The clinical data, radiological manifestation, treatment strategy, pathological findings and prognosis of all patients were analyzed retrospectively. Among the 15 cases (10 males and 5 females), the age ranged from 22 to 74 years old (the mean age was 50.67-year old). The clinical manifestations include headache, dizziness, seizure attack, vision decrease, and weakness of bilateral lower limbs. All the patients received surgical treatment, combined with radiotherapy in some cases. In the follow-up period, recurrence occurred in 2 cases, of which 1 patient died of other system complications. Metaplastic meningiomas are characterized by focal or widespread mesenchymal differentiation with formation of bone, cartilage, fat, and xanthomatous tissue elements. Surgical removal is the optimal therapy, and the overall prognosis is well. But recurrence may occur in some cases, thus radiotherapy is necessary for such kind of patients.

Metaplastic meningioma with pure and extensive cartilaginous transformation: A diagnostic dilemma

Meningiomas are the most common extra-axial central nervous system tumours and often discovered in the middle to late adult life and especially in women. About 85%-90% of meningiomas are benign, 5%-10% are intermediate-grade, and 3%-5% are malignant. Metaplastic meningioma is a rare subtype of WHO Grade I meningioma histologically characterized by the presence of mesenchymal components. The presence of pure and extensive cartilaginous differentiation in meningiomas is extremely rare and remains a diagnostic dilemma. We report, perhaps the first case of this entity in a 52-year-old woman and discuss the pathogenesis, the imaging features and the histopathologicals data.

Totally Ossified Metaplastic Spinal Meningioma

A 61-year-old woman with a very rare case of totally ossified large thoracic spinal metaplastic meningioma, showing progressing myelopathy is presented. Computed tomographic images showed a large totally ossfied intradural round mass occupying the spinal canal on T9-10 level. Magnetic resonance imaging revealed a large T9-10 intradural extramedullary mass that was hypointense to spinal cord on T1- and T2-weighted sequences, partial enhancement was apparent after Gadolinium administration. The spinal cord was severely compressed and displaced toward the right at the level of T9-10. Surgical removal of the tumor was successfully accomplished via the posterior midline approach and the histological diagnosis verified an ossified metaplastic meningioma. The clinical neurological symptoms of patient were improved postoperatively. In this article we discuss the surgical and pathological aspects of rare case of spinal totally ossified metaplastic meningioma.

Myxoid meningioma: a rare metaplastic meningioma variant in a patient presenting with intratumoral hemorrhage

Myxoid (metaplastic) meningioma is a rare WHO Grade I meningioma subtype arising from the leptomeninges. It has unique Alcian blue stromal staining and distinctive cellular interdigitations, junctional complexes, and nucleolar pseudoinclusions on ultrastructural pathology that help to distinguish it from other meningioma variants. The authors describe the case of a rare left middle fossa, extraaxial myxoid meningioma in a 50-year-old woman to emphasize the important histological characteristics and observations essential for making a precise diagnosis. To their knowledge this is the seventh reported case of a myxoid meningioma in the literature and the sixth case in an adult; however, it is the first reported instance of myxoid meningioma in a patient presenting with intratumoral hemorrhage.

Intracerebral metaplastic meningioma with prominent ossification and extensive calcification

We present a patient (male 26 years) with a short history of recurrent seizures induced by a largely intracerebrally located frontal lobe meningioma. The tumor displayed a heretofore unpublished combination of extensive metaplastic bone formation and prominent non-psammomatous calcifications with focal chicken-wire pattern.

Ossified Metaplastic Meningioma with Intratumoral Hemorrhage

Ossified Metaplastic Meningioma with Intratumoral Hemorrhage

Intraventricular metaplastic meningioma in a child: case report and review of the literature

Childhood meningiomas are rare and display important differences from adult forms. We report the first case of an intraventricular metaplastic meningioma arising in a child. A 7-year-old female underwent resection of an enhancing tumor arising within the left lateral ventricle. It was composed of monomorphic cells embedded within an abundant myxoid stroma. The cells demonstrated epithelial membrane antigen and vimentin immunoreactivity. Ultrastructural analysis demonstrated intermediate filaments, complex intercellular interdigitations and desmosomes, and a diagnosis of myxoid (metaplastic) meningioma was rendered. This case reflects the higher incidence of intraventricular meningiomas in childhood and greater incidence of intraventricular meningiomas in the left lateral ventricle. Recognition of the grade I myxoid meningioma in this case is paramount since chordoid meningiomas, which share similar histologic features, are of a higher grade and worse prognosis.

Surgical resection without dural reconstruction of a lumbar meningioma in an elderly woman

Meningiomas of the spine occur in the thoracic spine in approximately 80%, followed in frequency by the cervical and lumbar regions. The treatment of spinal meningiomas is complete surgical resection. As intraspinal meningiomas are almost always adherent to the dura, extensive dural resection or diathermic treatment of the dural attachment is usually performed to prevent tumor recurrence. The authors present the case of lumbar spinal meningioma in 82-year-old woman. Successful resection with preservation of the dura mater using the technique of Saito et al. (Spine 26:1805-1808, 2001) is described: After lumbar laminectomy a small incision was made in the surface of the spinal dura. The dura mater was separated into its inner and outer layers, and the tumor was resected with inner layer alone, preserving the outer layer. The outer layer is simply closed to achieve a watertight seal. The pathologic diagnosis was metaplastic (osseous) meningioma. Almost full recovery of the neurologic deficit was attained. Neither complication nor tumor recurrence has occurred in the 5 years since surgery. Dural preservation during surgical resection of spinal meningioma obviates the need for dural reconstruction and should reduce surgical morbidity. However, the patient should be followed long-term to watch for recurrence.

A case of metaplastic meningioma with extensive xanthomatous change

We report a case of metaplastic meningioma with extensive xanthomatous change occurring in a 61-year-old woman. Magnetic resonance imaging demonstrated a well-demarcated, dura-based mass measuring 7 cm in maximal diameter in the right occipital to parietal area. Under a clinical diagnosis of meningioma, right parietal craniotomy was performed. Histologically, the tumor showed extensive xanthomatous change together with the common features of meningothelial meningioma. Tumor cells showed diffuse xanthomatous change in various quantities, and xanthomatous tumor cells frequently showed a gradual transition to the non-xanthomatous counterpart. The xanthomatous tumor cells showed immunopositivity for epithelial membrane antigen (EMA), vimentin, fatty acid synthase and several histiocytic markers (CD68, Ki-M1p, MAC387, lysozyme, alpha 1-antitrypsin and alpha 1-antichymotrypsin). In addition, there was patchy infiltration of foamy macrophages. Since these histiocytes did not show immunopositivity for EMA, these cells were distinguished from the xanthomatous tumor cells. These two types of xanthomatous changes comprised approximately two-thirds of the whole tumor tissue. Any atypical features such as necrosis, frequent mitotic figures or brain parenchymal invasion were not observed. We diagnosed this case as xanthomatous meningioma, WHO grade I.

Periosteal osteoblastoma of the calvaria mimicking a meningioma

While osteoblastoma of the cranial vault is rare, the periosteal form of the tumor is highly unusual, with only one case reported in the English literature. We report on a 24-year-old woman presenting with headache and tinnitus. Magnetic resonance imaging of the brain showed an extra-axial temporal mass with findings that were suggestive of a meningioma. The mass was excised completely, and histological examination revealed a periosteal osteoblastoma arising from the inner surface of the temporal bone and adhering to the dura. The tumor was strongly positive for epithelial membrane antigen, a feature not previously described in osteoblastoma, and one that could lead to a mistaken diagnosis of metaplastic meningioma in a limited sample. A detailed literature review of 40 other reported cases of calvarial osteoblastoma is presented. Apart from being slightly more common in females, calvarial osteoblastoma is similar in all other respects to that arising at conventional skeletal sites. Accurate histological diagnosis of a calvarial osteoblastoma requires adequate sampling of the tumor, including its interface with adjacent structures. Correlation with the radiological findings is crucial for the diagnosis in most cases; however, it is not helpful in differentiating the rare intracranial periosteal variant from a meningioma.

Lipomatous meningioma: report of 2 cases and review of the literature

Background Lipomatous meningioma is a rare but, most of the time, benign tumor. Its pathogenesis is still debated: it is usually considered to be part of the metaplastic meningioma, but several authors recently suggested that fat accumulation inside the tumor was related to metabolic disorders of the meningothelial cells. Cases Description We report 2 cases of lipomatous meningioma. Both patients were women older than 60 years. One patient suffered from headache and seizures, the other one presented with behavioral disturbance. Radiological features depended on the amount of fat accumulation within the tumor. Surgical treatment allowed complete resection in both cases without any complications. Both meningiomas were of transitional-type and were apparently composed of 2 populations of cells: meningothelial cells and lipid-laden cells resembling mature adipocytes. Immunohistochemical study showed that lipid-laden cells expressed EMA, CD99, and progesteron receptor, favoring a meningothelial differentiation rather than an adipocytic lineage. Conclusion Our study strongly suggests that lipomatous meningioma results from an accumulation of lipid inside meningothelial cells rather than a true metaplasia.

NF2 Mutations in Secretory and Other Rare Variants of Meningiomas

The WHO classification defines different histological variants of meningiomas. Mutations of the tumor suppressor gene NF2 on 22q have been described in 30% to 60 % of sporadic meningiomas. However, the vast majority of the meningiomas that have been subject to NF2 analysis belong to the most frequent variants like transitional, fibroblastic and meningothelial meningiomas. Within these subtypes, transitional and fibroblastic meningiomas harbor significantly more NF2 mutations than meningothelial meningiomas, indicating molecular subsets of these tumors. To determine whether rare meningioma variants carry NF2 mutations we analyzed 80 tumors. NF2 mutations were detected in 5 (36%) of 14 psammomatous, 1 (11%) of 9 angiomatous, 2 (22%) of 9 clear cell, 1 (33%) of 3 chordoid and 1 (100%) of 1 papillary meningioma. In the single papillary meningioma, 2 different NF2 mutations were observed. No NF2 mutations were found in 33 secretory, 7 microcystic, 2 lymphoplasmacyte-rich, one rhabdoid and one metaplastic meningioma. In the control group of 25 fibroblastic meningiomas, 11 cases were identified to carry an NF2 mutation. These results support the concept of different molecular subgroups of meningiomas which overlap with histological variants.

Méningiome lipomateux: À propos de deux cas

Lipomatous meningiomas are rarely encountered and are included in the World Health Organization's (WHO) group of metaplastic meningiomas. We report two cases of these tumors. The presenting symptoms were headaches in one case and seizure in the other. Radiologically, these tumors were extra-axial and unique. One tumor displayed fat accumulation, while the other had the appearance of a conventional meningioma. Microscopically, these tumors corresponded to meningothelial and transitional meningiomas containing a variable proportion of adipose tissue composed of mature adipocytes or lipoblasts. Fat content was high in one case and moderate in the other, thus explaining the radiological findings. Expression of epithelial membrane antigen and progesterone receptors was present in meningothelial, adipocyte-like, and lipoblast-like cells. These immunohistochemical results suggest that lipid accumulation in meningioma should be considered a transformation of meningothelial cells rather than a true metaplasia.

A Rare Case of Periosteal Osteoblastoma Located in the Frontal Cranial Bone

Periosteal osteoblastoma is an extremely rare bone-forming neoplasm located on the surface of cortical bone. Of the fewer than 30 cases of periosteal osteoblastomas found in the literature, 2 have been reported to be located in cranial bone, and these have not been documented in detail with clinical history, radiographic findings, macroscopic features, and microscopic findings. Although the differential diagnoses of periosteal lesions include parosteal and periosteal osteosarcoma, periosteal chondroma and chondrosarcoma, osteochondroma, osteoid osteoma, periostitis ossificans, and myositis ossificans, an important differential diagnosis both radiologically and pathologically of such a lesion in the cranium is meningioma. We report an unusual case of periosteal osteoblastoma located in the frontal cranial bone that was radiologically consistent with a meningioma. The differential diagnosis of metaplastic meningioma with differentiation toward bone is discussed.