Lipidized or lipomatous meningioma, which is more appropriate? A case report

Revisiting Lipomatous Meningioma: A Case Report and Review of an Unusual Entity

Lipomatous meningioma is a very rare subtype of metaplastic meningioma. It is defined by the presence of adipocytic-like cells, which are thought to result from lipid accumulation in meningothelial cells or true metaplastic change. We report a case of a lipomatous meningioma arising in a female patient complaining of recent seizures. Imaging studies revealed a 4-cm dural-based mass, with severe perilesional edema. Histologically, the tumor was composed of meningothelial whorls intermixed with adipocytic-like cells. No atypical criteria or brain invasion were found. The 2 components have differences in progesterone receptor expression and Ki-67 labeling, which may suggest that adipocytic-like cells may represent some quiescent form of meningothelial neoplastic cells, characterized by metabolic abnormalities, leading to lipid accumulation and very low proliferative activity. Lipomatous meningioma should also be kept in mind when considering the differential diagnosis of dural lesions with vasogenic edema in the absence of brain invasion.

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

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Unclassified glioneuronal tumor with advanced lipidization

Lipidization is observed only occasionally in primary neuroectodermal tumors of the central nervous system. It may reflect lipomatous transformation of tumor cells into xanthomatous and/or adipocyte-like cells. We report a unique case of mixed glioneuronal tumor with marked lipomatous changes in a young patient with intractable epilepsy. MRI revealed a well-circumscribed lesion in the right temporal lobe. Histopathological findings showed the pleomorphic tumor with numerous cells containing large lipid droplets, resembling mature adipocytes, that were arranged in clusters or scattered within the neoplastic tissue. The tumor was composed of both glial and neuronal elements. Some tumor cells displayed features intermediate between glial and neuronal cells. The reticulin fibers were limited to blood vessels. Mitotic figures, vascular proliferation, and necrosis were absent, and MIB-1 labeling index was less than 1%. Diffuse immunoreactivity for GFAP and S100-protein was observed. In some heavily lipidized cells, the lipid droplets were surrounded by a cytoplasmic rim of GFAP immunoreactivity. Numerous cells exhibited immunostaining for NSE and synaptophysin. This is the first documented case of glioneuronal tumor with extensive lipomatous transformation, which might be considered as a heavily lipidized unclassified pleomorphic glioneuronal tumor or a variant of lipoganglioglioma with marked pleomorphism and severe lipidization.

Lipomatous meningioma with concomitant acute subdural hematoma--case report--

A 55-year-old man presented with a rare lipomatous meningioma associated with acute subdural hematoma manifesting as sudden onset of severe headache, but no neurological deficit. No evidence of trauma or underlying predisposition to hemorrhage was seen. Fluid-attenuated inversion-recovery magnetic resonance imaging showed a thin hyperintense area in the right temporal convexity, and an extra-axial mass appearing as mixed hypointensity and hyperintensity. Two weeks later, right temporal craniotomy was performed and the tumor was totally resected with the attached dura. The hematoma was localized at the inferior margin of the mass and connected directly with the tumor. Histological examination of the resected specimen revealed typical meningothelial meningioma admixed with mature adipose tissue. Longstanding intratumoral congestion probably caused hyaline deposition in the tissue, leading to vessel rupture.

Lipomatous meningioma

We present a case of intracranial lipomatous meningioma in the parietal convexity in a 64-year-old woman. The mass showed low density on computed tomography, was hyper-intense on T1-weighted magnetic resonance images, and had decreased intensity upon imaging with fat-suppressed sequences. Gross total removal of the tumor was performed. Histopathologically, the tumor was a meningioma with mixed transitional and lipomatous patterns. Immunohistochemically, the meningothelial foci were positive for epithelial membrane antigen (EMA) and vimentin, and negative for S-100 protein. The lipomatous foci were positive for EMA, vimentin, and S-100 protein. The Ki-67 index values of the meningothelial and lipomatous foci were 1.0% and 1.8%, respectively. We review previous reports of lipomatous meningioma and discuss its clinical presentations and pathology.

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.

Atypical imaging appearances of intracranial meningiomas

Meningiomas are the commonest primary, non-glial intracranial tumours. The diagnosis is often correctly predicted from characteristic imaging appearances. This paper presents some examples of atypical imaging appearances that may cause diagnostic confusion.