Lipomatous Meningioma

Abstract

We report 18 cases of lipomatous meningioma occurring in patients aged 14 to 79, most being females (72%). Sixteen were supratentorial and 2 involved the spinal meninges. Follow-up ranged from 1 to 120 months. Fifteen patients were cured with surgery alone and 3 (17%) experienced a recurrence at 7, 8 and 24 months. Of these, one died with disease 4 years after resection of the primary lesion. Histologically, 12 tumors were meningothelial, 3 transitional, 2 showed myxoid stromal changes and 1 was microcystic. The 2 spinal tumors were atypical. The proportion of fatty cells ranged from 10 to 90%. These resembled mature adipocytes or less commonly lipoblasts. Xanthomatous meningothelial cells were also noted in 6 tumors (30%). Both conventional meningothelial as well as lipid-laden cells exhibited epithelial membrane antigen immunoreactivity. In addition, occasional cells resembling mature adipocytes showed reactivity for S-100 protein. Ultrastructurally, lipidization of neoplastic cells varied from intracytoplasmic lipid droplets to a single massive globule. Moreover, lipid-laden meningothelial cells featured interdigitating cell membranes and well-formed desmosomes. Lipid droplets were not membrane-bound. In that metaplasia denotes differentiation of one mature cell type to another, lipid accumulation in meningiomas cannot be considered true metaplasia since their lipid-laden cells retain the immunophenotype and ultrastructural features of meningothelium. We suggest that this distinctive subset of meningiomas be termed "lipidized meningiomas" rather than being included in the metaplastic category.

Lipomatous Metaplasia after Severe and Chronic Cutaneous Inflammation

“…Lipomatous metaplasia is regularly seen in scars of the left ventricle after an ischemic heart disease [2] as well as in endogenous [3] and exogenous [4] glands and a rare subpopulation of meningiomas [5], but it is not generally associated with chronic inflammation. In the skin, lipomatous metaplasia is very uncommon.…”

Lipomatous Change in Uveal Melanoma: Histopathological, Immunohistochemical and Cytogenetic Analysis

“…We therefore prefer to refer to this phenomenon as lipomatous change. Other neuroectodermal tumors that may contain adipocytes include cutaneous melanocytic nevi [7], schwannoma [8], neurofibroma [9], perineurioma [10], meningioma [11] and adrenal adenoma [12]. In most cases as well as in the current case, the cells retain at least some of the characteristics of their original lineage, which would argue against true metaplasia.…”

Lipomatous meningioma: Case report and review of the literature

“…Though initially thought to involve the metaplasia of meningothelial cells to adipocytes, [7] several authors have attributed the alteration to fat accumulation due to disrupted metabolism within meningothelial cells. [1, 8] The cells are typically positive for histologic markers including epithelial membrane antigen, vimentin and CD68. The hallmark finding however is the presence of adipocyte-like cells, which were noted in the histopathologic specimen from our patient.…”

“…[1] The mean age for lipomatous meningioma presentation is 50 years of age with a range from 22 to 74 years reported in the literature. [2] These tumors are a subgroup of a broader class termed “metaplastic meningiomas” that has been proposed by the World Health Organization.…”

“…[3] It is a variant, which contains mesenchymal components including osseuous, cartilaginous, lipomatous, myxoid and xanthomatous tissue. [1, 3] Characteristic of lipomatous meningiomas are intratumoral fat accumulations, which are best appreciated on computerized tomographic (CT) as hypodense and on T1-weighted magnetic resonance imaging (MRI) as hyperintense lesions. [4] Definitive diagnosis requires histopathologic evaluation and cannot be based on imaging findings alone.…”