Bilateral retiform Sertoli-Leydig cell tumour in a bitch. Alpha-inhibin and epithelial membrane antigen as useful tools for differential diagnosis

Sertoli-Leydig cell tumours with a retiform pattern similar to the pattern of the rete testis are a subtype of sex cord-stromal tumours recognized in the human WHO histological classification of ovarian tumours but not in the equivalent classification for domestic animals. The morphology of the tumour may be confused with that of the more common ovarian epithelial tumours. The gross, microscopical and immunohistochemical features of a canine retiform Sertoli-Leydig cell tumour and its comparison with the human counterpart are presented in this report. Both ovaries were enlarged and cystic. Microscopically, the tumour was cystic with tubulopapillary growth characterized by narrow, elongated branching tubules. Immunohistochemically, the tumour cells expressed alpha-inhibin, while epithelial membrane antigen was not detected, indicating a sex cord-stromal origin of the tumour. Additionally, the tumour cells expressed cytokeratin and vimentin in addition to oestrogen receptor alpha and progesterone receptor.     

Keratin, luminal epithelial antigen and carcinoembryonic antigen in human urinary bladder carcinomas. An immunohistochemical study

14 urinary bladder carcinomas of all main types were investigated with antisera to "broad spectrum keratin" (aK), "luminal epithelial antigen" (aLEA) and carcinoembryonic antigen (aCEA), using an indirect immunoperoxidase method on formalin fixed paraffin embedded sections. Keratin and LEA were both present in normal transitional epithelium, papilloma and carcinoma in situ whereas CEA was absent. Transitional cell carcinomas reacted with both aK and aLEA whereas CEA was seen only in a few foci. In squamous metaplasia and squamous carcinoma reaction with aK was particularly strong, while LEA was almost lacking and CEA was present in necrotic centres. In adenocarcinomas aK and aLEA reacted equally while aCEA reacted only on the surface.     

Similarities of antisera to casein and epithelial membrane antigen

Summary Antisera raised against human milk fat globule membranes and against the casein fraction of human milk have been compared. Using an immunohistochemical stain of tissue sections it has been shown that many of the antigenic determinants detected by the different antisera are identical. A radioimmunoassay for epithelial membrane antigen (EMA) showed that casein preparations are associated with small quantities of EMA. Antisera to casein frequently contained appreciable concentrations of antibodies to EMA and this accounts for the immunohistochemical staining of non-mammary tissues.     

Immunohistochemical demonstration of epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), and keratin on mammary and extramammary Paget's disease

We examined the presence and the distribution of epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), and keratin in 4 cases (6 specimens) of mammary Paget's disease and 9 cases (18 specimens) of extramammary Paget's disease utilizing immunoperoxidase technique. Paget's cells in 23 out of 24 specimens were demonstrable for EMA. Positive staining was observed for CEA in every specimen. Among the 24 specimens, 16 showed positivity for keratin. In addition, CEA was positive in Paget's cells and the staining for CEA was stronger than that of EMA and keratin. On the other hand, some Paget's cells were negative for EMA of keratin although other positive cells were observed in the same sections. This findings indicates that Paget's cells might express CEA and/or EMA and/or keratin depending on their differentiation. EMA is present in most organs showing glandular differentiation, and anti-keratin antibody used in this study recognizes not only keratinocytes but glandular cells. Thus, our study suggests Paget's cells are of glandular origin.     

Endocervical tubal metaplasia and adenocarcinoma in situ: role of immunohistochemistry for carcinoembryonic antigen and vimentin in differential diagnosis

Eighteen cases of endocervical tubal metaplasia (tubal metaplasia) and 16 cases of adenocarcinoma in situ were reacted immunohistochemically for carcinoembryonic antigen (CEA) and vimentin. Whereas CEA was more frequently positive in adenocarcinoma in situ cases (63%) than in tubal metaplasia cases (39%), vimentin was not expressed in adenocarcinoma but was positive in 78% of cases of tubal metaplasia.     

An immunohistochemical study of distribution of carcinoembryonic antigen in epithelial tumours of the ovary.

An immunohistochemical study of the tissue CEA content of 82 epithelial neoplasms of the ovary has shown that mucinous tumours contain more of this substance than do their serous counterparts; otherwise a knowledge of tissue CEA content appears to be of little value in the differential histological diagnosis of this group of neoplasms. Among mucinous tumours there is only a partial correspondence between their degree of malignancy, as assessed histologically, and their content of CEA. It is postulated that immunohistological study of tissue CEA may add a degree of finesse to morphological analysis of these neoplasms and thus allow for a more precise grading of their degree of malignancy.     

Basement membrane and apocrine epithelial antigens in differential diagnosis between tubular carcinoma and sclerosing adenosis of the breast.

The distributions of defined basement membrane proteins in nine pure tubular carcinomas, 10 cases of sclerosing adenosis, and 15 ductal adenocarcinomas were compared. Sections of formalin fixed, paraffin embedded specimens were pretreated with pepsin and then immunostained for laminin, type IV collagen, and basement membrane proteoglycan, components specific for basement membranes. In sclerosing adenosis the tubules were surrounded by a continuous intact basement membrane composed of laminin, type IV collagen, and basement membrane proteoglycan, while the epithelium in the tubular carcinomas was negative for these proteins. The tumours were also analysed for the distribution of the apocrine epithelial antigen (AEA). In contrast to the benign lesions the tubular carcinomas expressed the AEA in a distinct non-polar fashion throughout the cell surface. In normal ducts and in adenosis the AEA was confined exclusively to the luminal surface. These studies suggest that there is a disturbance of cell polarity in tubular carcinomas. It is concluded that a combined analysis of basement membrane proteins and luminal surface antigens is a reliable and convenient way to differentiate between tubular carcinoma and sclerosing adenosis of the breast.     

Epithelial markers in prostatic, bladder, and colorectal cancer: an immunoperoxidase study of epithelial membrane antigen, carcinoembryonic antigen, and prostatic acid phosphatase

Twenty prostatic adenocarcinomas, 20 transitional cell carcinomas of the bladder, and 20 colorectal adenocarcinomas were stained for epithelial membrane antigen, carcinoembryonic antigen, and prostatic acid phosphatase. Polyclonal affinity purified first and second antibodies and an indirect immunoperoxidase technique were used. All of the colorectal and bladder tumours and 16/20 prostatic tumours were positive for epithelial membrane antigen. All 20 colorectal, 7/20 bladder, and 5/20 prostatic tumours stained for carcinoembryonic antigen. All of the prostatic adenocarcinomas and none of the colorectal or bladder tumours were positive for prostatic acid phosphatase. These markers may be used to discriminate between tumours arising from these sites.     

Immunoreactivity for cytokeratin and epithelial membrane antigen in leiomyosarcoma

Thirty-three leiomyosarcomas (LMS), which were verified by electron microscopy and by desmin and muscle actin immunoreactivity, were immunohistochemically evaluated for the presence of cytokeratin and epithelial membrane antigen (EMA) with monoclonal antibodies. None of the tumors showed any epithelial component by structure; all were homogeneous spindle cell neoplasms. Cytokeratin immunoreactivity was found in 14 of 33, and EMA in 20 of 33 LMS, usually in a large number of tumor cells. One case was confirmed as cytokeratin-positive in frozen sections with four different monoclonal antibodies. These results show that immunoreactivity for epithelial markers can be present in pure smooth-muscle sarcomas. Thus, such immunoreactivity cannot be regarded as a specific feature of carcinomas, synovial sarcoma, or epithelioid sarcoma, which are already known to be cytokeratin- and EMA-positive.     

Evaluation of PAS-diastase and carcinoembryonic antigen staining in the differential diagnosis of malignant mesothelioma and papillary serous carcinoma of the ovary

A series of malignant mesotheliomas and papillary serous carcinomas of the ovary were stained using the periodic acid Schiff reaction with diastase digestion (PAS-D) and an immunoperoxidase technique for carcinoembryonic antigen (CEA). The methods were evaluated in terms of repeatability and validity. Staining reactions were classed as positive or negative by three 'blinded' observers. Within-observer repeatability was greater for PAS-D than for CEA but there was no statistically significant difference for between-observer repeatability. The validity of the methods clearly differed, however, since the sensitivity and specificity of CEA were consistently less than that of PAS-D. Our most consistent estimates of sensitivity and specificity were compared with those of other studies and the reasons for this difference were analysed. Positive PAS-D and CEA staining were uncorrelated but a combination of the two did not appear significantly superior to PAS-D alone. We believe that PAS-D remains the method of choice for differentiating peritoneal mesotheliomas and disseminated papillary serous carcinoma of the ovary in the absence of reliable evidence of an ovarian primary because the significance of CEA positivity in occasional mesothelial tumours remains to be determined.     

The utility of epithelial membrane antigen and vimentin in the diagnosis of chromophobe renal cell carcinoma

We evaluated the immunohistochemical expression of epithelial membrane antigen (EMA) and vimentin (VMT) in chromophobe renal cell carcinoma (CHRCC). We also studied the utility of EMA and VMT immunostains in helping differentiate CHRCC from renal oncocytoma and conventional (clear cell) renal cell carcinoma with granular morphology (GCRCC). Immunohistochemical staining for EMA and VMT was performed on 21 cases of CHRCC, 16 cases of renal oncocytoma, and 28 cases of GCRCC. The diagnosis in all cases was by concurrence of all pathologists involved in the study and was based entirely on examination of routinely stained slides. All cases were classic examples of these tumor types and presented no diagnostic difficulties. The intensity of immunohistochemical staining was graded on a scale of 0 to 3 (0 = no staining; 1 = equivocal; 2 = unequivocal, moderate intensity; and 3 = unequivocal, high intensity). Positive immunohistochemical staining was defined as unequivocal staining of at least 20% of the neoplastic cells. All cases of CHRCC were positive for EMA and negative for VMT. The same immunophenotype was observed in 75% of renal oncocytoma and 21% of GCRCC. In summary, all CHRCC cases in our study demonstrated immunohistochemical staining for EMA and not VMT. However, we also found that the same immunophenotype is observed in 75% of renal oncocytoma and in 21% of GCRCC, precluding its utility for positive identification of CHRCC. Nevertheless, the lack of such an immunophenotype is a reliable indication that a neoplasm under consideration is not CHRCC.     

Plasma carcinoembryonic antigen concentrations and immunohistochemical patterns of epithelial marker antigens in patients with large bowel carcinoma.

Carcinoembryonic antigen (CEA), secretory component (SC), and epithelial IgA were traced by paired immunofluorescence staining in 102 large bowel carcinomas from 99 patients. The immunohistochemical results were evaluated semiquantitatively in relation to histological tumour grade, clinicopathological stage, and preoperative plasma CEA concentration. CEA expression was significantly increased (p less than 0.05) in the following order: histologically normal colon mucosa, transitional mucosa adjacent to tumours, neoplastic epithelium; the reverse was true for the expression of SC and epithelial IgA (p less than 0.01). CEA was significantly more abundant in the moderately and poorly differentiated tumors than in the well differentiated ones (p less than 0.05), whereas the latter showed better expression of SC (p less than 0.05) and epithelial IgA (p approximately 0.06). In the transitional mucosa, CEA staining tended to be inversely related to histological tumour grade, whereas SC and epithelial IgA were significantly better seen in this zone when the adjacent tumour was well differentiated than when it was moderately or poorly differentiated (p less than 0.01). Furthermore, the expression of SC and epithelial IgA in the transitional mucosa decreased with increasing invasiveness of the tumours, whereas the opposite relation was indicated for CEA expression. Plasma CEA concentrations were not clearly correlated with histological levels than the localised well differentiated tumours tended to be associated with lower levels than the localised moderately differentiated ones (p approximately 0.06). Moreover, the latter variety was associated with lower plasma CEA concentrations than disseminated tumours of comparable differentiation (p less than 0.01).     

Differential reactivities of carcinoembryonic antigen (CEA) and CEA-related monoclonal and polyclonal antibodies in common epithelial malignancies.

To evaluate the role of carcinoembryonic antigen (CEA) in solving problems of tumor histogenesis in surgical pathology, monoclonal antibodies to four distinct epitopes of CEA (E-Z-EM) were applied to paraffin sections of 303 epithelial neoplasms from multiple sites. Two epitopes were CEA specific (D14 and B7.1), one was shared with nonspecific cross-reacting antigen (NCA) (B7.8), and the fourth (B18) was common to CEA, NCA, and biliary glycoprotein antigen (BGP). A sample of the tumors (n = 110) was also stained with a polyclonal anti-CEA (DAKO). Gastrointestinal adenocarcinomas, including esophageal and gastric (n = 19), small intestinal (n = 8), colorectal (n = 56), biliary tract (n = 8), and pancreatic adenocarcinomas (n = 14), were consistently positive with all five antibodies. Other predominantly gland-forming carcinomas tested, comprising lung (n = 22), ovary (n = 18), and endometrium (n = 12), were either invariably negative with all five antibodies (endometrial adenocarcinoma, non-mucinous ovarian adenocarcinoma) or demonstrated selective and variable positivity (lung: D14, 50%; ovarian mucinous: D14, 50%). Among large polygonal cell carcinomas (hepatocellular carcinoma, renal cell carcinoma, melanoma, and adrenal carcinoma), only hepatomas stained positively, showing a distinctive canalicular staining pattern with the B18 (BGP epitope) (55%) and polyclonal antibody (50%). In the small polygonal cell carcinoma category, true CEA positivity was rare in breast (D14, 10% and B7.1, 14%) and never seen in prostatic carcinomas and carcinoid tumors. A subset of these breast (8 of 42), prostate (4 of 22), and carcinoids (4 of 7) showed exclusive positivity for the B18 antibody (NCA/BGP epitope). Ovarian serous papillary carcinomas (n = 14), papillary carcinomas of thyroid (n = 12), transitional cell carcinomas of the bladder (n = 11), and mesotheliomas (n = 3) were negative with all monoclonal antibodies. Metastatic carcinomas (n = 74) showed a similar pattern of reactivity to primary tumors. The authors conclude that CEA immunostaining may assist in identifying the histogenesis of epithelial tumors in several morphologic categories; that differential reactivities of the CEA monoclonal antibody panel exceed those of the polyclonal antibody; and that the discriminating power of the monoclonal panel is related to whether (1) CEA is or is not produced or (2) NCA or BGP is produced without concomitant CEA production. There is little evidence to support a concept of site-specific CEA species.