Classification for Craniopharyngioma and Histopathological Aspect


Fig. 3.1

Pathological manifestation of aCP (ac). (1) Whorl-like cells, (2) stellate reticulum, (3) palisade-like cells, (4) wet keratin, (5) calcification, (6) cysts



3.3 Papillary Craniopharyngioma (pCP)


The typical pathological feature of pCP is the stratified papillary squamous epithelium. At the center of the squamous epithelium, the fibrous vascular core is visible. The cells around the fiber core are called the basal cells. In the tumor parenchyma, new blood vessels of different sizes and densities can be seen. In pCP, calcification and wet keratin are rare, and cystic cavities are still visible in some tumor parenchyma (Fig. 3.2).

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Fig. 3.2

Typical pathological performance of pCP (a, b). (1) Basal cells


3.4 The Four Segments of Pituitary Stalk


Previously, we found that the suprasellar arachnoid arising from the basement membrane of the arachnoid envelops the pituitary stalk to form an arachnoidal sleeve (ASPS). The pituitary stalk was divided into four segments in accordance with the folds of the ASPS, namely, the infradiaphragmatic, extra-arachnoidal, intra-arachnoidal, and subarachnoidal segments (Fig. 3.3).

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Fig. 3.3

The four segments of pituitary stalk and membrane structures in sellar area (af). (1) Basal arachnoid membrane (BAM), (2) arachnoid trabecula, (3) pituitary stalk, (4) neurohypophysis, (5) pars distalis, (6) diaphragma sellae, (7) infradiaphragmatic segment, (8) extra-arachnoidal segment, (9) intra-arachnoidal segment, (10) subarachnoidal segment, (11) pars tuberalis, (12) median eminence, (13) infundibular, (14) intermediate lobe


3.5 QST Typing System for Craniopharyngioma


On the basis of the tumor origin and on the presence of an arachnoid envelope around the pituitary stalk (ASPS), we established a QST typing system for craniopharyngioma (Fig. 3.4). Type Q tumors originate below the diaphragma, and the pituitary gland is therefore most likely to be involved. Type S tumors originate from pars tuberalis adherent to the extra-arachnoidal and intra-arachnoidal segments of the pituitary stalk, and this type of tumor is more likely to involve the pituitary stalk. The pituitary gland and the third ventricle floor remain almost normal or may be slightly displaced by the tumor. Type T tumors originate at the top of pars tuberalis. These tumors are located in the subarachnoid space, outside the pia mater, and usually occupy the third ventricle cavity, involving the third ventricle floor and the proximal pituitary stalk; the distal pituitary stalk and pituitary gland are usually normal.

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Fig. 3.4

Schematic of QST classification for craniopharyngioma. (a, b) Type Q tumors (T) originate beneath the diaphragma sellae. The adenohypophysis (AP) and the neurohypophysis (NP) were compressed by the tumor. The diaphragm (while arrow head) covers the tumor and was often pushed upward by the tumor. The tumor and the nerve layer of the third ventricle floor are separated by a multilayered membrane structure. Even when the tumor extends suprasellarly, the nerve layer of the third ventricle floor is not typically involved. (c, d) Type S tumors originate from Rathke’s pouch precursor cells that remain in pars tuberalis adherent to the extra-arachnoidal and intra-arachnoidal segments of the pituitary stalk. The pituitary stalk (white arrow head) was most likely involved by the tumor. The pituitary gland (red arrow head) and the third ventricle floor (yellow arrow head) were often normal. The ASPS or an inner layer of arachnoid can be seen between the tumor and the nerve layer of the third ventricle floor, which makes surgical separation fairly simple. The diaphragma sellae prevent the tumor from growing downward into the pituitary fossa. (e, f) Type T tumors originate from Rathke’s pouch precursor cells that remain in the top of pars tuberalis. Type T tumors are located beneath the basal arachnoid membrane and outside the pia mater. The lower part of the pituitary stalk (PS) and the pituitary gland (red arrow) was often normal. The third ventricle floor could be not appeared in MRI. Some type T tumors can grow through the ASPS or break through the inner arachnoid layer near the pars tuberalis, subsequently growing into the subarachnoid space

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Mar 25, 2020 | Posted by in NEUROSURGERY | Comments Off on Classification for Craniopharyngioma and Histopathological Aspect
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