应用组织芯片技术研究A103和inhibin α在肾上腺皮质肿瘤中的诊断价值

目的 研究肾上腺皮质肿瘤的免疫组织化学和临床病理特点及A103与inhibin α在其中的诊断价值并探讨组织芯片技术的可行性。方法 制备肾上腺皮质腺瘤(ACA)、肾上腺皮质癌(ACC)及嗜铬细胞瘤组织芯片各1个。肾上腺皮脂腺瘤芯片(79例),其中正常肾上腺皮质3例,胎儿肾上腺皮质2例,肾上腺皮质结节状增生2例,ACA72例;肾上腺皮质癌芯片(56例),其中ACC39例,肾上腺转移肿瘤17例(恶性黑色素瘤4例,转移癌13例);嗜铬细胞瘤芯片(44例)中含肾上腺髓质3例,嗜铬细胞瘤41例;20例正常成人肾上腺的常规石蜡组织作对照。用免疫组织化学EnVision法检测A103、inhibin α、calretinin、Ki-67等的表达情况。结果 A103阳性表达情况分别为正常肾上腺皮质100％(23／23),胎儿肾上腺皮质2／2,皮质增生2／2,ACA90．9％(60／66),ACC94．6％(3,5／37),肾上腺髓质及嗜铬细胞瘤阴性,转移肿瘤中除恶性黑色素瘤3／3阳性外其余均为阴性;inhibin α在正常肾上腺皮质、胎儿肾上腺皮质及皮质增生中100％表达,阳性部位主要在网状带与束状带内层,ACA阳性率75．8％(50／66),ACC75．7％(28／37),肾上腺髓质、嗜铬细胞瘤及转移肿瘤均为阴性。结论 组织芯片技术为快速原位检测提供了强有力的手段。应用组织芯片技术大规模高效检测组织样本是可行的。A103及inhibin α的联合应用对于明确肾上腺皮质肿瘤的诊断与鉴别诊断有较高价值。     

Immunoreactivity and receptor expression of insulinlike growth factor I and insulin in human adrenal tumors. An immunohistochemical study of 94 cases.

Using immunoperoxidase methods, 94 human adrenal tumors were examined for evidence of immunoreactivity and receptor expression of insulinlike growth factor I (IGF-I) and insulin. The frequency of IGF-I in adrenocortical carcinomas was significantly higher than that in adenomas of the adrenal glands. The adrenocortical carcinomas showed strong intensity of staining for IGF-I, IGF-I receptors, and insulin receptors. A significant correlation between immunoreactivity and receptor expression of both IGF-I and insulin was found only in the adrenocortical carcinomas. The adrenocortical adenomas with Cushing's syndrome and pheochromocytomas, more than adrenocortical adenomas with Conn's syndrome, also stained strongly for insulin receptors. Thus the IGF-I and insulin probably play a role in the growth of adrenocortical carcinoma tissues, possibly through autocrine mechanisms. The expression of insulin receptors in adrenocortical adenomas in the presence of Cushing's syndrome and pheochromocytomas may be associated with functions.     

Expression of argyrophilic proteins from the nucleolar organizer regions as an index of maturity degree of benign and malignant adrenal tumors

Expression of APNOR was studied in 26 benign and malignant tumors of adrenal cortex and medulla. The histochemical method with silver nitrate was used. Expression of APNOR argyrophilic proteins in adrenocortical carcinomas was 4.59 times higher than in adrenocortical adenomas and 2.63 times higher in pheochromoblastomas than in pheochromocytomas. This index may be recommended as an additional method for differential diagnosis of benign and malignant adrenal tumors, particularly in difficult border line cases as well as determination of prognosis and metastatic potential of these tumors. Cytospecificity of APNOR expression in different types of adrenal cells was established.     

Expression of HER-2/neu receptor protein in adrenal tumors

The HER-2/neu protein is overexpressed in many human carcinomas obtained from different tissues and may represent a useful target for therapy with the commercially available monoclonal antibody trastuzumab (herceptin). Novel therapeutic options are needed for metastasized adrenocortical cancer. Therefore, we studied expression of the HER-2/neu cell surface receptor protein using three different antibodies in 12 adrenal adenomas, 17 adrenocortical carcinomas and 5 pheochromocytomas. Normal adrenals (n = 5) served as controls. One adenoma showed very weak membranous immunostaining with the Dako antibody, two others showed a nonspecific cytoplasmic staining pattern. A nonspecific reaction in the cytoplasm was demonstrable in seven carcinomas with the Novocastra antibody. In all pheochromocytomas, a granular intracytoplasmic and, rarely, slightly membranous immunostaining with the Dako antibody was found. From our data we conclude that specific and significant membranous immunostaining indicating strong overexpression (grade 3) of HER-2/neu protein is not present in adrenocortical tumors. The granular cytoplasmic immunostaining of the medulla may be helpful for differentiation of adrenocortical tumors from pheochromocytomas.     

Epithelial-type and neural-type cadherin expression in malignant noncarcinomatous neoplasms with epithelioid features that involve the soft tissues

CONTEXT: Transmembrane adhesion molecules, epithelial-type cadherin (ECAD) and neural-type cadherin (NCAD), help in regulating transformations between epithelial and mesenchymal cells in the developing embryo and in maintaining the epithelioid phenotype. Consequently, the presence of epithelioid cells in certain malignant noncarcinomatous neoplasms raises speculation that the expression of ECAD and NCAD in these neoplasms may have diagnostic significance. OBJECTIVE: To investigate the utility of ECAD and NCAD immunoexpression in distinguishing malignant (noncarcinomatous) neoplasms with epithelioid features that involve the soft tissues. DESIGN: Membranous immunoreactivity of anti-ECAD and anti-NCAD was evaluated on archived cases selected from the files of the Armed Forces Institute of Pathology. RESULTS: Epithelial-type cadherin was found in biphasic synovial sarcoma (35 of 35 cases), malignant melanoma (13/21), monophasic fibrous synovial sarcoma (13/26), clear cell sarcoma (4/9), poorly differentiated synovial sarcoma (3/13), diffuse mesothelioma (4/20), malignant epithelioid peripheral nerve sheath tumor (1/6), and epithelioid sarcoma (5/62). Neural-type cadherin was observed in chordoma (11/11), biphasic synovial sarcoma (30/35), diffuse mesothelioma (14/20), malignant melanoma (14/25), epithelioid sarcoma (24/63), epithelioid angiosarcoma (1/4), poorly differentiated synovial sarcoma (2/13), clear cell sarcoma (1/10), and monophasic fibrous synovial sarcoma (1/26). Eighteen cases of primary cutaneous squamous cell carcinomas all tested positive for ECAD, whereas NCAD was focally observed in 5 cases. No expression of either molecule was observed in cases of epithelioid hemangioendothelioma (n = 9), alveolar soft part sarcoma (n = 8), and extraskeletal myxoid chondrosarcoma (n = 7). CONCLUSIONS: Epithelial-type and neural-type cadherins are found in a variety of noncarcinomatous neoplasms with epithelioid features that involve the soft tissues and can be utilized, in association with other immunomarkers, in distinguishing chordoma (100% NCAD) from extraskeletal myxoid chondrosarcoma and conventional chondrosarcoma of bone (0% NCAD), squamous cell carcinoma (100% ECAD) from epithelioid sarcoma (8% ECAD), and biphasic synovial sarcoma (100% ECAD) from diffuse mesothelioma (20% ECAD).     

Anti-CD10 (56C6) is expressed variably in adrenocortical tumors and cannot be used to discriminate clear cell renal cell carcinomas

In the evaluation of retroperitoneal masses, the practicing pathologist faces a dilemma when making a diagnosis based on histology given the often overlapping morphologic appearances of the adrenocortical carcinoma, renal cell carcinoma (RCC), and hepatocellular carcinoma (HCC). CD10 is expressed in a membranous fashion in the vast majority of clear cell RCCs; therefore, it is widely used for distinction from its mimics. However, its expression is not well-investigated in adrenal cortical tumors. We examined CD10 expression in 47 surgically resected adrenocortical tumors (26 adenomas and 21 carcinomas) and compared with 20 clear cell RCCs and 25 HCCs. Twenty HCCs (80%), 18 RCCs (90%), 11 adrenocortical carcinomas (52%), and 18 adrenocortical adenomas (69%) were positive for CD10. HCCs were characterized by a canalicular staining, and clear cell RCCs exhibited membranous or mixed membranous-cytoplasmic staining. Adrenocortical tumors displayed mainly cytoplasmic staining. Four adrenocortical carcinomas and one adenoma also displayed the membranous staining pattern. Despite the relatively small number of samples, our preliminary results revealed that adrenocortical tumors may express CD10 (Clone: 56C6). The most important point from this paper is the fact that anti-CD10 expression has not been previously reported in adrenocortical carcinomas. This suggests that CD10 does not seem to be a useful marker for discriminating clear cell RCCs from adrenocortical tumors since CD10 expression does not rule out the possibility of adrenocortical tumors. This feature should be kept in mind when constructing an antibody panel for an epithelial tumor that involves the adrenal gland and kidney, especially in small biopsy specimens.     

CD44 expression in normal adrenal tissue and adrenal tumours.

BACKGROUND: CD44 is a cell surface glycoprotein found on many normal cells, mainly lymphoid and epithelial. Normal cells usually express standard CD44 (CD44-S), whereas malignant tumours may express CD44 variant isoforms (CD44-V). CD44 expression has been described for neural crest derivatives. Characterisation of differences in CD44 expression may help in the diagnosis and differentiation of distinct adrenal tumours. AIMS: To examine CD44 expression in different layers of cortical cortex, in adrenal medulla, and in adrenal tumours. METHODS: CD44-S and CD44-V6 expression were studied in 12 cases of adrenal cortical adenoma, 3 of adrenal cortical carcinoma, 10 of pheochromocytoma, and 4 normal adrenal glands. RESULTS: CD44-V6 staining showed cytoplasmic expression in normal adrenal cortex and in cortical adenomas and carcinomas. Pheochromocytomas also showed CD44-V6 expression but in 5 of the 10 cases it was sparse, focal, and sometimes perinuclear. Strong membranous staining for CD44-S was observed in normal adrenal medulla. Analysis of CD44-S expression revealed differences between cortical adrenal tumours and pheochromocytomas. Ten of 12 cortical adenomas and 2 of 3 cortical carcinoma cells showed weak to moderate cytoplasmic staining, but all cases of pheochromocytoma had strong membranous staining. CONCLUSIONS: Membranous CD44-S staining may help to distinguish pheochromocytoma from adrenal cortical adenoma.     

DLK is a novel immunohistochemical marker for adrenal gland tumors

Delta-like protein (DLK) is expressed in fetal and adult adrenal glands. We have investigated if this expression is maintained in adrenal gland-derived tumors. All the studied 37 cortical tumors, including five carcinomas, stained positively as well as the 13 examined pheochromocytomas. Thus, DLK is a very sensitive marker for adrenal tumors of cortical and medullary origin. Renal cell carcinomas, presenting the major differential diagnostic problem for cortical tumors, were all negative, as well as melanomas, which are similar to high portion of adrenocortical tumors that react with melan-A. However, all paragangliomas, some carcinoids, and thyroid medullary carcinomas were also positive for DLK. Therefore, this novel immunohistochemical marker seems useful for the identification of adrenocortical tumors while it has limited value for the distinction of pheochromocytomas from diagnostically related neuroendocrine tumors.     

High diagnostic accuracy of adrenal core biopsy: results of the German and Austrian adrenal network multicenter trial in 220 consecutive patients

Incidentally detected adrenal tumors are a common finding during abdominal ultrasonography, computed tomography, and magnetic resonance imaging. Although most of these lesions are benign adenomas, adrenocortical carcinomas and metastases constitute 5% to 10% of all tumors. Adrenal biopsy may be helpful, but its diagnostic value is controversial and disputed, and prospective studies have not yet been performed. Therefore, the diagnostic accuracy of adrenal core biopsy was evaluated in a prospective multicenter study involving 8 surgical centers in Germany and Austria. A total of 220 biopsies from surgical specimens of the adrenal gland were punctured in an ex vivo approach and processed for pathohistologic diagnosis using paraffin sections, routine staining, and immunohistochemistry (keratin KL1, vimentin, S100 protein, chromogranin A, synaptophysin, neuron-specific enolase, D11, MiB-1, and p53 protein). The evaluating pathologist was blinded for clinical data from the patients. A total of 89 adrenal adenomas (40.5%), 22 adrenal carcinomas (10.0%), 55 pheochromocytomas (25.0%), 15 metastases (6.8%), 16 adrenal hyperplasias (7.2%), and 23 other tumors (10.5%) were studied. Nine cases were excluded due to incomplete data (n = 2) or insufficient biopsy specimen (n = 7). In the remaining 211 tumors, compared with the final diagnoses of the surgical specimen, bioptic diagnoses were absolutely correct in 76.8% of the cases, nearly correct in 13.2% of the cases, and incorrect in 10% of the cases. Pheochromocytomas were correctly diagnosed in 96% of the cases, cortical adenomas were correctly or nearly correctly reported in 91% of the cases, cortical carcinomas were correctly or nearly correctly reported in 76% of the cases, and metastases were correctly or nearly correctly reported in 77% of the cases. Of the 39 malignant lesions, only 4 were misclassified, 2 as benign and 2 as possibly malignant. This resulted in an overall sensitivity for malignancy of 94.6% and specificity of 95.3%. Our findings suggest that adrenal core biopsy is a useful method for identifying and classifying adrenal tumorous lesions if sufficient biopsy specimens can be obtained. However, in clinical practice it remains to be shown whether the benefits of biopsy outweigh the risks of the procedure.     

Prediction of malignant behavior of pheochromocytomas and paragangliomas using immunohistochemical techniques

Pheochromocytomas and paragangliomas arise from the adrenal glands and extraadrenal paraganglia, respectively. Malignant behavior of these tumors is uncommon and is, in part, dependent on their sites of origin, such as extraadrenal location. Morphologic criteria for malignancy of pheochromocytoma and paragangliomas have not been clearly defined. In this study, to clarify the histologic features that distinguish the benign from malignant pheochromocytomas and paragangliomas, we examined metastatic and nonmetastatic tumors using immunohistochemical techniques. A total of eight cases, five pheochromocytomas from the adrenal glands (four benign and one malignant tumor) and three paragangliomas with invasion or metastasis, were studied. The markers used in this study were chromogranin A, synaptophysin, NCAM (CD56), SNAP25, neuron-specific enolase, S-100 protein, and MIB-1. Our results suggest that MIB-1 immunostaining is a useful adjunct marker to predict malignant behavior in these tumors.     

Stathmin Expression in Pheochromocytomas,Paragangliomas, and in other Endocrine Tumors

Pheochromocytomas are neuroendocrine tumors confined to the adrenal glands, and malignant pheochromocytomas can spread to various sites including the liver, lung, and bones. Paragangliomas occur in numerous locations in the body, so assessment of metastatic disease is more challenging, as patients with familial syndromes often have multiple, possibly independent paragangliomas. The most reliable criterion for malignancy in pheochromocytomas and paragangliomas is metastatic disease. Because there are few immunohistochemical markers that are useful in the diagnosis of malignancy in pheochromocytomas and paragangliomas before they metastasize, more markers are needed to characterize these tumors. Stathmin is a widely expressed 17-kDa cytoplasmic, microtubule destabilizing and sequestering phosphoprotein that is important in cell motility and cancer cell metastasis. It is upregulated in various malignancies. We examined stathmin expression in tissues from patients with pheochromocytomas (n = 48), malignant pheochromocytomas (n = 28), paragangliomas (n = 42), and malignant paragangliomas (n = 21) by immunohistochemistry using tissue microarrays (TMA) with a polyclonal antibody against stathmin. A series of other endocrine tissues and tumors (n = 70) were also examined for stathmin expression. Stathmin was more highly expressed in pheochromocytomas compared to normal adrenals, a finding confirmed by Western blot. There was higher expression of stathmin by immunohistochemical staining in malignant pheochromocytomas compared to pheochromocytomas without metastasis when analyzed by maximal staining (p = 0.012). Stathmin was present in a wide variety of endocrine tumors and was most highly expressed in rapidly proliferating tumors including anaplastic thyroid carcinomas, Merkel cell carcinomas of the skin and small cell carcinomas of the lung. These results show that stathmin is expressed at higher levels in more rapidly proliferating endocrine tumors. However, it is probably not useful as a stand-alone marker to determine malignancy in pheochromocytomas for individual tumors.     

Adrenocortical carcinoma is characterized by a high frequency of chromosomal gains and high-level amplifications

Distinction of adrenocortical carcinoma from benign adrenocortical lesions by standard criteria is often difficult. In order to search for additional diagnostic parameters, a series of 25 adrenocortical tumors, 8 adenomas, 14 primary carcinomas, 1 metastasis, and the 2 adrenocortical carcinoma cell lines SW13 and NCI-H295 were analyzed by the approach of comparative genomic hybridization (CGH). Except for the two smallest adenomas, all tumors showed chromosomal imbalances with a high incidence of chromosomal gains, most frequently involving chromosomes or chromosome arms 5, 7, 8, 9q, 11q, 12q, 14q, 16, 17q, 19, 20, and 22q. The only significant loss of material concerned the distal part of 9p. Furthermore, 21 high-level amplifications were identified in 15 different regions of the genome. The consensus regions of recurrent gains and the focal high-level amplifications allowed identification of a series of chromosomal subregions containing candidate proto-oncogenes of potential pathogenic function in adrenocortical tumors: 1p34.3-pter, 1q22-q25, 3p24-pter, 3q29, 7p11.2-p14, 9q34, 11q12-11q13, 12q13, 12q24.3, 13q34, 14q11.2-q12, 14q32, 16p, 17q24-q25, 19p13.3, 19q13.4, and 22q11.2-q12. A subset of the CGH data was independently confirmed by interphase cytogenetics. Interestingly, the adenomas larger than 4 cm contained gained material of regions also overrepresented in carcinomas. In addition, several chromosomal gains, in particular the high-level amplifications, were exclusive for the malignant status of the tumors. These data indicate that the larger adrenal lesions need to be carefully considered in the diagnosis of adrenocortical tumors, and that genetic aberrations might provide useful markers for a better diagnostic differentiation.     

Pathologic features and expression of insulin-like growth factor-2 in adrenocortical neoplasms

We analyzed a series of adrenocortical neoplasms to compare the clinicopathologic features and the expression of insulin-like growth factor-2 (IGF-2) in adrenocortical adenomas and carcinomas. IGF-2 is a growth factor commonly expressed in many tumors including adrenal cortical and medullary neoplasms. Formalin-fixed paraffin-embedded tissues from 64 adrenocortical adenomas and 67 adrenocortical carcinomas were analyzed. The carcinomas were histologically graded from 1 to 4 based on mitotic activity and necrosis. Tumor weight, size, and follow-up information were obtained by chart review. Expression of IGF-2 was detected by immunohistochemistry with the avidin-biotin-peroxidase complex method and a monoclonal antibody against IGF-2. Adrenocortical carcinomas were larger (mean: 13.1 cm, 787 g) than adenomas (mean: 4.2 cm, 52 g) (p<0.001). In patients with adrenocortical carcinomas, high tumor grade (3 or 4) (p=0.01) was associated with decreased survival. Expression of IGF-2 was higher in adrenocortical carcinomas than in adenomas (p<0.001). These results show that tumor size and weight along with expression of IGF-2 protein are useful features to assist in distinguishing between adrenocortical adenomas and carcinomas, and that high tumor grade is a predictor of survival in adrenocortical carcinomas. However, single immunohistochemical markers such as IGF-2 or single histopathologic features cannot by themselves separate adrenocortical adenomas from carcinomas, and a combination of clinical, gross, and microscopic features are needed to establish the diagnosis in difficult cases.     

Decreased CD44 standard form expression correlates with prognostic variables in ovarian carcinomas.

Expression of CD44 standard form (CD44s) was evaluated by automated immunohistochemical analysis using the anti-CD44 A3D8 clone in 101 ovarian epithelial neoplasms including 82 primary tumors (64 carcinomas and 18 tumors of low malignant potential [LMP]), 9 lymph node metastases, 8 malignant ascites, and 2 peritoneal implants. Immunostaining was scored semiquantitatively. Tumors were graded according to the FIGO (International Federation of Gynecology and Obstetrics) classification system. Tumor stage and patient survival were determined from the patient records. While 9 of 18 LMP tumors expressed CD44s, only 15 of 64 carcinomas expressed it. In the carcinomas, univariate analysis revealed that decreased CD44s expression correlated with high tumor grade, advanced stage, and shortened survival. Loss of CD44s expression also was noted in the tumor cells in 8 of 9 lymph node metastases, 7 of 8 malignant ascites, and 1 of 2 implants. Multivariate analysis revealed that only tumor stage independently correlated with patient survival. Loss of CD44s expression determined by immunohistochemical analysis is more common in ovarian carcinomas than in LMP tumors; correlates with prognostic variables including tumor grade, stage, and survival; and may have an important role in the dissemination of ovarian cancer.     

Immunocytochemical differential diagnosis of adrenocortical neoplasms using the monoclonal antibody D11

Summary The monoclonal antibody D11 is a valuable aid in the accurate typing of adrenal tumours as, in formalin-fixed, paraffin-embedding material, strong nuclear D11 positivity was observed only in adrenocortical cells in 190 neoplasms (including 100 adrenal tumours). This pattern was demonstrated for all zona glomerulosa cells in 27 normal adrenals and for the neoplastic cells of 15 adrenocortical adenomas derived from that zone, as judged from clinically evident hyperaldosteronism. Normal cells of zona fasciculata and reticularis also showed strong diffuse D11 immunostaining and the same nuclear plus cytoplasmic D11 reactivity was evident in 15 benign and malignant adrenocortical neoplasms derived from these zones, documented by hypercortisolism. Cytoplasmic and/or nuclear D11 staining made topohistogenetic typing possible in 15 non-functioning cortical tumours. D11 immunostaining gave negative results in 50 specimens containing normal, hyperplastic and neoplastic adrenomedullary cells. In addition, absence of D11 reactivity was recorded in 4 adrenal metastases of extra-adrenal carcinomas, 5 paragangliomas, 25 primary renal carcinomas and 59 of 60 primary thyroid carcinomas. D11 immunocytochemistry allows the accurate typing of benign and malignant adrenocortical neoplasms, irrespective of histology and function. With this method, primary adrenocortical tumours can be separated from carcinomas metastatic to the adrenal gland, including secondary tumours of similar phenotype (such as renal carcinomas). By exclusion, D11 negativity provides evidence of the medullary origin of primary adrenal tumours even in the absence of clinical, structural, histochemical and conventional immunohistochemical indicators of phaeochromocytoma. Dedicated to Prof. Dr. Dr. h.c. mult. Wilhelm Doerr on the occasion of his 75th birthday. This study has been sponsored by the Deutsche Forschungsgemeinschaft and the Hamburger Krebsgesellschaft and was presented in part at the 80th Annual Meeting of the American Association for Cancer Research, San Francisco, California, 24–27 May 1989 (Schr?der et al. 1989)     

Differential expression of human telomerase catalytic subunit mRNA by In situ hybridization in pheochromocytomas

In pheochromocytomas, it is very difficult to predict malignant potential by conventional histology or immunohistochemical and molecular markers. We investigated the expression of human telomerase catalytic component (hTERT) mRNA, hTERT protein, Ki-67 antigen, and p27^kip1 in pheochromocytomas (27 benign, 7 suspected malignant, and 7 malignant), and evaluated the possibility of expressions of these proteins, and hTERT mRNA serve as diagnostic markers for predicting the biological behavior of these tumors. All tumors showed the classical histology and typical immunohistochemical pattern. By in situ hybridization, hTERT mRNA was expressed in 5/7 malignant tumors (defined as the presence of metastasis and/or extensive local invasion) as compared with 3/27 benign tumors. We examined the hTERT by immunohistochemistry to confirm the mRNA. hTERT mRNA expression was correlated with hTERT protein expression. All benign tumors exhibited no immunopositivity or <1% of cells stained for Ki-67 antigen. Six out of seven malignant tumors have shown either hTERT mRNA expression or Ki-67 immunoreactivity While no statistical difference in p27^kip1 expressions was observed among benign, malignant, and suspected malignant tumors, there was a statistical difference between the normal adrenal medulla samples and tumors (p<0.001). Thus, hTERT mRNA detection by in situ hybridization, hTERT expression, and Ki-67 antigen expression are all useful tools for differentiating malignant from benign pheochromocytomas.     

Expression of intermediate filament proteins in adrenal cortex and related tumours

The intermediate filament profile of adrenal cortex and its related tumours has been evaluated. Most adrenocortical cells contained cytokeratin 8 and 18 as demonstrated by monoclonal antibodies CAM 5.2, M20, M9 and RGE53. Cytokeratin immunoreactivity was not confined to a functional zone of the adrenal cortex. Only a small number of the adrenocortical cells showed vimentin immunoreactivity. From normal adrenal cortex through adenomas, to carcinomas, there is a progressive decrease or even loss of cytokeratin immunoreactivity and an increase in vimentin immunoreactivity. Aberrant cytokeratin expression was not found in adrenocortical adenomas and carcinomas with the antibodies used. Awareness of the possible absence of cytokeratin immunoreactivity in adrenocortical carcinomas is important whenever antibodies to cytokeratins and vimentin are used for diagnostic purposes in poorly differentiated neoplasms.     

VEGF in 105 pheochromocytomas: enhanced expression correlates with malignant outcome

Pheochromocytomas are rare sympathoadrenal tumors that are highly vascular. Their malignancy is extremely difficult to estimate on the basis of histopathological features. Vascular endothelial growth factor (VEGF) is one of the most important angiogenic factors involved in both tumor growth and metastasis. In our search for new prognostic markers, we investigated the expression of VEGF in normal adrenal gland, in 105 primary pheochromocytomas, and in 6 metastases by using immunohistochemistry and Northern blot analysis. We also calculated the microvessel density of these tumors by staining the endothelial cells with monoclonal CD34 antibody. VEGF messenger ribonucleic acid was found in all pheochromocytomas studied. Immunohistochemically, VEGF was not found in normal adrenal medullary cells. Interestingly, all malignant pheochromocytomas (n=8), regardless of their primary location, had strong or moderate VEGF immunoreactivity, while most benign adrenal pheochromocytomas (26 of 37, 70.3%) were either negative or only weakly positive. The staining was heterogenous in extraadrenal pheochromocytomas as well as in a group of tumors that had histologically suspicious features but had not metastasized, here called borderline tumors (n=29). The microvessel density varied greatly in all of the tumor groups, and no statistical difference was found between these groups. Here we report moderate to strong VEGF expression in malignant pheochromocytomas, and negative or weak expression in benign adrenal pheochromocytomas. Normal medullary cells are immunohistochemically negative. Thus, low VEGF expression in pheochromocytomas favors a benign diagnosis.