Malignant meningioma with adenocarcinoma‐like metaplasia: Demonstration of intestinal phenotype

Abstract

Meningiomas show a diverse histopathologic appearance, often referred to as metaplastic changes; however, adenocarcinoma-like metaplasia is an extremely rare condition. Here, we present a novel case. A dura-based bulky mass located in the right frontotemporal region was identified radiologically in an 83-year-old woman. The tumor, yellow to ash-gray in color, was subtotally removed. Histopathological examination revealed robust adenocarcinoma-like structures within a conventional meningothelial neoplasm. Meningioma elements showed a WHO grade I to III histology. Morphological and immunophenotypic transition between meningothelial and columnar epithelial cells was confirmed on detailed observation. It was of note that the adenocarcinomatous components shared an immunophenotype with intestinal epithelium, expressing CDX2, MUC2 and cytokeratin 20. The present case could be differentiated from secretory meningioma based on distinct cellular atypia, lack of intracytoplasmic lumina and pseudosammoma bodies, and the intact status of the KLF4 gene. In addition, the morphological and immunophenotypic transition excluded the possibility of metastatic carcinoma within meningioma. This is the first reported case of meningioma with adenocarcinoma-like metaplasia harboring an intestinal immunophenotype.

A rare intracranial tumor consisting of malignant anaplastic and papillary meningioma subtypes

“…Intracranial meningiomas with intratumoral heterogeneity (adenocarcinoma-like metaplasia) have also been reported in the literature. [ 12 17 ] These cases have shown a WHO Grade I–III histology intermingled heterogeneously within the same mass lesion. [ 12 17 ] In these reported cases, the radiologic appearance of the tumors differed significantly from our case in that they were heterogeneous lesions without a clearly demarcated interface.…”

“…[ 12 17 ] These cases have shown a WHO Grade I–III histology intermingled heterogeneously within the same mass lesion. [ 12 17 ] In these reported cases, the radiologic appearance of the tumors differed significantly from our case in that they were heterogeneous lesions without a clearly demarcated interface. In our case, an interface between what appeared to be two discrete lesions was evident and was reported by the radiologist.…”

“…Solitary intracranial tumors with intratumoral heterogeneity consisting of varying meningioma subtypes are a known reported pathologic entity. [ 12 17 ] Collision tumors are rarer entities that consist of well-demarcated, discrete tumors of differing histopathology that occur in direct contact within the same anatomic location. These tumors are rare, especially in the brain, with less 30 cases of collision tumors between intrinsic brain tumors reported in the literature since 1970.…”