Fine structure of ossification in craniopharyngiomas

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.

Rathke Cleft Cyst with Entirely Ossified Cyst Wall and Partially Solid Cyst Content: A Case Report and Literature Review

BACKGROUND

In Rathke cleft cysts (RCCs), inflammation by the cyst contents infrequently spreads to the surrounding structures. Calcification, which is regarded as a result of chronic inflammation of the cyst wall, can rarely be found in RCCs. Moreover, ossification is extremely rare.

CASE DESCRIPTION

A 60-year-old woman experienced headaches, fatigue, and weight loss owing to pan-hypopituitarism. Magnetic resonance imaging revealed a mass lesion in the sellar region, which was composed of two different parts, with hypointensity anteriorly and hyperintensity posteriorly on T1-weighted image, and the rim with significant hypointensity entirely on T2-weighted image. During the transsphenoidal surgery, the cyst wall was so rigid that it was difficult to cut and remove it. The cyst contained mucinous fluid with both old and new hemorrhages, and a yellowish, elastic hard, solid nodule. Postoperative histologic diagnosis was RCC with unusual lymphocyte infiltration, massive granulation, and mature bone formation. Six months later, the fluid in the cyst reaccumulated, and the patient complained of headaches. Removal of the entire cyst wall and the aspiration of the cyst content were performed to collapse the cyst cavity and, consequently, to prevent further recurrence. Postoperatively, panhypopituitarism was unchanged and the symptoms were treated with hormonal replacement. The cyst has not recurred for 2 years after the second surgery.

CONCLUSIONS

Persistent, long-term inflammation induced by the RCC content, mucin-containing fluid, and several phases of hemorrhage presumably promoted the formation of mature bone on the cyst wall and of the elastically solid nodule within the cyst.

Ultrastructural characterization of craniopharyngioma at the tumor boundary: A structural comparison with an experimental toxic model using "oil machinery" fluid, with emphasis on Rosenthal fibers

Craniopharyngiomas (CPs) are cystic, encapsulated, slow-growing epithelial tumors. CPs can be aggressive forms invading and resorting surrounding structures of adjacent brain tissue, where Rosenthal fibers (RFs) are expressed. The aim of this study was to investigate the ultrastructure of these fibers in human biopsies and compare it with an experimental toxic model produced by the cortical infusion of the oil cyst fluid ("Oil machinery" fluid or OMF) from CPs to rats. For this purpose, the CPs from ten patients were examined by light and electron microscopy. OMF was administered to rats intracortically. Immunohistochemical detection of glial fibrillary acidic protein (GFAP) and vimentin was assessed. In both freshly obtained CPs and rat brain tissue, the presence of abundant cellular debris, lipid-laden macrophages, reactive gliosis, inflammation and extracellular matrix destruction were seen. Ultrastructural results suggest focal pathological disturbances and an altered microenvironment surrounding the tumor-brain junction, with an enhanced presence of RFs in human tumors. In contrast, in the rat brain different degrees of cellular disorganization with aberrant filament-filament interactions and protein aggregation were seen, although RFs were absent. Our immunohistochemical findings in CPs also revealed an enhanced expression of GFAP and vimentin in RFs at the peripheral, but not at the central (body) level. Through these findings we hypothesize that the continuous OMF release at the CPs boundary may cause tissue alterations, including damaging of the extracellular matrix, and possibly contributing to RFs formation, a condition that was not possible to reproduce in the experimental model. The presence of RFs at the CPs boundary might be considered as a major criterion for the degree of CPs invasiveness to normal tissue. The lack of RFs reactivity in the experimental model reveals that the invasive component of CPs is not present in the OMF, although the fluid per se can exert tissue damage.

Giant cranionasal and cystic-solid craniopharyngioma associated with extensive bone erosion and ossification

Craniopharyngioma (CP), a rare benign and slow-growing epithelial tumor, is mainly located within the sellar/parasellar region. Primary CP involving the nasal cavity and the sellar region with extensive erosion of the skull base and ossification simultaneity has not been described previously. The authors report a 23-year-old man who presented to our institute with complaints of repeated nasal cavity bloodshed, liquid flow, and progressive visual loss. A neuroimaging examination showed a giant cranionasal and cystic-solid CP extending from the suprasellar region to the nasopharynx with inhomogeneous enhancement, which is associated with extensive erosion of the skull base and ossification. The patient underwent a transsphenoidal surgery to resect the nasopharyngeal component of CP and a subfrontal craniotomy with a total removal of intracranial component by grinding 3 months later. A histopathologic examination revealed characteristic features of adamantinomatous CP associated with ossification. The current study demonstrates that CP can exhibit cranionasal growth pattern and arise from residue of craniopharyngeal duct. Extensive erosion of the skull base, calcification, and ossification can present in tumor simultaneity. A 2-stage stratagem is important for its total removal because of the peculiar hardness. Postsurgical course is unevenly and should be dealt with carefully.

Does the calcification of adamantinomatous craniopharyngioma resemble the calcium deposition of osteogenesis/odontogenesis?

AIMS

Calcification in adamantinomatous craniopharyngioma (ACP) is troublesome for surgical intervention. The aim of this study was to examine the osteogenic proteins that play important roles in the calcium deposition of the odontogenic/osteogenic tissues in craniopharyngioma.

METHODS AND RESULTS

Craniopharyngiomas (n = 89) were investigated for the presence and expression pattern of the osteoinductive/odontoinductive factor bone morphogenetic protein-2 (Bmp2) and two osteoblastic differentiation makers, Runt-related transcription factor-2 (Runx2) and Osterix, using immunohistochemistry and Western blotting. Our results showed that Bmp2, Runx2 and Osterix levels increased in cases with high calcification and correlated positively with the degree of calcification in ACP, whereas they showed little or no expression in squamous papillary craniopharyngioma. In ACP, Bmp2 was expressed primarily in the stellate reticulum and whorl-like array cells; Runx2 and Osterix tended to be expressed in calcification-related epithelia, including whorl-like array cells and epithelia in/around wet keratin and calcification lesions.

CONCLUSIONS

Our study indicated, for the first time, that osteogenic factor Bmp2 may play an important role in the calcification of ACP via autocrine or paracrine mechanisms. Given the presence of osteogenic markers (Runx2 and Osterix), craniopharyngioma cells could differentiate into an osteoblast-like lineage, and the process of craniopharyngioma calcification resembles that which occurs in osteogenesis/odontogenesis.

Morphological and Ultrastructural Findings of Prognostic Impact in Craniopharyngiomas

Craniopharyngioma is a slow-growing epithelial tumor with an unpredictable tendency to recur. To verify the reliability in predicting the clinical outcome, some morphological and immunohistochemical findings were analyzed in 37 primitive tumors and in 6 recurrences (one recurred twice). All the tumors were surgically excised and all recurrences exhibited an adamantinomatous pattern; mitotic rate was low (< 5 x 10 HPF) in both recurrent and in nonrecurrent tumors. Primary tumors showed a mean positivity of 1.7% (range 0.3-2%) to PCNA vs. 4.1% (range 0.3-8%) in recurrences. The MIB-1 Labelling Index was: 22.12% in primary tumors, 27.5% in recurrences, 31.3% in adult nonrecurrent tumors, and 4.1% in the pediatric tumor. CD34 labeling vessels/field was 9.3 in primary tumors and 9.91 in the recurrences; VEGF expression was higher in recurrences than in primary tumors (40 vs. 25%). Ultrastructural analysis showed fenestrated endothelium with hydropic changes in VEGF-positive vessels. Lack of clear correlations between morphological or immuno-staining patterns and behavior suggests that these features have no prognostic value in adult as well as in pediatric craniopharyngiomas. In this study, the only results that may be related to the aggressiveness of tumor is the major vascularization in the recurrent tumors in which the vessels show also ultrastructural changes.

Autopsy findings of a craniopharyngioma with a natural course over 60 years

BACKGROUND

We report the histologic manifestations in an autopsy case of craniopharyngioma with an unusually long treatment-free course.

CASE DESCRIPTION

A 72-year-old woman with craniopharyngioma, in whom ateliosis due to the suprasellar tumor had been identified at the age of 10 years but had not been treated, was studied postmortem. She had not acquired secondary sex characteristics. At autopsy, a hard mass 2 cm in diameter was present in the suprasellar region and invaded the anterior floor of the third ventricle. Histologically, a large proportion of the mass was replaced by wet keratin, ossified tissue, dystrophic calcification, and fatty adipose tissue: these features indicate widespread degeneration of the tumor cells. Only a few residual cell nests of craniopharyngioma-composed of squamous cells lined with a single columnar cell layer-were observed at the peripheral portion of the mass. Conspicuous reactive astrocytosis with relatively high cellularity was evident in the brain tissue adjacent to the mass.

CONCLUSION

This case may represent a rare example of craniopharyngioma lacking spontaneous growth activity and consequently showing marked degeneration of the tumor cells.