Songtao Qi

Anatomic relations of the arachnoidea around the pituitary stalk: relevance for surgical removal of craniopharyngiomas

PurposeThe growth pattern of craniopharyngiomas (CP) is yet to be understood due to challenges arising from the diversity of morphological features that exist. This in turn has had implications on the development of safe surgical strategies for management of these lesions. The aim of this study is to propose a morphological classification of CP based on their tumor–membrane relationship. It is hoped that this will contribute to better understanding of CP morphology and prediction of the intraoperative classification.MethodsHistological techniques were used to study eight fetuses. Following Masson staining, the membranes around the pituitary stalk were observed under microscope. Pre-operative MRI and intraoperative images of 195 patients with CP were also analyzed.FindingsThe arachnoidal sleeve around the pituitary stalk (ASPS) was noted to be comprised of a compact fibrous component and a related loose trabecular component. The pituitary stalk was divided into four segments in accordance with the folds of the ASPS. Correspondingly, the growth of CPs was divided into four basic patterns—infra-diaphragmatic (ID), extra-arachnoidal (EA), intra-arachnoidal (IA) and sub-arachnoidal (SA) growth. The IA growth pattern can be further subdivided into two subtypes—namely, IA1 (with tumor growing within the fibrous component of the ASPS) and IA2 (with tumor growing within the trabecular component). This method of topographical division can be used to understand the growth of CP—infra-diaphragmatic CP show growth pattern ID or ID together with EA. Suprasellar CP can show an extra-ventricular growth pattern (EA or IA2), an extra- and intra-ventricular (IA2 + SA) growth pattern, a trans-infundibular growth pattern (ID + IA1 + SA) and an infundibulo-tuberal growth pattern (SA or SA + IA1). There is a statistically significant difference between CP growth patterns in children and adults. A predominance of ID growth is noted in children while adults tend to show a pattern of predominantly Extra-ventricular (EV) growth.ConclusionOur proposed classification details the relationship of the surrounding structures to CPs and purports to predict and identify the intraoperative anatomical stratification. It also attempts to help predict the growth patterns of these tumors. A knowledge of the intimate relations of the tumor and its key surrounding structures allows for safe surgical removal.

Intraventricular craniopharyngioma: morphological analysis and outcome evaluation of 17 cases

PurposeThere is still some confusion with regard to the tumor–third ventricle floor (3rd VF) relationship of craniopharyngiomas located exclusively within the third ventricle. This study aims to provide some evidence to clarify the growth pattern of intraventricular craniopharyngiomas (IVC), and to summarize the surgical strategy and outcome.MethodsSeventeen cases of IVC were reviewed retrospectively in relation to preoperative imaging, clinical presentation, intraoperative findings, tumor pathology, and surgical outcome. The tumor–3rd VF relationship and the tumors stratification were analyzed based on intraoperative inspection and histology.FindingsVariable adherence patterns of IVC to the 3rd VF were found, which were classified as (a) purely IVC with pedicle attachment to 3rd VF (two cases), (b) intra-3rd VF tumors with wide-based attachment but a dissectible tumor boundary (seven cases), and (c) intra-3rd VF tumors with an undissectible wide, tight attachment (eight cases). Histological analysis revealed that both of the two cases with growth pattern “a” intruded into the third ventricular cavity without a covering layer of neural tissue (which only exists in the squamous-papillary subtype). Tumors with growth pattern “b” and “c,” in contrast, were noted to have a thin layer of neural tissue. This occurred in both subtypes (11 adamantinomatous, 4 papillary). Total removal was accomplished in all tumors demonstrating growth pattern “a” and “b.” There was also better preservation of the 3rd VF and consequently a better outcome. On the other hand, total removal was only achieved in 50% of tumors showing growth pattern “c” including one mortality. No recurrence has been encountered in patients whose tumors were totally removed.ConclusionVariable adherence patterns and tumor subtypes were observed in IVCs, which were correlated to the tumor pathology, resectability, and subsequent prognosis.

Pneumatization of the sphenoid sinus in Chinese: the differences from Caucasian and its application in the extended transsphenoidal approach.

In recent years, the transsphenoidal approach has been extensively used surgically to treat parasellar, suprasellar, clival, and even petrous lesions. Extended pneumatization of the sphenoid sinus (SS) is considered an indispensable element for the extended transsphenoidal (ETS) approach. Because most anatomical studies of the ETS approach use Caucasian subjects, the present study aims to clarify the pneumatic extension types in Chinese individuals as well as any differences from those in Caucasians and analyze these differences with respect to the application of the ETS approach. A total of 200 computed tomography (CT) images of SSs and 18 adult cadaveric heads were selected for observation and measurement. The conchal, presellar, and sellar types comprised 6, 28.5, and 65.5% of subjects, respectively; according to the extra extension, the prevalence of the lateral, clival, lesser wing, and combined extension sinus types was 11.4, 21.4, 0.8, and 48.1% of subjects, respectively. The percentages of pneumatization of the anterior and posterior clinoid processes, pterygoid process, and optic strut were 5.0, 1.0, 22.3, and 7.0%, respectively. Onodi cells were observed in 61.1% of the sides of the cadaveric heads, including 30.6% with good pneumatization with identifiable optical or ICA bulges. These features were related to poor lateral and clival gasification in Chinese compared with Caucasians, which might make extended surgery more dangerous. However, the anterior pneumatization, especially the higher presentation of Onodi cells, ensures that the anterior ETS approach can be performed safely in Chinese patients. In general, measurements showing smaller sinus volumes and thicker bones with identifiable bone landmarks that are hard to find compared with those in Caucasians suggest increased surgical risks in the Chinese population. In this situation, carefully analysis of presurgical CT and magnetic resonance imaging scans is important. Furthermore, in the ETS approach, the use of stricter intraoperative technological devices such as neuronavigation and ultrasound Doppler is advisable.

Epithelial–mesenchymal transition and clinicopathological correlation in craniopharyngioma

Qi S‐T, Zhou J, Pan J, Zhang C, Silky C & Yan X‐R (2012) Histopathology61, 711–725 
Epithelial–mesenchymal transition and clinicopathological correlation in craniopharyngioma

Anatomical Study of the Arachnoid Envelope Over the Pineal Region

BACKGROUND The distribution of the arachnoid membrane and its relationship with the neurovascular structures in the pineal region are still not fully understood. OBJECTIVE Because the arachnoid membrane has an intimate relationship with the neurovascular structures in the pineal region and it will always be encountered surgically, we attempted to clarify the formation and distribution of the arachnoid envelope over the pineal region (AEPG). METHODS The formation and distribution of the AEPG and its relationship with the neurovascular structures in the pineal region were examined by anatomic dissection in 20 adult cadaveric formalin-fixed heads. RESULTS The supratentorial and infratentorial outer arachnoid membranes converged at the tentorial apex and then embraced and ran forward along the vein of Galen to form the AEPG. The AEPG could be divided into 2 parts. Typically, the posterior part of the AEPG enveloped the vein of Galen and the terminal segments of its tributaries, and the anterior part of the AEPG enveloped the suprapineal recess, the pineal gland, and the distal segment of the internal cerebral veins. The compartment demarcated by the AEPG did not communicate with the adjacent subarachnoid cisterns or space. CONCLUSION Previous knowledge about the AEPG, as well as the superior boundary and the contents of the quadrigeminal cistern, needs to be revised. The arrangement and individual variation of AEPG are important for a better understanding of the various growth patterns of the pineal tumors and the relationship between the tumor and the neurovascular structures in the pineal region.

The distribution of arachnoid membrane within the velum interpositum

BackgroundThere is as yet little knowledge as to the arachnoid architecture within the velum interpositum. The aim of this study was to clarify the distribution of the arachnoid membrane within the velum interpositum and its relationship with the arachnoid envelope over the pineal region.MethodsIn seven adult cadaver heads, histological sections of the third ventricle roof, stained with Masson’s trichrome stains, were studied under light microscopy.ResultsWithin the velum interpositum, there are two arachnoid layers. The dorsal layer of arachnoid membrane envelops the internal cerebral veins and fixes them to the surrounding tela choroidea as well as the ventral arachnoid layer. The ventral layer of arachnoid membrane is a direct anterior extension of the arachnoid envelope over the pineal region and covers the midline inferior layer of tela choroidea. Both arachnoid layers end near the foramen of Monro.ConclusionsThe membranous roof of the third ventricle comprises two layers of the tela choroidea and two arachnoid layers. These two arachnoid layers are derived from the arachnoid envelope over the pineal region.

Secondary abscess arising in a craniopharyngioma

An abscess arising in a craniopharyngioma is rare, but has potentially high mortality and morbidity. Diagnosis is difficult because clinical and neuroradiological characteristics are not clearly defined. We report a patient with a pituitary abscess concomitant with a craniopharyngioma and discuss the pathophysiological mechanism. We discuss the previous five reports and suggest that abscesses with craniopharyngioma remain challenging clinical entities. We speculate that inflammation is a response to components of the ruptured epithelium of the cyst, thereby providing an explanation of the mechanism of abscess formation.

Response to the letter “Craniopharyngioma involving the third ventricle floor”

Dear Editor: With great appreciation and acknowledgement, we carefully read the letter from Dr. Pascual et al., and are impressed by their extremely thorough and thoughtful consideration of the growth pattern of craniopharngiomas (CPs). Firstly, we unfeignedly thank them for their support of the concept of third ventricular floor CPs, which entails that the CPs, traditionally thought to be located inside the cavity of the third ventricle (intraventricular CPs), lie underneath the nervous tissue layer and pia mater; superiorly, the nervous tissue layer and ependyma are both found to be intact. However, it is indispensable and meaningful to address and exemplify the controversies proposed in this letter.

Osteoblastic differentiation and cell calcification of adamantinomatous craniopharyngioma induced by bone morphogenetic protein-2.

BACKGROUND The calcification of adamantinomatous craniopharyngioma (ACP) often creates difficulties for surgical therapy. Nevertheless, the mechanism of ACP calcification is unclear. Our previous studies demonstrated that osteoblastic factors might play important roles in ACP calcification. OBJECTIVE We examined the effects of recombinant human Bmp2 on ACP cell differentiation by testing osteoblastic proteins and calcium deposition. METHODS The expression of osteoblastic factors including osteopontin (OPN), Runx2, and osterix in Bmp2-treated ACP cells was examined by western blot and/or real time PCR. ALP activity and calcium deposition after Bmp2 induction were also tested. RESULTS Bmp2 significantly amplified the expression of Runx2, Osterix and OPN, as well as ALP activity. Both of these effects could be repressed by noggin treatment. Bmp2 also significantly induced the calcification of ACP, and noggin inhibited this calcium deposition. CONCLUSION Our study demonstrated for the first time that ACP cells could differentiate into an osteoblastic lineage via induction by Bmp2. The mechanism of ACP calcification likely involves osteoblastic differentiation modulated by Bmp2. Further studies targeting Bmp2 cascades could result in novel therapeutic interventions for recurrent ACP.