Lipomatous metaplasia occurring within meningiomas--two case reports.

Lipomatous meningiomas have recently been described as rare well defined variants of meningiomas characterized by meningothelial cells which undergo a metaplasia to adipocytes. Presence of intratumoral fat can sometimes cause confusion in preoperative radiological diagnosis. We report two such histologically unusual cases of meningiomas with significant adipose tissue metaplasia.

Meningiomas and hormonal receptors: immunohistochemical study in typical and non-typical tumors

The authors assessed 116 cases of meningiomas classified as typical, atypical and anaplastic and they used an immunohistochemical technique for estrogen and progesterone receptors attempting to determine if there is any difference between typical and non-typical tumors in relation to hormone receptors. The immunohistochemical technique to estrogen receptors was negative in all meningiomas studied. Progesterone receptors were detected in 58.3 percent of typical, and in 48.2 percent of non-typical meningiomas. This difference was not statistically significant. However, individually considering the criteria used for selection of non-typical tumours, those that concurrently displayed brain invasion and increased mitotic activity or necrosis, as well as the summation of those three features, were predominantly negative for progesterone receptors (respectively p=0.038; p=0.001; and p=0.044). The authors conclude that estrogen receptors were not present in meningiomas; that progesterone receptors in isolation are not enough to predict a higher tumoral malignancy but can be useful associated with other histological features.