Growth hormone receptor expression in brain tumors

Growth hormone (GH) is essential for quality of life in both children and adults, but it is also believed to enhance the growth of various neoplasms. However, the role of GH in the brain, particularly in brain tumors, has yet to be established. To clarify these problems from the perspective of receptor expression, we examined GH receptor (GHR) expression in brain tumors using immunohistochemistry and the correlation between GHR expression and clinical features. Surgical specimens obtained from patients with brain tumors (106 pituitary adenomas, 12 craniopharyngiomas, 13 germ cell tumors, 6 medulloblastomas, and 12 malignant gliomas) were examined immunohistochemically for GHR expression. The GHR positive rate was lower in malignant tumors than in benign tumors (59% in pituitary adenomas, 73% in craniopharyngiomas, 23% in germ cell tumors, and 0% in medulloblastomas and gliomas). GHR staining in pituitary adenomas was weaker than that in normal pituitary gland. Among the GH-producing pituitary adenomas, there was no difference in size between GHR-positive and -negative tumors. However, among the non-GH-producing adenomas, GHR-positive tumors were significantly smaller. Thus, immunohistochemical GHR expression may have, at least in part, a negative impact on tumor growth potential in brain tumors.

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.

Pituitary adenoma with craniopharyngioma component

Neoplasms consisting of pituitary adenoma and craniopharyngioma components are rare and are being increasingly recognized. Their histogenesis is not clear. Most represent collision tumors; others are difficult to assess. Here, we describe a pituitary adenoma with an intermingled craniopharyngioma component, without forming 2 distinct mass lesions or histologic delineation. Areas that suggest a transition between the 2 components were also present. It was clinically a nonfunctioning adenoma, which was also negative for pituitary hormones by immunohistochemistry. Its histogenesis and implications are discussed with a review of the literature.

The Spectrum of Malignancy in Craniopharyngioma

Craniopharyngiomas are low-grade epithelial neoplasms occurring almost exclusively in the sellar/suprasellar region. Histologic malignancy is extremely rare; the literature consists mostly of isolated case reports. Herein, we report 3 patients with craniopharyngiomas exhibiting histologic malignancy, 2 of which received radiation therapy before its appearance. Hematoxylin and eosin-stained slides and selected immunohistochemical stains were reviewed in all cases. Microvessel density analysis was performed in case 2. The patients included 2 men and 1 woman, age 14, 31, and 58 years at presentation, respectively. All patients expired 3 months to 9 years after first resection and 3 to 9 months after identification of histologic malignancy. The latter developed after multiple recurrences and radiation therapy in 2 cases, but seemed to arise de novo in 1 case resembling odontogenic ghost cell carcinoma and lacking any definite low-grade craniopharyngioma precursor. The malignant component of the other 2 cases resembled squamous cell carcinoma and low-grade myoepithelial carcinoma, respectively. The MIB-1 labeling index was markedly increased in the malignant component in comparison with the low-grade precursor. Malignant transformation in craniopharyngiomas, although rare, does exist. It assumes varied histologic appearances, usually after multiple recurrences and radiation therapy, and has a near uniformly fatal outcome. De novo malignancy in odontogenic tumors of the sella is even more unusual, but also has an ominous prognosis.

beta-Catenin is expressed aberrantly in tumors expressing shadow cells. Pilomatricoma, craniopharyngioma, and calcifying odontogenic cyst

We studied the beta-catenin immunohistochemical profile in tumors expressing shadow cells: pilomatricoma, 10 cases; calcifying odontogenic cyst, 6 cases; and craniopharyngioma, 9 cases. There was strong membranous, cytoplasmic, and nuclear staining of the immature basaloid cells in all of these tumors. Shadow cells were negative in all tumors. It has been documented that rising levels of free beta-catenin drive the formation of complexes with T-cell factor/lymphoid enhancer factor (TCF-Lef) and up-regulate the wingless-Wnt cell-cell signals. The end result is an abnormality of beta-catenin degradation and, thus, a buildup of free beta-catenin in the cytoplasm and/or nucleus, resulting in the stimulation of cellular proliferation and/or inhibition of cell death. beta-Catenin seems to have an important role in the oncogenesis of these tumors. The similar pattern of keratinization in these tumors and the similar pattern of beta-catenin immunoreactivity in the cytoplasm and the nucleus are important findings. It seems that the activation of a common cellular pathway, namely Wnt-beta-catenin-TCF-Lef, has a role in the pathogenesis of these tumors. The latter could be related to their shared method of keratinization or shared dysfunction of the cellular adhesion complex leading to tumorigenesis.

Different keratin profiles in craniopharyngioma subtypes and ameloblastomas

Craniopharyngiomas are generally considered to arise from the remnants of Rathke's pouch or a misplaced enamel organ. We tried to refine these hypotheses, comparing the subtypes of craniopharyngioma with Rathke's cleft cyst, a known Rathke's pouch derivative, and with ameloblastoma, an enamel organ derivative. Nineteen craniopharyngiomas (14 adamantinomatous and 5 papillary type tumors) and 17 ameloblastomas were immunostained for cytokeratin (CK) 7, CK 8, CK 14, and human hair keratin (HHK). All cases of adamantinomatous craniopharyngioma were CK 7+/CK 8+/CK 14+. Two cases (40%) of papillary craniopharyngioma were CK 7+/CK 8+/CK 14+, whereas the remaining three cases (60%) were CK 7+/CK 8-/CK 14+. Fifteen cases (88%) of ameloblastoma were CK 7-/CK 8+/CK 14+. Only the shadow cells present in adamantinomatous craniopharyngiomas were positive for HHK, which may indicate their follicular differentiation. In Rathke's cleft cyst, ciliated cuboidal cells were CK 7+/CK 8+/CK 14- and metaplastic squamous cells were CK 7+/CK 8/CK 14+. These findings suggest that both subtypes of craniopharyngioma may differ from ameloblastoma in histogenesis, although cytokeratin expression patterns may change during tumor development. Adamantinomatous craniopharyngioma may be related to a heterotopic ectodermal tissue which can differentiate into hair follicles, while papillary craniopharyngioma may arise from Rathke's cleft cyst.

[Lipid peroxidation in the cyst fluid of craniopharyngiomas]

Comparing of the craniopharyngiomas cyst fluid, collected during the surgery, with blood plasma revealed significantly enhanced lipid peroxidation and lactate accumulation in tumour cysts contents. These processes were usually more prominent in endosuprasellar than in suprasellar craniopharyngiomas. The maximum of free radical formation in conjunction with the lowest level of malondialdehyde (MDA) was observed in primary tumours with relatively high proliferation rate. Controversial parameters ratio characterised the recurrent craniopharyngiomas, and in cyst fluids of the primary tumours with low proliferation rate the medium parameter's values were observed. Thus, the estimation of free radical formation level and MDA concentration in cyst fluid of craniopharyngioma seems to be prognostic for the tumour recurrence.

Levels of cadmium, lead, and mercury in human brain tumors

This article reports on the levels of cadmium, lead, and mercury in 21 benign brain tumors and 23 malignant brain tumors. All measurements were performed by atomic absorption spectrometry following digestion by nitric acid. Average concentrations of cadmium, lead, and mercury in brain tumors were 2.02 (ND-72.78), 0.625 (ND-83.13), and 0.118 (ND-1.96) microg/g wet weight, respectively. Our values were higher than data reported by others.

Effect of craniopharyngioma fluid on femoral vessels of rat

Craniopharyngioma fluid spillage during surgery is reported to cause aseptic meningitis, but effects of the spillage on vessels have not yet been studied. Therefore we experimentally studied the effect of external contact on femoral vessels of the rat to assess its possible role in the cerebral vascular complications. The major direct effect of the craniopharyngioma fluid on the femoral vessels was vasospasm, appearing on the fourth day after instillation. The vasospasm was observed in 83% of femoral vessels studied between 4-15 days and one of the vessels showed intra-luminal thrombus. The difference in the vessel diameter after instillation (4-15 days) was compared with the controls and was statistically significant (p < 0.01). These findings correspond well with the observed deterioration on post-operative days 5-7, due to vascular complications. No histopathologic (light-microscopic) changes of inflammation or necrosis were found in the femoral vessels. Our study shows that contact of craniopharyngioma fluid to arteries leads to vasospasm, and spillage during surgical excision may contribute to vascular complications encountered in the post-operative period. Prevention of spillage of this fluid and the routine use of cerebral vasodilators to prevent ischemic complications after craniopharyngioma surgery needs further evaluation.

Expression of vascular permeability factor in craniopharyngioma

OBJECT

The expression of vascular endothelial growth/permeability factor (VEG/PF) has recently been correlated with the presence of tumor-associated cysts in some intracranial tumors. The purpose of this study was to evaluate a possible relationship between the presence of VEG/PF and the formation of cysts in craniopharyngiomas.

METHODS

The expression of VEG/PF was studied in histological specimens from a series of 12 craniopharyngiomas. In this series, the tumors were classified as presenting a mainly solid pattern with small macroscopic cysts (four patients) or a mainly cystic pattern (eight patients). The mainly solid tumors containing small macroscopic cysts showed little or no VEG/PF positivity, which was mainly present in tumor cells surrounding cysts. Nevertheless, mainly cystic craniopharyngiomas showed a moderate or high degree of VEG/PF positivity in tumor cells.

CONCLUSIONS

These findings indicate that the predominance of a cystic or solid macroscopic appearance of craniopharyngiomas may be influenced by the degree of VEG/PF expression within the tumor cells.

CK13 in craniopharyngioma versus related odontogenic neoplasms and human enamel organ

The monoclonal antibody NCL-CK13 was studied in specimens of craniopharyngioma, ameloblastoma and calcifying odontogenic cyst neoplasms and the mandible and maxillae of normal human fetuses. There was a decrease in NCL-CK13 as the dental lamina developed, with a complete loss in the enamel organ. The neoplastic epithelia of the neoplasms revealed a clear phenotypic and immunohistochemical reactive relationship to the stratified embroyonic mucosa, away from the enamel organ. This suggests that these neoplasms might have their histogenesis from early stage epithelium, the oral part of the dental lamina or its remnants.

Intraoperative cytologic diagnosis of suprasellar and sellar cystic lesions

The intraoperative distinction of craniopharyngiomas (CP) and cystic pituitary adenomas (PA) from other intracranial parasellar cystic lesions can significantly modify the extent of surgery and reduce postoperative morbidity. Frozen-section diagnosis may be limited by the scant tissue available for examination. The imprint cytology of six parasellar cystic lesions is examined, along with their radiologic and histologic findings. These include two Rathke's cleft cysts (RCC), three CP, and one cystic PA. RCC showed scattered clusters of cuboidal cells with prominent cilia. Cystic PA demonstrated clusters of monomorphic round cells with minimal cytoplasm. CP displayed "wet" keratin and clusters of squamous cells with a palisaded border. In all six cases, cytology supported the final histologic diagnosis. In one case, the intraoperative diagnosis was based solely on cytologic examination. Cytology can contribute significantly to an accurate intraoperative diagnosis of parasellar cystic lesions and potentially modify surgical management.

Rathke cleft cyst: MR and biomedical analysis of cyst content

PURPOSE

At least one type of Rathke cleft cyst has unique MR findings, specifically, high intensity on T1-weighted images and iso- to low intensity on T2-weighted images relative to white matter. To clarify the influence of cyst content on MR images, we analyzed the cyst content by biomedical methods after surgical removal.

METHOD

We studied five patients diagnosed with Rathke cleft cyst, whose MR images showed high intensity on T1-weighted images and iso- to low intensity on T2-weighted images. After surgery, total protein and cholesterol levels were quantified, and correlations of protein and cholesterol content with T1 and T2 signal intensities were performed in vitro.

RESULTS

All five cysts had very high concentrations of protein (11,700-26,600 mg/dl, mean 17,940 mg/dl) with nearly no cholesterol (at most 2.0 mg/dl). Along with increases in protein concentration in vitro, the signal intensity of T1-weighted images increased, while that of T2-weighted images decreased. In contrast, the cholesterol concentration sequence influenced the signal intensity of neither T1- nor T2-weighted images.

CONCLUSION

The unique MR finding of Rathke cleft cysts--high signal intensity on T1-weighted images and low signal intensity on T2-weighted images--might depend mainly on protein concentration, not on cholesterol.

Human chorionic gonadotrophin immunoactivity in cystic intracranial tumours

BACKGROUND AND OBJECTIVE

With regard to intracranial tumours, elevated hCG in CSF or serum has been considered to be specific for germ-cell tumours. Recently however, elevated hCG has also been shown to be present in cyst fluid and CSF of patients with craniopharyngiomas. While germ-cell tumours are generally non-cystic, the aim of our study was to determine the significance of hCG in cystic intracranial lesions.

DESIGN

In a prospective study, hCG immunoactivity and subunits of hCG were measured in cyst fluid, CSF, and serum of patients harbouring intracranial cyst lesions.

PATIENTS AND MEASUREMENTS

hCG immunoactivity was measured in cyst fluid and serum samples of 42 patients. CSF samples were available from 12 patients with craniopharyngiomas. In order to fully characterize the hCG immunoactivity, we used immunoradiometric assays for total hCG activity (measuring both intact hCG and the free beta-subunit of hCG), and those specific for intact, dimeric hCG (hCG), free beta-subunit of hCG (hCG beta) and free alpha-subunit. Furthermore, immunostaining of tumour tissue was performed using monoclonal antibodies directed against the free beta-subunit of hCG.

RESULTS

Total hCG immunoactivity was markedly elevated in cyst fluid of all 17 craniopharyngiomas (range 36.7-4558 IU/I; normal < 5 IU/I). Moderately elevated levels of hCG in cyst fluid were detected in three of four pituitary adenomas, in two metastases from lung cancer and in two arachnoid cysts. hCG beta was detected in cyst fluid from all hCG positive cysts, while specific determination of intact (dimer) hCG and alpha-subunit mostly yielded negative results. No hCG immunoactivity was found in cystic gliomas, meningiomas or haemangioblastomas. hCG was elevated in CSF of two patients with craniopharyngiomas, but no hCG immunoactivity was detected in any serum sample. Subtle immunostaining of epithelial cell groups was shown in five of ten craniopharyngiomas. Clear immunostaining for hCG beta was also found in scattered epithelial cells of one pituitary adenoma.

CONCLUSIONS

hCG immunoactivity in cystic intracranial lesions is due mainly to hCG beta. Measurement of hCG immunoactivity in cyst fluid can be helpful in the differential diagnosis of intracranial cystic lesions, if surgery is restricted to cyst decompression and no histology is available. High levels suggest a craniopharyngioma.

[Histological analysis of craniopharyngiomas--with special reference to their histological origin and differentiation]

The histogenesis of craniopharyngiomas was immunohistochemically studied on the basis of cytokeratins (CK) expression, with special reference to histological subtype, i.e., the squamous type (Sq) and adamantinomatous type (Ad). Alcian-Blue staining and immunohistochemical expression of secretory component were also studied to assess secretory activity. Although combined expression of simple-, stratified-, and skin-type CK was detected in both Sq and Ad, the pattern of expression in Sq and Ad was different. Sq displayed epidermal differentiation of CK, and secretory activity was limited to the apical cells of Sq. Based on these findings, the histogenesis of Sq appeared to be from Rathke's pouch, but that of Ad remained obscure.

Immunohistochemical expression of human chorionic gonadotropin and P-glycoprotein in human pituitary glands and craniopharyngiomas

In order to clarify the cellular origin of craniopharyngiomas, the authors examined the distribution of P-glycoprotein (PGP) and human chorionic gonadotropin (HCG) in five normal adenohypophyses and in 23 craniopharyngiomas using peroxidase immunohistochemistry. The correlation between the expression of PGP in craniopharyngiomas and the recurrence of these tumors was also investigated. A number of pars intermedia cyst-lining cells immunostained positively for anti-PGP antibodies. A small number of adenohypophysial cells were also positive for PGP, but squamous epithelial nests were negative in all samples. However, HCG-beta was consistently demonstrated in adenohypophysial cells, pars intermedia cyst-lining cells, and squamous epithelial nests. In 11 craniopharyngiomas, the apical portion of cuboidal cells and some polygonal cells immunostained positively with anti-PGP antibodies. In four HCG-producing craniopharyngiomas, a large number of tumor cells were immunostained with anti-PGP antibodies, three of which showed a recurrence of cystic tumors. By double labeling, the coexpression of HCG-beta and PGP was demonstrated in these recurrent tumors. Accordingly, it is suggested that craniopharyngiomas produce HCG-like peptides and that craniopharyngiomas are unique squamous neoplasms arising in the sellar region from progenitor cells of a neuroendocrine lineage.

Distribution of cellular carbohydrate moieties in human dysontogenetic brain tumors, especially in craniopharyngioma and epidermoid/dermoid

Cellular carbohydrate moieties of 65 human dysonotogenetic brain tumors (craniopharyngioma, epidermoid/dermoid, Rathke cleft cyst, germinoma and non-germinomatous germ-cell tumors) and 60 common brain tumors (glioma, meningioma, neurinoma and pituitary adenoma) were investigated histochemically using sections from Ulex europaeus (UEA-1), Dolichos biflorus (DBA), peanut (PNA) and soybean (SBA), and with anti-blood group A and LewisY (LeyY) antibodies. In craniopharyngiomas and epidermoid/dermoids, it was found that PNA and SBA binding sites existed in suprabasal cells of the epithelium, and that antigen of either blood group A or H (demonstrable by UEA-1) existed in more differentiated epithelial cells compared to the results reported in normal human skin epidermis. Rathke cleft cysts were stained with PNA or SBA, and two out of three Rathke cleft cysts also expressed either H or A antigen. In addition, DBA binding sites, as well as LeY antigen, were frequently seen in craniopharyngiomas and Rathke cleft cysts, but they were entirely absent in the epithelium of epidermoid/dermoid. On the other hand, PNA and SBA reactivities was also found in common brain tumors, while blood group A, H and LeY antigens and DBA reactivity were almost absent in these tumors. These findings demonstrate that carbohydrate moieties such as those of blood group antigens reported to be found in human skin epidermis exist in a similar form in craniopharyngioma, epidermoid/dermoid and the Rathke cleft cyst. The identification of blood group A, H and LeY antigens and DBA reactivity in brain tumors seems to be considerably limited and specific.(ABSTRACT TRUNCATED AT 250 WORDS)

Suprasellar xanthomatous Rathke's cleft cyst

A case of a symptomatic suprasellar Rathke's cleft cyst in a 35-year-old woman is presented. The cyst wall and contents showed large collections of xanthomatous cells. With the exception of a few pituitary hormone-positive cells, immunohistochemical and ultrastructural features of the lining epithelium in this case of Rathke's cleft cyst were indistinguishable from colloid cysts of the third ventricle with similar secondary changes.

Cystic fluid in craniopharyngiomas: MR imaging and quantitative analysis

A prospective study of cystic fluid in craniopharyngiomas in 10 patients was performed to correlate signal intensity on T1-weighted magnetic resonance (MR) images and biochemical analysis. Within 2 days before surgery, each patient underwent MR imaging before and after administration of gadopentetate dimeglumine. Five patients had cystic fluid lower in signal intensity than white matter, with protein levels less than 9,000 mg/dL (90.00 g/L) and no free methemoglobin. One of the five patients had the highest triglyceride concentration (84 mg/dL [0.95 mmol/L]) of all 10 patients; another of these five had the highest cholesterol concentration of all (270 mg/dL [6.98 mmol/L]). It is concluded that the increased signal intensity of cystic fluid in craniopharyngiomas on T1-weighted MR images can be caused by a protein concentration greater than or equal to 9,000 mg/dL (90.00 g/L), the presence of free methemoglobin, or both. In the ranges of concentrations measured in this study, cholesterol and triglyceride did not increase signal intensity.

Secretory component of cystic craniopharyngiomas: a mucino-histochemical and electron-microscopic study

Ten cases with cystic craniopharyngioma were investigated. Histologically, eight of them belonged to the adamantinomatous group and two were squamous epithelial type. Histochemical investigation revealed mucin secretion in microcysts, and electron microscopy demonstrated zymogen granules in the epithelial cells. When the protein content of the cyst fluid was analyzed by polyacrylamide-gel electrophoresis, the electrophoretic pattern and immunological properties were found to be similar to the normal human serum control. The results of the morphological study suggest that cystic craniopharyngiomas have a secretory component in addition to the classical histological structures.

Demonstration of insulin-like growth factors I, II and heterogeneous insulin-like growth factor binding proteins in the cyst fluid of patients with craniopharyngioma

Insulin-like growth factor (IGF)-II and its binding proteins were demonstrated to be present in human craniopharyngioma cyst fluid using gel filtration and ligand blot analyses. Immunoreactive IGF-II in 3 patients was found to be 274, 232 and 310 ng/ml after gel chromatography whereas IGF-I concentrations were 13, 8 and 15 ng/ml. The IGF-II levels were severalfold higher in cyst fluid than in spinal fluid while the IGF-I levels in both fluids did not differ significantly. The binding proteins showed high affinities for [125I]IGF-II which could be displaced by unlabelled IGF-II. With the ligand blot analysis, [125I]IGF-II shows bands at 300, 175 and 46/43 kilodaltons probably representing IGF-II receptor and IGFBP-3. IGFBP-1 levels 17, 22 and 45 ng/ml, respectively, were undetectable by ligand blot.