glioma is a rare low-grade tumor described for the first time in 1998 as a distinct clinical-pathological entity and classified as a WHO grade II glioma (1).
Other lesions that can involve the hypothalamus are chordoid
glioma, pituitary mass, metastasis, and meningioma.
glioma of the third ventricle###*###Haemangioblastoma###*
WHO classification of meningiomas (adapted after Louis et al., 2016)  Meningioma WHO grade Histological type Meningothelial meningioma Fibrous meningioma Transitional meningioma WHO grade I Psammomatous meningioma Meningioma Angiomatous meningioma Microcystic meningioma Secretory meningioma Lymphoplasmacyte-rich meningioma Metaplastic meningioma WHO grade II Chordoid
meningioma Meningioma Clear cell meningioma (intracranial) Atypical meningioma WHO grade III Papillary meningioma Meningioma Rabdoid meningioma Anaplastic (malignant) meningioma Table 2.
(1) Grade II meningiomas, deemed atypical meningiomas include those with a clear cell or chordoid
histologic pattern as well as any lesion that displays brain invasion or [greater than or equal to] 4 mitoses per high power field (hpf).
Grade II meningiomas (atypical) are defined by one or more of the following four criteria: (1) chordoid
or clear cell histologic subtype, (2) 4 to 19 mitoses per ten high-power field (HPFs), (3) brain infiltration, and (4) 3 or more of the following five histologic features: small cell change, increased cellularity, prominent nucleoli, sheet-like growth, or necrosis.
We identified 4 well-described UCa variants, including those with rhabdoid (9 of 28; 32%; Figure 2, B), poorly differentiated squamous (8 of 28; 29%; Figure 2, C), chordoid
(3 of 28; 11%; Figure 2, D), and lymphoepithelioma-like (1 of 28; 4%) features.
meningiomas often contain regions that are histologically similar to chordoma, with cords or trabeculae of eosinophilic, vacuolated cells in a background of abundant mucoid matrix background.
(5,11,12) Tumours with (1) predominantly chordoid
pattern and small chondroid foci.
meningioma arising in the pineal region: a case report.
Owing to its histological aspect, chordoma needs to be differentiated from many other tumors, including chondrosarcoma, metastatic adenocarcinoma, clear cell renal cell carcinoma (CCRCC), or central nervous system (CNS) neoplasias with a chordoid
Rare pathological types, such as rhabdoid, osteoblastic and chordoid
types have been described (2,24,53).