Epithelial Membrane Antigen Antibodies Research Articles

Upper end of the central canal of the human spinal cord: Quantitative anatomical study and 3D modeling.

The upper end of the central canal of the human spinal cord has been repeatedly implicated in the pathogenesis of various diseases, yet its precise normal position in the medulla oblongata and upper cervical spinal cord remains unclear. The purpose of this study is to describe the anatomy of the upper end of the central canal with quantitative measurements and a three-dimensional (3D) model. Seven formalin-embalmed human brainstems were included, and the central canal was identified in serial axial histological sections using epithelial membrane antigen antibody staining. Measurements included the distances between the central canal (CC) and the anterior medullary fissure (AMF) and the posterior medullary sulcus (PMS). The surface and perimeter of the CC and the spinal cord were calculated, and its anterior-posterior and maximum lateral lengths were measured for 3D modeling. The upper end of the CC was identified in six specimens, extending from the apertura canalis centralis (ACC) to its final position in the cervical cord. Positioned on the midline, it reaches its final location approximately 15 mm below the obex. No specimen showed canal dilatation, focal stenosis, or evidence of syringomyelia. At 21 mm under the ACC in the cervical cord, the median distance from the CC to the AMF was 3.14 (2.54-3.15) mm and from the CC to the PMS was 5.19 (4.52-5.43) mm, with a progressive shift from the posterior limit to the anterior third of the cervical spinal cord. The median area of the CC was consistently less than 0.1 mm2. The upper end of the CC originates at the ACC, in the posterior part of the MO, and reaches its normal position in the anterior third of the cervical spinal cord less than 2 cm below the obex. Establishing the normal position of the upper end of this canal is crucial for understanding its possible involvement in cranio-cervical junction pathologies.

Immunoexpression of epithelial membrane antigen in canine meningioma: Novel results for perspective considerations.

Epithelial membrane antigen (EMA) is one of the most widely used diagnostic immunohistochemical markers for human meningioma. To date, no published study on EMA expression in formalin-fixed paraffin-embedded (FFPE) tissue samples of canine meningioma is available. Here, we describe the results of an immunohistochemical study on 25 FFPE canine meningiomas using a monoclonal anti-human EMA antibody. All meningiomas showed positive staining for EMA with cytoplasmic pattern, in nine cases associated with membranous staining. Area and intensity of staining were highly variable among cases. No clear relationships between tumour subtype/grade and area/intensity of staining were found. However, epithelial-like patterns showed a higher affinity for EMA compared to the mesenchymal one. The present study provides the basis to explore the potential diagnostic application of this marker in canine meningioma. To investigate EMA expression in other central nervous system tumours of dogs are necessary to assess the specificity of this marker.

Detection of Micrometasteses In Lymph Nodes in Cases of Carcinoma Breast by Immunohistochemistry

Background – We evaluated archived lymph nodes of breast carcinoma for micrometastases detection by serial multiple sections (SMS) and immunohistochemistry (IHC) and found increased positive lymph nodes yield which led to change in staging in few cases, treatment and prognosis.
 Method – Metastatic free, early breast cancer cases of 36 patients with lymph node status pN0 or pN1 were evaluated. These were the cases had been treated with modified radicle mastectomy and axillary lymph node dissection. All the lymph node was cut at 50µm interval to get 5µm thick serial sections. These serial sections (SMS) were stained with Hematoxyline and Eosin (H&E). Out of these 2 sections were subjected to Immunohistochemistry (IHC). Monoclonal antibodies chosen for IHC were panCK (Cytokeratin) and EMA (Epithelial membrane antigen) to detect micrometasteses.
 Results – Total 463 lymph nodes from 36 cases of carcinoma breast were studied. New serial sections (SMS) cut from 435 lymph nodes of breast revealed 16(3.67%) additional positive lymph nodes from 12 cases. Out of 16 positive lymph nodes 4 were macrometasteses and 12 were micrometastases. Immunostaining with CK antibody revealed micrometasteses in 40 of 435 (9.19%) lymph nodes and by EMA antibody 33 of 435 (7.59%). Out of 40 micrometasteses 8 were positive for isolated tumor cells (ITC). We calculated the Z value and corresponding p value between the two methods as H&E versus SMS, H&E versus IHC and SMS versus IHC for carcinoma breasts. The tests revealed that SMS and IHC are definitely the superior methods in detection of a greater number of positive lymph nodes in cases of carcinoma breast.
 P value for detection of micrometasteses H&E versus SMS is <0.05 (S), H&E versus IHC <0.01(S) and SMS versus IHC (<0.02). Out of 36 cases 06 cases showed change in staging and 03 out of 06 cases were upstaged from early to advanced stage carcinoma.
 Conclusion – Significant number of metasteses are missed by routine processing of lymph nodes on H&E staining. SMS and IHC increase the yield of metasteses in lymph nodes. CK is superior marker than EMA.

Bladder perforation during transurethral resection of bladder tumour is not a result of a deficient structure of the bladder wall

BackgroundTransurethral resection of the bladder tumour (TUR) is associated with a risk of bladder perforation. The underlying mechanisms and risk factors are not fully understood. The aim of this study was to determine if the bladder wall structure affects the risk of bladder perforation during TUR.MethodsFifteen patients who underwent TUR complicated by a bladder perforation (group 1) and fifteen matched controls who underwent uncomplicated TUR (group 2) were retrospectively enrolled in this morphological analysis. Surgical specimens were collected from all participating patients to describe the quality and architecture of urothelium and bladder submucosa. Immunohistochemical studies were performed with primary mouse anti-human E-cadherin, beta-catenin, type IV collagen, cytokeratin 20 and epithelial membrane antigen antibodies. The intensity of the immunohistochemical reaction was assessed using an immunoreactive score (IRS). Ultrastructural examinations were performed by transmission electron microscopy. The microscopic assessment was focused on the intensity of fibrosis in the bladder submucosa and the presence of degenerative changes in the urothelium.ResultsPatients’ age, sex distribution, tumour diameters, surgeon experience or cancer stage did not differ between study groups. The immunohistochemical analysis did not reveal statistically significant differences between group 1 and group 2. From a clinical point of view, ultrastructural analysis by electron microscopy showed a higher rate of severe fibrosis in group 1 (63.6% vs. 38.5%), with no differences in the rate and degree of urothelial changes. However, these differences were not statistically significant (p = 0.32).ConclusionsBladder perforation during TUR is not a result of a deficient structure of the bladder wall. Based on available evidence, the surgical technique seems to play the most important role in its prevention.

Angiogenesis in Breast Cancer and its Correlation with Estrogen, Progesterone Receptors and other Prognostic Factors.

The aim of study is to evaluate angiogenesis using CD34, in estrogen, progesterone positive and negative breastcancer and to correlate the microvessel density with known histological prognostic factors, morphological type of breast carcinoma and lymph node metastasis. Twenty eight untreated cases of breast cancer were included in the study and paraffin embedded sections were obtained from representative mastectomy specimen of breast cancer patient. The sections were stained with hematoxylin and eosin stain and immunohistochemistry was performed using CD34, estrogen, progesterone, cytokeratin and epithelial membrane antigen antibody. Angiogenesis was analysed using CD 34 antibody. For statistical analysis, cases were grouped into estrogen, progesterone positive and negative receptors. Mean microvessel density in ER-/PR-, ER-/ PR+, ER+/PR-, ER+/PR+ was 15.45, 14.83, 11, 10.89 respectively. A significant correlation was found between ER receptors and mean vascular density with p-value (< 0.05). A significant difference was observed in mean vascular density between the four groups comprising (p-value < 0.05). Infiltrating duct carcinoma (NOS) grade III has got the highest mean microvessel density (14.17) followed by grade II (12.93) and grade I (12.33). Information about prognostic factors in breast cancer patients may lead to better ways to identify those patients at high risk who might benefit from adjuvant therapies.

Spindle cell oncocytoma of the adenohypophysis

Spindle cell oncocytoma of the adenohypophysis (SCO) is defined as spindle to epithelioid cells with oncocytic appearance presenting in the adenohypophysis. In contrast to pituitary adenomas, the SCO does not show immunoreactivity for neuroendocrine markers and pituitary hormones but co-expressed vimentin, S-100 protein, epithelial membrane antigen (EMA), and antimitochondrial antibody MU213-UC clone 131-1. We describe an SCO in an adult, a 42-year-old woman whose magnetic resonance (MR) images documented an intrasellar lesion located in the hypophysis. Histopathological examination showed a tumor composed predominantly of spindle cells. Immunohistochemical studies showed positivity for vimentin, S10, EMA, and antimitochondrial antibody MU213-UC clone 131. Cytokeratin (CK) (AE1/AE3), glial fibrillary acidic protein (GFAP), chromogranin, synaptophysin, PGP9.5, CD57, desmin, D2-40, smooth muscle actin (SMA), Bcl-2, progesterone receptor, and CD34 were negative. Neuropeptides were negative. With electron microscopy, the neoplastic cells appear filled with mitochondria, well-formed desmosomes, but lacked secretory granules. SPO is a rare non-endocrine neoplasm of the adenohypophysis with benign biological behavior corresponding to WHO grade I.

KL-6 is another useful marker in assessing a micropapillary pattern in carcinomas of the breast and urinary bladder, but not the colon

To evaluate the peculiar "inside-out" pattern in micropapillary (MP) carcinoma, we investigated the usefulness of KL-6 antibody in the assessment of the MP pattern of cancers, in comparison with antibodies to epithelial membrane antigen (EMA), MUC1 (CD227), and CD 10. Immunohistochemical investigation was performed on specimens exhibiting an MP pattern obtained from 12 persons with cancer: 4 with breast carcinoma, 3 with carcinoma of the urinary bladder, and 5 with colonic carcinoma. Immunohistochemical study with KL-6, EMA, and MUC1 antibodies revealed similar continuous linear positive patterns restricted to the surface of the MP pattern in both breast and urinary bladder cancers, revealing the peculiar "inside-out" morphology. However, EMA also gave cytoplasmic positivity in most of the cases tested, and MUC1 was also present in the cytoplasm of some cases. In sharp contrast, immune reactions of colon carcinomas with these antibodies were negative, except for focal positivity for KL-6 and MUC1 antibodies in some cases. CD10 was only focally positive in an MP pattern in 4 of the 5 cases of colon carcinoma and in 1 case with carcinoma of the urinary bladder. These findings suggest that KL-6 is a useful marker to assess the MP character of breast and urinary bladder carcinomas; that MUC1 was similarly positive, with the addition of cytoplasmic positivity in some cases; and that the MP pattern of colon cancer, positive for CD 10, was different in character from both breast and urinary bladder carcinomas, although all these cancers seemingly exhibit similar MP patterns on histopathology. This heterogeneity of the MP pattern in various cancers needs to be investigated when more cases have been accumulated.

Immunohistochemical and immunoelectron microscopic studies of the localization of KL-6 and epithelial membrane antigen (EMA) in presumably normal pulmonary tissue and in interstitial pneumonia

To clarify the localization of KL-6 and epithelial membrane antigen (EMA) in human lungs, immune reactions to antibodies to these factors were examined in detail at light and electron microscopic levels. Immunohistochemical investigation was performed in 17 cases of usual interstitial pneumonia (UIP), nonspecific interstitial pneumonia (NSIP), hypersensitivity pneumonitis (HP), collagen vascular disease-associated interstitial pneumonias (CVD-IP), viral pneumonia, and bronchobronchioloectasis, as well as in 10 cases of presumably normal pulmonary tissue resected as a result of spontaneous pneumothorax. Immunohistochemical study revealed similar discontinuous linear or dome-shaped positive patterns restricted to type II alveolar cells in presumably normal tissue and only some regions of interstitial pneumonia. In sharp contrast, immune reactions with each of the two antibodies yielded a continuous linear pattern surrounding damaged areas in most regions of interstitial pneumonias and some normal areas as well. Staining for EMA antibody was negative in some regenerating alveolar and bronchial cells in regenerating foci in interstitial pneumonias, although staining for KL-6 antibody was always positive in these cells. Immunoelectron microscopic studies demonstrated similar positive reactions with both antibodies on the surface of alveolar epithelial cells in three of the cases examined, with surface positive granules 100-200 nm in diameter. Thus, although staining for both KL-6 and EMA antibodies exhibited discontinuous positivity restricted to type II alveolar cells in nondamaged regions, immune reactions were continuous and linear in pattern in or around damaged areas of the lungs at both light and electron microscopic levels, probably as a consequence of cell-surface barrier function. These findings in pulmonary tissue might be evidence of defense functions.

Anaplastic meningioma versus meningeal hemangiopericytoma: Immunohistochemical and genetic markers

Anaplastic meningiomas (MIIIs) and meningeal hemangiopericytomas (HPCs) display significant morphologic and immunohistochemical overlap, including occasional cases of otherwise classic HPC with focal epithelial membrane antigen (EMA) positivity. The availability of several new biomarkers prompted us to examine the potential diagnostic roles of ancillary immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) studies. From the archival university neuropathology and consult files of 1 of the authors (A.P.), 19 meningeal HPCs and 19 MIIIs were retrieved for further study. IHC was performed by using EMA, CAM 5.2, CD99, Bcl-2, claudin-1 and Factor XIIIa (FXIIIa) antibodies. FISH was performed with NF2, 4.1B (DAL-1), chromosome 1p32, and 14q32 probes. HPCs showed strong CD99 (85% of cases), strong bcl-2 (86%), focal EMA (33%), focal claudin-1 (13%), and scattered individual cell FXIIIa (100%) positivity. MIIIs showed strong EMA (89%), strong claudin-1 (54%), weak or focal CD99 (15%), weak or focal bcl-2 (31%), and individual cell FXIIIa (84%) positivity. Focal CAM 5.2 expression was seen in 26% of HPCs and 15% of MIIIs. Deletions were extremely common in MIIIs: 1p (94%), 14q (67%), NF2 (100%), and 4.1B (67%). HPCs showed no 14q or 4.1B deletions, with 1 case each of 1p and NF2 deletions (6%). The sensitivities and specificities of the 3 most useful IHC markers (EMA, CD99, bcl-2) were 85%-89% and 67%-84%, respectively. The sensitivity and specificity of claudin-1 for MIII were 54% and 86%, respectively. The specificity and positive predictive value of combined CD99 and bcl-2 expression for the diagnosis of HPC was 95%. The sensitivities of individual genetic markers were 67%-100%, with specificities of 94%-100%. Our 3 conclusions were as follows: (1) EMA, CD99, bcl-2, and claudin-1 IHC and 1p, 14q, NF2, and 4.1B FISH are particularly useful for distinguishing anaplastic meningiomas from meningeal HPCs. (2) Focal EMA expression does not preclude a diagnosis of HPC. (3) The characteristic FXIIIa staining pattern reported for HPC also is encountered frequently in anaplastic meningiomas and therefore is nonspecific in this diagnostic setting.

Enzymohistochemical and immunohistochemical study of the human efferent ducts

An enzymohistochemical and immunohistochemical study of the efferent ducts was performed in normal adult men. The epithelium consists of two types of columnar cells: principal cells (PCs) and ciliated cells (CCs), and is surrounded by a lamina propria (LP) with cells arranged circularly (LPCs). Enzymohistochemical study revealed more intense activity of succinic dehydrogenase, NADP, and ATPase in the CCs than in the PCs. The LPCs also showed an intense reaction for NADP and ATPase. Acid phosphatase activity was only intense in the apical cytoplasm of PCs. Immunohistochemical study revealed that antibodies to oestradiol receptor-related protein (ER-D5) immunostained the PCs and CCs intensely and the LPCs weakly. AE1/AE3 antibodies (which stain keratins nos. 1-8 and 14, 15 and 19) immunostained the PCs intensely, but was negative in both CCs and LPCs. Antibodies to keratin Ks.4.62 (which stain keratin no. 19) immunostained PCs and CCs but not LPCs. Epithelial membrane antigen antibodies (EMA) immunostained the adluminal surface and apical cytoplasm of PCs. Anti-vimentin antibodies immunostained the cytoplasm of PCs and CCs weakly as well as isolated cells in the LP. Antibodies to desmin immunostained most LPCs. Antibodies to collagen IV immunostained the basal lamina and many extracellular spaces in the LP, mainly around the LPCs. The differences between the enzymohistochemical and immunohistochemical patterns of the efferent ducts and those of the epididymis may help to explain functional differences along the epididymis.

Immunohistochemistry of the human ductus epididymis.

Our objective was to characterize epithelial cells, lamina propria, and sites of estrogen coupling in the caput, corpus, and cauda regions of the human epididymis using antibodies to cytokeratin types; epithelial membrane antigen; laminin; type IV collagen; vimentin; desmin-, and estradiol-receptor-related protein; and immuno-histochemical techniques. Principal cells immunostain by both AE1/AE3 antibodies (keratins 1-8, 10, 13-15, and 19) and anti-pan-keratin antibodies (keratin 5, 6, and 8). Immunoreactions to both anti-keratin antibodies increase from the caput to the cauda epididymis. The principal cells only immunostained by anti-keratin 19 antibodies in the cauda and showed no reaction to keratins 10 and 11. Basal cells and apical cells immunoreact to anti-AE1/AE3, antipankeratin, and antikeratin 19 antibodies, but not to antikeratin 10 and 11 antibodies, in all three epididymal regions. The principal cells immunoreact with epithelial membrane antigen antibodies in the stereocilia and subjacent cytoplasm. This immunostaining decreased from the caput to the cauda. Antivimentin antibodies stained the apical cytoplasm of principal cells and limited areas of both principal cells and basal cells. This immunoreaction decreased from the caput to cauda. Apical cells immunostained in the three regions. Immunoreaction to ER-D5 was moderate in the principal cells, basal cells, apical cells, and muscular coat cells in the cauda. The apical cells immunostained in the three regions. Antilaminin antibodies stained the epithelial basement membrane in the three regions. Type IV collagen was detected in the basement membrane as well as around the muscular coat cells in the three regions. Immunoreaction to desmin was intense in the muscular coat cells in the three regions.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative light-microscopic and immunohistochemical study of traumatic and palisaded encapsulated neuromas of the skin.

The primary hyperplastic nature of palisaded encapsulated neuromas (PENs) has been recently challenged by suggesting a traumatic origin. We studied eight cases of traumatic neuroma (TN) and 12 cases of PEN by routine light-microscopic, histochemical, and immunohistochemical methods to assess evidence of previous tissue injury. Sections from the formalin-fixed, paraffin-embedded tissue were stained with hematoxylin-eosin, trichrome, elastic, reticulin, Giemsa, colloidal iron (with and without hyaluronidase), and Bielschowsky silver stains. Antibodies were applied to collagen types I, III, and IV, MAC 387, factor XIIIa, alpha 1-antitrypsin (A1AT), epithelial membrane antigen (EMA), Leu-7, and myelin basic protein using ABC techniques. We found that (a) in TN the individual fascicles were usually surrounded by perineurial cells, whereas in PEN the perineurial cells were observed mainly in the capsular areas and only rarely within the fascicles as evidenced by EMA antibodies; (b) histochemically TN contained considerably larger amounts of collagen (types I and III), acidic mucin, and myelin products than did PEN; and (c) neither PEN nor TN contained increased inflammatory cells or cells positive for factor XIIIa, MAC 387, or A1AT. We conclude that (a) there are substantial structural and histochemical differences between TN and PEN, (b) the changes suggest that the classic form of PEN has a different histogenesis than TN, and (c) on histologic grounds, chronic minor trauma could not be excluded as an etiologic factor for PEN.

The utility of immunocytochemistry in invasive adenocarcinoma of the cervix

The purpose of the study was to evaluate the utility of immunocytochemistry in the management of cervical adenocarcinoma. Patterns of reactivity to various immunocytochemical markers were correlated with clinically known risk factors for recurrence. A retrospective evaluation of 55 patients with invasive cervical adenocarcinoma was conducted. Monoclonal antibodies were generated against various human intermediate filament proteins and tested on fixed, paraffin-embedded tissue by the avidin-biotin complex immunoperoxidase method. Dako V9 antivimentin antibodies and two anticytokeratin antibodies, 35 beta H11 and 34 beta E12, were used. Polyclonal antibodies to carcinoembryonic antigen and antibodies to epithelial membrane antigen were used. Of 55 patients, 50 (91%) had positive epithelial membrane antigen antibodies in tumor cells. Tissue from patients with cervical adenocarcinoma demonstrated positivity for 35 beta H11 antibodies in 46 of 53 patients (87%) and positivity for 34 beta E12 antibodies in 15 of 54 patients (28%). Vimentin antibodies were negative in all except one patient. Carcinoembryonic antigen-positive antibodies were detected in 37 of 55 patients (67%). This study also demonstrated consistent negative expression of vimentin in invasive cervical adenocarcinoma. Carcinoembryonic antigen expression rates were 50% and 75% for patients with small tumors (less than or equal to 2 cm) and large tumors (greater than 2 cm), respectively (p less than 0.01). Patients with carcinoembryonic antigen expression are at increased risk for recurrence and also sustain reduced survival potential. Patients with cervical adenocarcinoma and carcinoembryonic antigen expression are at increased risk for recurrence. We speculate that immunocytochemistry may detect lymph node micrometastases otherwise unsuspected by conventional microscopy.

VASCULAR TUMORS OF THE BRAIN : AN IMMUNOHISTOCHEMICAL STUDY

Fourteen cases with intracranial vascular tumors including 5 hemangioblastomas, 7 hemangiopericytic meningiomas, and 2 hemangioblastic meningiomas were investigated by immunohistochemistry using antibodies against alpha-smooth muscle actin, alpha tubulin, collagen type 4, desmin, epithelial membrane antigen (EMA), fibronectin, cytokeratin AE1/AE3, myosin and vimentin. A positive immunoreactivity for EMA was observed in the tumor cells of hemangioblastic meningiomas. Since other vascular tumors did not react with EMA antibody, EMA immunostaining seemed to be useful for differencing hemangioblastic meningioma from other types of vascular neoplasms. Alpha-smooth muscle actin proved to be an excellent marker of vascular pericytes. Tumor cells of hemangiopericytic meningiomas, however, did not immunostain with alpha-smooth muscle actin antibody. This does not support the theory of a pericytic origin for hemangiopericytic meningioma. Neither an endothelial marker nor a pericytic marker was detected in stromal cells of the hemangioblastomas. The histogenesis of the stromal cells remains to be ascertained.

口腔へん平上皮癌の臨床的，免疫組織学的検討 癌胎児性抗原，上皮膜抗原について

We studied 74 cases of squamous cell carcinoma in the oral cavity, clinico-pathologically and immunohistochemically. Of the 74 cases, primary cervical lymph node metastasis was observed in 19 cases and secondary cervical lymph node metastasis in 8 cases. The materials were obtained before the treatment, fixed in 10% formalin or 2% PLP and embedded in paraffin. Immunostaining of carcinoembryonic antigen (CEA) and epithelial membrane antigen (EMA) was performed by the avidin-biotin peroxidase complex (ABC) method with monoclonal mouse anti-human CEA antibody and anti-human EMA antibody respectively. CEA-and EMA-positive stainings were graded as “slight”, less than 25%, “moderate”: 25-75%, “marked”: more than 75%, judging by stained area in the 100X field.The results showed that the grade of CEA and EMA staining correlated with the degree of epithelial differentiation of the tumor, although EMA was more sensitive marker than CEA. In addition, high frequency of “marked” CEA and EMA expression in no cervical lymph node metastatic cases was observed significantly. However, there was no significant relation between the grade of CEA and EMA stainings and the presence of cervical lymph node metastasis as whole. Thus, by examining these factors, we were unable to satisfactorily predict the presence of cervical lymph node metastasis.

K562 erythroleukemia cells express cytokeratins 8, 18, and 19 and epithelial membrane antigen that disappear after induced differentiation

The effects of differentiation-modulating drugs were studied on the expression of intermediate filaments (IFs) in the human K562 erythroleukemic cell line. The untreated cells contained typical cytoplasmic coiling bundles, positive for both vimentin and cytokeratin as judged by indirect immunofluorescence microscopy with monoclonal antibodies (Mabs). Some of the cells also showed bright immunoreactivity for epithelial membrane antigen (EMA), as revealed with a Mab and polyclonal antiserum. When exposed to hemin or to sodium butyrate, most of the cells became cytokeratin negative within 3 days and showed dispersion of vimentin fibrils. Upon exposure to the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA), the amount of both vimentin and cytokeratin appeared to be greatly increased within 3 days and was found both in dispersed cytoplasmic fibrils, in large spherical, eccentric aggregates, as well as in cytoplasmic fibrils in cells spreading on fibronectin. TPA induced a complete loss of proliferation, as judged by immunostaining with the Mab Ki-67. The effects of TPA were found to be irreversible and could be induced by only a short exposure to the drug. Western blotting analysis and monoclonal antibodies to individual cytokeratins revealed that untreated K562 cells expressed Mr 52,000 (No. 8), 46,000 (No. 18), and 40,000 (No. 19) cytokeratin polypeptides, which disappeared when the cells were exposed to hemin or to sodium butyrate to induce erythroid differentiation but were greatly enhanced when exposed to TPA. The monoclonal anti EMA antibody reacted in K562 cells with a single Mr 320,000 polypeptide that was also revealed in MCF-7 breast carcinoma cells. Human bone marrow cells or other leukemic cell lines with erythroid differentiation capacity (HEL and KG-1) did not contain cytokeratin- or EMA-immunoreactive cells, suggesting that in K562 cells these properties may rather represent abnormal cytodifferentiation or retrodifferentiation toward early embryonic mesenchymal cells, than a more general expression of epithelial features in human leukemic cells.

Segmental neurofibromatosis: Immunocytochemical analysis of cutaneous lesions

Cutaneous lesions from three patients with segmental neurofibromatosis were evaluated. Routine histologic studies revealed the presence of redimentary neural structures within an abundant collagenous matrix. The majority of the cells in all three cases expressed S-100 protein, suggesting their identity as Schwann cells. The stromal component stained positively for fibronectin and type IV collagen; the latter indicated the presence of basement membrane material. Embedded in the tumor mass were glandular epithelial structures that stained with epithelial membrane antigen antibody. Staining for factor VIII-related antigen revealed vascular endothelium and multiple scattered mast cells. In one case strands of cells stained with antibodies to desmin, suggesting muscle cell differentiation. This case may represent a distinct subset of neurofibromas.

Disseminated Syringomas of the Upper Extremities

A case of disseminated syringomas with unusual distribution and high age of onset is reported. The 66-year-old male patient presented with multiple lesions confined to dorsum of both hands and flexor side of both forearms. Morphological and immunohistochemical studies using keratin, S-100, carcinoembryonic antigen, and epithelial membrane antigen antibodies were performed both at light microscopical and ultrastructural level. These investigations revealed the presence of keratin filament containing colloid bodies near syringomatous epithelia. Reactivity for carcinoembryonic antigen could be demonstrated on the membranes of intracytoplasmic vesicles as well as within luminal debris. Absence of S-100 and epithelial membrane antigen in the tumor and ultrastructural features indicate ductal origin of syringoma.

Hamartoma of the Scalp with Ectopic Meningothelial Elements

Five cases of a distinctive benign soft tissue lesion of the scalp in patients ranging from 4 months to 40 years of age are described. Clinically, the lesions appeared as solitary, subcutaneous nodules suggestive of a cystic vascular malformation or other benign condition. Histologically, however, the lesions were characterized by a monotonous, pseudoinfiltrative proliferation of cuboidal epithelioid cells arranged in clusters within the dermis and subcutaneous tissue in intimate association with vessels, adipose tissue, and other connective tissue elements. A prominent feature in all cases was the presence of areas simulating freely anastomosing vascular channels lined by round to spindle-shaped, slightly hyperchromatic epithelioid cells reminiscent of angiosarcoma. Immunohistochemically, these cells were negative for factor VIII-related antigen and Ulex europaeus lectin but were strongly positive with vimentin and epithelial membrane antigen antibodies, this latter being in keeping with the immunohistochemical profile of meningothelial cells. The meningothelial nature of these cells was supported by the electron microscopic demonstration in one case of cells with complex, interdigitating cytoplasmic processes that were joined by scattered cell junctions and contained abundant intracytoplasmic intermediate filaments. The intimate admixture of meningothelial elements with haphazardly arranged connective tissue elements sets these lesions apart from cutaneous meningiomas and warrants their designation as hamartomas with an ectopic meningothelial component.

Immunohistochemical markers of human sebaceous gland differentiation.

Cryostat sections of human skin were stained with monoclonal antibodies to involucrin, a range of cytokeratins, epithelial membrane antigen (EMA), and an ovarian cystadenocarcinoma antibody (OM1) to identify combinations of antibodies that could be used to discriminate between basal and differentiated sebocytes and other cell types present in the pilosebaceous unit. Both the EMA and OM1 monoclonal antibodies specifically recognized differentiated sebocytes. No staining of basal sebocytes or other epidermal cell types was seen. Differentiated (but not basal) sebocytes were also stained by a cytokeratin 10 antibody (LH2). Conversely, the basal sebocytes were recognized by an antibody specific to basal keratinocytes (LH6). Cells of the sebaceous duct stained with both LH2 and LH6 and also with the anti-involucrin monoclonal antibody. Cytokeratin 4 has been detected in sebaceous glands by protein analysis but has not previously been detectable immunohistochemically. We show by immunofluorescence after limited proteolysis that cytokeratin 4 epitopes are distributed in all sebaceous gland cells, including the duct cells.