Langerhans'' cells and T cells in human skin tumours: an immunohistological study

In this study normal skin and a range of skin tumours, both benign and malignant, have been examined using monoclonal antibodies to identify the distribution and morphology of Langerhans' cells and T cells, the distribution of T lymphocytes and their subsets have been analysed using monoclonal anti-T cell antibodies. The results indicated that Langerhans' cells can be reliably identified in both normal and malignant skin biopsies using monoclonal antibodies. A striking finding to emerge was that in benign skin lesions Langerhans' cells were increased, whereas in malignant tumours they were not only markedly depleted or absent but also grossly stunted and deformed in outline. The majority of lymphocytes surrounding these skin tumours were shown to be T cells with helper cells outnumbering suppressor cells by a ratio from 2 to 5:1. This study shows the usefulness of immunohistological techniques using monoclonal antibodies for examining the morphology and distribution of Langerhans' cells in skin pathology. In addition they are particularly appropriate for identifying their topographical relationships with other immunologically important cells such as T cells.     

Granular cell tumours revisited. An immunohistological and ultrastructural study

Twenty-five granular cell tumours were stained with a panel of antibodies to histiocytic, muscle, neural, neural crest, epithelial and endothelial markers. Electron microscopy was also performed in six cases. Twenty-four of the cases were similar morphologically and immunocytochemically. One case with features of an endothelial origin is described. The present study strongly supports the viewpoint that granular cell tumours are a distinct entity rather than being the common appearance of a group of lesions of differing histogenesis. Origin from a neural crest-derived peripheral nerve-related cell is favoured.     

Expression of cortical and medullary thymic epithelial antigens in thymomas. An immunohistological study of 14 cases including a characterization of the lymphocytic compartment

Four monoclonal antibodies against antigens expressed differentially by the normal thymus epithelium, which define the cortical, medullary and subcapsular compartments, were used for immunohistological characterization of the epithelial cells in 14 thymomas. Furthermore, thymoma-associated lymphocytes were studied with monoclonal antibodies directed against T-lymphocyte differentiation antigens (CD1a, CD3, T-cell antigen receptor). Only four of the 14 thymomas could be classified into either medullary or cortical type thymoma based on the immunophenotype of epithelial cells. Ten cases escaped immunophenotypical classification due to co-expression of medullary and cortical antigens by the tumour cells. This aberration from the normal phenotype might indicate the failure of differentiation of such tumours. The immunophenotype of the associated lymphocytes, on the other hand, made it possible to classify the tumours as cortical (5 cases), mixed (2) and medullary (3) thymomas. Four thymomas escaped this classification scheme due to the absence of lymphocytes (2) or to a hybrid immunophenotype (2). Nevertheless, thymocytes of cortical type clearly predominated and were seen in all thymomas with associated lymphocytes. This feature may constitute a good diagnostic tool in differential diagnosis since, in 28 mediastinal or extramediastinal metastasis of tumours not derived from thymic epithelium and associated with various numbers of lymphocytes, none of them were found to contain CD1a positive lymphocytes.     

Oestrogen receptors in benign epithelial lesions and intraduct carcinomas of the breast: an immunohistological study

We examined 198 breast lesions, representing commonly encountered benign epithelial proliferative disorders, lobular carcinoma in situ and intraduct carcinoma, immunohistologically for oestrogen receptors (ER). A mixture of three ER monoclonal antibodies--H222, D75 and D547--was used on sections of routinely processed and paraffin-embedded tissue blocks. Over 65% of the benign and malignant lesions showed some evidence of ER expression and significant staining was recorded by two observers in 28-31% of fibroadenomas, 18-28% of ductal epithelial hyperplasias, 30-40% of sclerosing adenosis cases, 38-45% of papillomas, 60% of in situ lobular carcinomas and 42-45% of intraduct carcinomas. Apocrine metaplastic cells and myoepithelial cells showed absent or only weak staining. Amongst intraduct carcinomas, less than 20% of comedo carcinomas and over 50% of cribriform, papillary and solid variants showed significant ER staining.     

An immunohistological study of granulomatous prostatitis

Granulomatous prostatitis may result from tuberculosis and fungal infection and has been described following prostatic surgery. In most cases, however, the aetiology is unknown, although it may be due to a reaction to extravasated or altered prostatic secretions. We have investigated cells (macrophages, lymphocytes), serum proteins (fibrinogen, alpha 1-antitrypsin) and prostatic epithelial products (prostatic-specific antigen and prostatic acid phosphatase) in diffuse granulomatous prostatitis (3 cases), focal periacinar prostatic granulomas (9) and focal prostatic infarcts (5), using an immunohistological technique. T-lymphocytes and macrophages are present in diffuse and focal granulomatous prostatitis, but few B-lymphocytes occur. Fibrinogen-related antigen is absent from granulomas, but a small amount is present within infarcts, whereas plentiful alpha 1-antitrypsin was detected both in granulomas and infarcts. Significant reduction in prostatic-specific antigen and acid phosphatase reactivity occurs in granulomatous prostatitis. This suggests that cytokines derived from activated macrophages and T-lymphocytes may be exerting a cell regulatory effect and altering cell secretions, as well as causing destruction of the prostatic epithelium.     

Involucrin expression in adnexal skin tumours

Summary The expression of involucrin was studied in a group of skin neoplasms, mostly of adnexal origin. As happens with other types of epithelial tumours, involucrin was detected in the most differentiated areas (presenting a squamoid or ductal differentiation). No reactivity was observed in non-epithelial skin tumours. These results suggest that involucrin is a specific marker for epithelial and adnexal differentiation of skin tumours and may thus be a useful aid in histopathologic diagnosis and classification of neoplasms.     

Coexpression of cytokeratins and vimentin in common epithelial tumours of the ovary: An immunocytochemical study of eighty-three cases

Summary An immunocytochemical investigation has been performed on 83 common epithelial tumours of the ovary, to ascertain their capability of expressing vimentin in addition to cytokeratins. Our results demonstrate that vimentin coexpression is related to the tumour histotype and -to a lesser extent- to the degree of differentiation of malignant variants. Indeed, most serous tumours (80%), some endometrioid adenocarcinomas, and all the clear cell carcinomas investigated exhibited a variable number of neoplastic cells co-synthesizing the two distinct intermediate filament (IF) proteins, whereas only one of 29 mucinous tumours and none of the Brenner tumours displayed vimentin-immunoreactive cells. Moreover, in serous and endometrioid carcinomas, the expression of vimentin was related to the degree of tumour differentiation, being consistently identifiable in the better differentiated cases. The immunocytochemical findings of a parallel investigation on IF expression in the ovarian coelomic epithelium and in the müllerian-derived epithelia of the female genital tract allowed us to ascertain that ovarian epithelial tumours (with the possible exception of poorly differentiated carcinomas) maintain the pattern of IF expression typical of the normal epithelia. This investigation emphasizes the usefulness of IF typing as a tool for the more precise characterization of the origin and differentiation of human neoplasms.This study was supported by grants from the Ministero della Pubblica Istruzione (Rome, Italy)     

An immunohistological study of 66 ependymomas

Sixty-six ependymomas were examined immunohistologically to determine their distribution of glial fibrillary acidic proteins, S-100 protein and vimentin. The neoplasms were subdivided into four groups: (1) ependymomas from the cauda equina, predominantly of the myxopapillary type; (2) benign ependymomas; (3) malignant ependymomas; and (4) ependymoblastomas. Marked differences in antigen reactivity were observed between each group. The intensity of the reaction with the three antibodies was strongest in malignant ependymomas. Ependymomas from the cauda equina showed a patchy distribution of positivity for the three antigens in cells surrounding blood vessels but there was no staining of collagenous septa or the myxoid areas. In ependymoblastomas, the cells of the rosettes were negative for glial fibrillary acidic protein, but there was focal positivity for vimentin and S-100. Other areas showed tumour cells containing moderate amounts of vimentin and small amounts of S-100, and a few bands of filaments positive for glial fibrillary acidic protein. The cytogenetic and biological implications of these findings are discussed.     

Malignant transformation within benign adnexal skin tumours

AIMS: To report five malignant trichogenic tumours arising in longstanding, previously benign adnexal neoplasms through malignant transformation. Malignant trichogenic adnexal tumours are extremely rare neoplasms. METHODS AND RESULTS: The patients were between 55 years and 79 years of age. Three of the tumours were located on the arms, two on the face. Three of our patients had a history of chronic lymphocytic leukaemia, one patient had a history of colonic adenocarcinoma. The duration of the tumour nodules was reported as between 20 and 40 years before sudden changes occurred. These changes included rapid growth, pain, itching, ulceration and bleeding. Histologically, all tumours were well circumscribed and encapsulated. There was a residual benign tumour component and morphological signs such as bone formation, dystrophic calcification and sclerosis suggesting long duration of the lesions. All patients except for one, who refused further clinical investigation due to her advanced age of 79 years, had an underlying systemic malignancy. CONCLUSIONS: The growth stimulus in these benign adnexal neoplasms resulting in malignant transformation may be attributed to the acquisition of additional genetic events or to immunosuppression due to an underlying neoplastic disease. Therefore, patients with systemic diseases or malignancy should be carefully examined and followed for sudden changes in pre-existing benign cutaneous tumours.     

Immunohistochemical localization of thrombomodulin in normal human skin and skin tumours

Thrombomodulin (TM) expression has been investigated in sections of normal human skin, in cultured normal human keratinocytes, and in a variety of skin tumours. TM was present in squamous epithelial cells in the spinous layer of normal epidermis and in the outer root sheath of hair follicles, but was absent in the cells of the basal layer. It appeared to be predominantly localized to the cell membrane and the intercellular bridges in these areas. Cultured normal human keratinocytes demonstrated functionally active constitutive TM expression on their cell surface. Immunoperoxidase staining of skin tumours using anti-human TM antibodies demonstrated a typical cell membrane positivity in tumours with squamous or hair follicle differentiation. Basal cell carcinomas showed TM expression only in areas where incomplete squamoid metaplasia occurred. Sweat gland tumours and lesions of the melanogenic system failed to express TM. The localization of TM by immunostaining in various benign and malignant skin tumours typically correlated with their normal skin element of origin. The physiological significance of TM expression in the epidermis is currently undefined.     

Reproducibility of a histogenetic classification of thymic epithelial tumours

A histogenetic classification of thymic epithelial neoplasms proposed by Müller-Hermelink and co-workers has been shown by a number of recent studies to be of clinical and prognostic value. Reproducibility is an important criterion for the acceptance of any new classification for general diagnostic use. The reproducibility of this classification was tested on 51 cases of thymic epithelial neoplasia, by comparing results obtained by pathologists working from published criteria only with those results obtained by the pathologists who developed the classification. In 78% of cases there was complete concordance of results. Analysis of the 22% discordant cases showed that this discordance was due to a degree of subjectivity in determining cut-off points between categories adjacent to each other in the morphological spectrum of thymic epithelial neoplasia (medullary v. mixed, cortical v. well-differentiated thymic carcinoma). In terms of the important clinical distinction between benign (medullary and mixed) thymomas and those with more aggressive biological behaviour (cortical types and well-differentiated thymic carcinoma), the degree of reproducibility was 96%. The high degree of reproducibility of this histogenetic classification of thymic epithelial neoplasms should facilitate its acceptance and use in routine diagnostic pathology.     

Control of excisional margins by conventional histopathological techniques in the treatment of skin tumours. An alternative to Mohs' technique

For histological control of excisional margins, routinely fixed tumour specimens or, under certain conditions, specimens fixed immediately in warm formalin are processed in the histology laboratory. Strips are then cut from the undersurface, edge, and cross-section of the remainder of the specimen and processed further by routine paraffin techniques until H&E-stained sections of the entire periphery and mid-section are available. We suggest that the method is simple, easy to apply, and suitable for the assessment of excisional margins of a variety of skin tumours. Extremely low recurrence rates over a relatively long follow-up period substantiate the effectiveness of the method.     

Primary thymic epithelial tumours of the pleura mimicking malignant mesothelioma

AIMS: To illustrate the macroscopic, light microscopic and immunophenotypic similarities that exist between primary pleural thymic epithelial tumours and diffuse malignant mesothelioma. To investigate the expression of the mesothelial markers, cytokeratin (CK) 5/6, calretinin and thrombomodulin in a series of mediastinal thymic epithelial tumours. METHODS AND RESULTS: Over a 10-year period, 64 diffuse pleural tumours of non-mesothelial histogenesis were identified in the files of referrals to the South Wales regional thoracic centre (Llandough Hospital, Cardiff). Of these, five pleural tumours were diagnosed as primary pleural thymic epithelial neoplasms. From the files of the Mesopath group, Caen, three additional cases of thymic epithelial tumours with pleural involvement were identified. The study group comprised eight cases (four males, four females) with median age at presentation of 56 years (range 19-75 years). In one case there was a history of asbestos exposure. Macroscopically, seven tumours formed diffuse pleural masses. No mediastinal abnormality or intraparenchymal lesions were seen in five cases. By light microscopy, seven thymic epithelial neoplasms showed a lobulated architecture, one appeared extensively cystic. The tumours were of varied morphological subtypes: one medullary (WHO Type A), two mixed (WHO Type AB), three predominantly cortical (WHO Type B1) and two cortical (WHO Type B1). The subtypes morphologically mimicked sarcomatoid, biphasic, lymphohistiocytoid variant and epithelioid mesothelioma. The pleural thymic epithelial tumours showed immunoreactivity with broad spectrum cytokeratin AE1/AE3 (8/8; 100%), CK5/6 (8/8; 100%), and 1/8 (13%) expressed thrombomodulin. Calretinin showed variable nuclear and cytoplasmic expression in all cases, but equivocally in the thymic epithelial cell component. In 7/8 (88%) the thymic epithelial cells exhibited focal aberrant expression of CD20. Epithelial membrane antigen (EMA) showed focal expression in the perivascular and organoid areas in 6/8 (75%) cases. Carcinoembryonic antigen (CEA) and CD34 were uniformly negative. In 4/8 (50%) cases the lymphoid cell component was of immature phenotype expressing CD99, terminal deoxynucleotidyl transferase (TdT) and lymphoid precursors had a high proliferation fraction with Ki67. In the series of 20 primary mediastinal thymic epithelial tumours tested, mesothelial marker expression revealed CK5/6 (20/20), thrombomodulin (3/20; 15%) and calretinin (0/20; 0%). Varying amounts of calretinin-positive stromal cells were present. CONCLUSION: Primary pleural thymic epithelial tumours are rare but may mimic malignant mesothelioma by forming diffuse serosal-based masses. In addition, both tumours may show morphological diversity (with epithelial, spindled and mixed components present). An awareness that thymic epithelial tumours may variably express the mesothelial markers CK5/6, calretinin and thrombomodulin prevents misdiagnosis. In the distinction from malignant mesothelioma a lobulated architecture and organoid features favour a thymic epithelial neoplasm. The presence of aberrant CD20 expression in a cytokeratin-positive epithelial neoplasm and/or the presence of an immature lymphoid population (by demonstration of CD1a, CD2, CD99 and TdT) indicates a thymic epithelial neoplasm. In contrast, nuclear calretinin expression favours malignant mesothelioma.     

Epithelial markers in primary skin cancer: an immunoperoxidase study of the distribution of epithelial membrane antigen (EMA) and carcinoembryonic antigen (CEA) in 65 primary skin carcinomas

Sixty-five primary malignant skin tumours have been stained for carcinoembryonic antigen (CEA) and epithelial membrane antigen (EMA) using rabbit polyclonal affinity-purified antibodies and an indirect immunoperoxidase technique. The tumours consisted of 15 invasive squamous carcinomas, 23 basal cell carcinomas, 16 malignant eccrine poromas (porocarcinomas), and 11 sebaceous carcinomas. The basal cell carcinomas were negative for CEA and EMA except where there was keratotic or sebaceous differentiation. All the sebaceous and squamous carcinomas and 15/16 porocarcinomas contained EMA. 12/15 squamous carcinomas were positive for CEA. The malignant poromas were negative for CEA except on the ulcerated surface of two. In tumours classified as sebaceous carcinomas there was positive staining for CEA in some cells, cyst contents and/or keratotic foci. These findings have implications for the use of immunoperoxidase localization of epithelial markers in the differential diagnosis of primary and metastatic skin cancer.     

Evidence of vascular differentiation in anaplastic tumours of the thyroid - An immunohistological study

Summary Sixteen cases of anaplastic carcinoma (ACA) and 4 cases of malignant haemangioendothelioma (HAE) of the thyroid were studied by light microscopy and immunohistochemistry.Seven cases of ACA and 3 cases of HAE were characterized by coexpression of immunohistological features of epithelial and vascular endothelial cells.Expression of vimentin was common to all tumours investigated. The present study provides evidence that ACA and HAE are partially closely related tumours showing alternating differentiation. This speaks in favour of a common neoplastic cell with the potential for epithelial and vascular endothelial differentiation.F. Eckert was supported by the Dr. Mildred Scheel-Stiftung/ Deutsche Stiftung für Krebshilfe. U. Schmid was supported by the Krebsliga St. Gallen/Appenzell     

Choroid plexus papillomas: an immunohistological study of 16 cases

Eleven benign and five malignant choroid plexus papillomas in children and adults were studied immunohistologically with a panel of antibodies against glial fibrillary acidic protein, S-100 protein, vimentin, desmin, epithelial membrane antigen and two different cytokeratins (LP34 and CAM 5.2). Glial fibrillary acidic protein was focally present in epithelial tumour cells, in cells within solid areas and in clusters of cells within the stroma. S-100 protein was diffusely present in tumour cells with focal accentuation. Vimentin was present in all cases, the epithelial tumour cells demonstrating strong and diffuse positivity with perinuclear accentuation; malignant tumours, however, showed stronger positivity than benign ones. Desmin was negative in all tumours. Epithelial membrane antigen and cytokeratin (LP34) were demonstrated in four of five malignant tumours but were absent in the benign ones; CAM 5.2 reacted with four of five malignant tumours and also reacted with eight of the 11 benign ones. The significance of these findings is discussed in respect of the ontogeny of these tumours.     

Expression of parathyroid hormone related protein in normal skin and in tumours of skin and skin appendages

Parathyroid hormone related protein (PTHrP) has been demonstrated in the tumour cells of squamous cell carcinomas originating in a variety of organs, in undifferentiated small cell tumours of the bronchus, and in carcinoma of the kidney. The protein hormone is thought to produce the hypercalcaemia which may complicate some of these malignancies. By using an antibody raised in rabbits against the N-terminal portion of the molecule, the polypeptide may be demonstrated in cells of the prickle cell layer of normal skin and in the cells of hair follicles. Skin tumours showing squamous or hair follicle differentiation are shown to contain the protein antigen, while basal cell carcinomas and tumours with sweat gland differentiation do not. The hormone may be primordial in origin and the progenitor of parathyroid hormone.     

An immunohistological study of the cellular constituents of Hodgkin''s disease using a monoclonal antibody panel

Cryostat sections of lymphoid tissue from 44 cases of Hodgkin's disease were analysed by immunoperoxidase staining using a panel of monoclonal antibodies which included reagents reactive with T cells and their subsets, B cells, HLA-DR, Ig, dendritic reticulum cells and C3b receptor. A wide spectrum of immunohistological patterns was observed ranging from cases in which T cells were numerous (B cells being absent or present in only small numbers) to cases in which very prominent B cell follicles were present. These follicles contained a meshwork of dendritic reticulum cells and were composed of polyclonal B cells (as assessed by light chain expression). T cells were present in small numbers within these B cell follicles, often clustered in a thin rim around individual Reed-Sternberg and Hodgkin's cells. All B cell-rich cases were examples of lymphocyte predominant Hodgkin's disease. Assessment of the T cell helper/suppressor ratios was hindered by the fact that both anti-helper antibodies (OKT4 and anti-Leu 3a) reacted with macrophages. However the majority of cases appeared to contain a normal excess of T helper cells. HLA-DR was strongly expressed in T cell rich areas, on Reed-Sternberg and Hodgkin's cells, on vascular endothelium and on numerous infiltrating cells in the fibrous tissue areas in cases of nodular sclerosing disease. Reed-Sternberg and Hodgkin's cells were not labelled by either anti-fibronectin or by antibodies reactive with dendritic reticulum cells (anti-C3b receptor and antibody R4/23).