Objective: Meningiomas involving the pineal region are rare. Herein we describe two cases of chordoid meningioma with histologic evidence of pineal gland infiltration.
Materials and methods: Clinical histories were abstracted from chart review and consultation letters. HE-stained slides were reviewed in both cases. Selected immunohistochemical stains were performed.
Results: the patients included a 44-year-old male and a 37-year-old female who presented with symptoms of intracranial tumor referable to the pineal region. On magnetic resonance imaging (MRI), both lesions demonstrated heterogeneous contrast enhancement. Histologically, the tumors were characterized by strands and cords ofmeningothelial cells arranged in a mucinous stroma. In addition, obvious meningothelial cytology as well as focal osseous metaplasia (Case 1), and transitional histology (Case 2) were also noted. Tumor cells demonstrated EMA and focal S100 protein immunoreactivity, but lacked cytokeratin AE1/AE3 and glial fibrillary acidic protein (GFAP) staining. Synaptophysin and neurofilament protein highlighted the overrun pineal gland parenchyma. MIB1-proliferative index was 8.4 and 20.1%, respectively.
Conclusions: Chordoid meningioma, although rare, may occur in the pineal region. The differential diagnosis of this meningioma subtype in this location is discussed.