Immunohistochemical localization of cytokeratins in normal eccrine glands, with monoclonal antibodies in routinely processed, formalin-fixed, paraffin-embedded sections

Lymphoepithelioma-Like Carcinoma of the Skin with Potential for Sweat Glandular Differentiation

Lymphoepithelioma-like carcinoma of the skin (LELCS) is a cutaneous malignancy with histopathological resemblance to lymphoepithelioma of the nasopharynx. Its histogenesis remains unknown, and few cases showing skin appendage differentiation have been reported to date. We present the case of a 77-year-old Japanese male with an asymptomatic red nodule on his left cheek. Because the histopathological study revealed focal growth of tumor cells lacking connections with the epidermis and marked lymphocytic infiltration surrounding the neoplastic cell nests, the case was diagnosed as LELCS. On immunohistological staining, the neoplastic cells were positive for carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), multi-cytokeratin (CK), CK6, CK18, and CK19. On the basis of these results, we suggested that skin appendage differentiation, particularly sweat glandular differentiation, was present in this case.

Development, structure, and keratin expression in C57BL/6J mouse eccrine glands

Eccrine sweat glands in the mouse are found only on the footpads and, when mature, resemble human eccrine glands. Eccrine gland anlagen were first apparent at 16.5 days postconception (DPC) in mouse embryos as small accumulations of cells in the mesenchymal tissue beneath the developing epidermis resembling hair follicle placodes. These cells extended into the dermis where significant cell organization, duct development, and evidence of the acrosyringium were observed in 6- to 7-postpartum day (PPD) mice. Mouse-specific keratin 1 (K1) and 10 (K10) expression was confined to the strata spinosum and granulosum. In 16.5 and 18.5 DPC embryos, K14 and K17 were both expressed in the stratum basale and diffusely in the gland anlagen. K5 expression closely mimicked K17 throughout gland development. K6 expression was not observed in the developing glands of the embryo but was apparent in the luminal cell layer of the duct by 6 to 7 PPD. By 21 PPD, the gland apertures appeared as depressions in the surface surrounded by cornified squames, and the footpad surface lacked the organized ridge and crease system seen in human fingers. These data serve as a valuable reference for investigators who use genetically engineered mice for skin research.

Current progress of immunostains in Mohs micrographic surgery: a review

Mohs micrographic surgery is often considered the treatment of choice for a variety of skin malignancies. In recent years, the application of immunostaining techniques has facilitated the successful removal of a number of common and less common cutaneous malignancies, including basal cell carcinoma, squamous cell carcinoma, malignant melanoma, dermatofibrosarcoma protuberans, microcystic adnexal carcinoma, sebaceous carcinoma, atypical fibroxanthoma, extramammary Paget's disease, and even sarcomas. Immunostains highlight the tumor cells and allow the Mohs surgeons to pinpoint and eliminate the residual tumor at the surgical margin. It is especially helpful when a tumor presents with subtle or nonspecific histologic features or when a tumor is masked in a pocket of dense inflammation. However, the cost, the labor, and the time consumption are of concern to many of our peers, as are the diversity of antigens, which may overwhelm some. This article serves as a review of the literature on current uses of immunostaining in Mohs micrographic surgery and as a summary of their realistic applications in the dermatologic surgeon's practice. We conclude that immunohistochemical technique has played an important role in Mohs surgery advancement. With greater use and more cost-effective staining methods, we believe that the use of immunostains in a Mohs practice will become routine.

Are Sweat Glands an Alternate Penetration Pathway? Understanding the Morphological Complexity of the Axillary Sweat Gland Apparatus

To build an effective barrier against the penetration of extrinsic agents is one of the skin's main functions. The barrier properties of the stratum corneum and the epidermis have been subject to extensive studies in the past while the role of skin appendages as possible pathways of penetration are only rarely described. In order to study the possible penetration barriers in these complex appendages, a careful investigation of their morphology and ultrastructure has to be done. Studying the morphology of axillary skin appendages requires clear-cut criteria for the differentiation between eccrine, apocrine and apoeccrine glands. Therefore we studied the distribution of proteins described to be specific for either eccrine or apocrine glands (CD15, CD44, S-100 and milk fat globulin) on axillary skin samples from healthy young adults by immunofluorescence. Additionally, we examined the distribution of cytoskeletal proteins such as cytokeratins (1/10/11, 14, 18) and F-actin. For a more detailed understanding of the possible versatile barrier elements of the axillary sweat glands, we studied the distribution of tight-junction-associated proteins (occludin, claudin 1, claudin 4). The coils and the dermal duct may provide an active barrier built of tight junctions as occludin and claudin 4 are co-localized. However, the intra-epidermal duct did not show any co-localization of the investigated proteins. By combining morphological features as revealed by F-actin staining and the distribution of the above-mentioned proteins, immunocytochemical typing of eccrine and apocrine glands becomes possible. With this tool, we could also confirm the existence of apoeccrine glands and locate them in their 'natural environment'.

Characterization of a novel human type II epithelial keratin K1b, specifically expressed in eccrine sweat glands

In this study, we show that a novel human type II epithelial keratin, K1b, is exclusively expressed in luminal duct cells of eccrine sweat glands. Taking this luminal K1b expression as a reference, we have used antibodies against a plethora of epithelial keratins to systematically investigate their expression in the secretory globule and the two-layered sweat duct, which was divided into the intraglandular, intradermal, and intraepidermal (acrosyringium) segments, the latter being further subdivided into the sweat duct ridge and upper intraepidermal duct. We show that (i) each of the eccrine sweat gland tissue compartments expresses their own keratin patterns, (ii) the peripheral and luminal duct layers exhibit a sequential keratin expression, with both representing self-renewing cell layers, (iii) the intradermal duct and the sweat duct ridge display hitherto unknown length variations, and (iv) out of all cell layers, the luminal cell layer is the most robust layer and expresses the highest number of keratins, these being concentrated at the apical side of the cells to form the cuticle. We provide evidence that the cellular and intercellular properties of the peripheral and the luminal layers reflect adaptations to different functions.

Human papillomavirus-associated plantar epidermoid cyst related to epidermoid metaplasia of the eccrine duct epithelium: a combined histological, immunohistochemical, DNA-DNA in situ hybridization and three-dimensional reconstruction analysis

BACKGROUND

We recently proposed that certain palmoplantar epidermoid cysts may be related to eccrine ducts and that human papillomavirus (HPV) 60 may play a role in their pathomechanism. However, the origin of palmoplantar epidermoid cysts is still controversial.

OBJECTIVES

To examine the contribution of eccrine ducts and HPV 60 in the development of epidermoid cysts.

METHODS

Five epidermoid cysts and four ridged warts that had developed on the soles of a patient were studied histologically, immunohistochemically and by DNA-DNA in situ hybridization. Using serial sections obtained from its entire body, a three-dimensional reconstruction (3DR) analysis was performed on the smallest cyst to analyse the relationship between the epidermoid cyst, eccrine duct and the overlying epidermis.

RESULTS

Histological and DNA-DNA in situ hybridization analyses demonstrated both homogeneous intracytoplasmic inclusion bodies pathognomonic for HPV 60 infection and HPV 60 DNA sequences not only in all of the epidermoid cysts and ridged warts but also in the acrosyringeal portion of an eccrine duct, with the dermal portion of which the smallest cyst had been revealed to connect by 3DR analysis. However, immunohistochemical analyses using antibodies against human carcinoembryonic antigen (CEA), involucrin and several cytokeratins (CKs) revealed that the immunoreactivity of the cyst was not identical to that of the eccrine dermal duct but was identical to that of suprabasal layers of the epidermis.

CONCLUSIONS

It was clearly demonstrated that an HPV 60-associated epidermoid cyst with immunoreactivities for CEA, involucrin and CKs which were identical to those of the epidermis connected with the eccrine dermal duct, supporting the idea that certain palmoplantar epidermoid cysts may develop following the epidermoid metaplasia of eccrine ducts with HPV 60 infection.

Differentiation of Hidroacanthoma Simplex from Clonal Seborrheic Keratosis-An Immunohistochemical Study

Hidroacanthoma simplex (HS) is an uncommon poroid neoplasm confined within the epidermis. The clinical features of HS are not distinctive and histopathologically HS may be confused with clonal seborrheic keratosis (CSK) if cystic or ductal structure is not present. The purpose of our study was to differentiate HS from CSK by the immunohistochemical expressions of various cytokeratins, CEA, CD1a, and S-100 protein, as well as by the degrees of deposition of melanins and glycogen. Four cases of HS and seven cases of CSK were included in the research. In contrast with CSK, HS showed a very low density of Langerhans cells (19.9 +/- 7.7 versus 3.1 +/- 1.0 CD1a (+) cells/mm, P = 0.027) and sparse melanin deposition in the nests. However, HS could not be set apart from CSK by the expressions of cytokeratins. The nests of both HS and CSK showed very similar patterns of cytokeratin expression and seemed to be mainly composed of basaloid cells with focal differentiation toward epidermal suprabasal cells.

Keratinocytes can differentiate into eccrine sweat ducts in vitro: involvement of epidermal growth factor and fetal bovine serum

BACKGROUND

in addition to formation of an epidermal sheet and dermal substitution, reconstruction of skin that possesses functionality is an important goal for dermatologists.

OBJECTIVE

we attempted to regenerate eccrine sweat glands in vitro.

METHODS

we constructed skin equivalent models with various combination of normal human keratinocytes and fibroblasts and also examined the effect of various growth factors.

RESULTS

we found that keratinocytes invaded the collagen gels and formed eccrine duct-like structures, only when (i) the culture media contained at least 15 ng/ml of epidermal growth factor (EGF) and fetal bovine serum (FBS), (ii) the keratinocytes were derived from young donors, and (iii) fibroblasts were present in the gel. Interestingly, when cultured under the same conditions eccrine gland duct cells were unable to invade the gel. Immunohistochemical analyses revealed induction of carcinoembryonic antigen by EGF at the inner part of the eccrine duct-like structures. Proliferating cell nuclear antigen was expressed mainly in basal layers of the epithelia but was not observed in the deeply invaded part. Cytokeratin profiles of the reconstructed epithelia were consistent with those of the regenerating epidermis and partly with the eccrine sweat duct.

CONCLUSIONS

although not perfect model, these results indicate that 'young' keratinocytes could differentiate into/toward eccrine sweat ducts in vitro in the presence of EGF and FBS in cooperation with dermal fibroblasts.

Syringoid eccrine carcinoma: report of a case with immunohistochemical analysis of cytokeratin expression

Syringoid eccrine carcinoma is an extremely rare cutaneous malignant tumor, thought to be derived from eccrine sweat apparatus. We report a case of syringoid eccrine carcinoma occurring on the scalp of a 66-year-old woman and analyzed its cytokeratin expression immunohistochemically to clarify its histogenesis. The tumor consisted mainly of numerous small cords and nests extending from the reticular dermis to the subcutaneous tissue, which formed luminal or tubular structures mimicking the nests of syringoma. Immunohistochemical analysis revealed that most tumor cells expressed simple epithelial cytokeratins (CKs 7, 8, 18, 19) suggesting their sweat secretory differentiation, and that a small number of tumor cells showed an expression of stratified epithelial cytokeratins (CKs 5, 14) suggesting their ductal differentiation. We believe that the syringoid eccrine carcinoma of our case may differentiate mainly toward the sweat secretory cells rather than toward the dermal ductal cells.

Immunohistochemical analysis of cytokeratin and human milk fat globulin expression in mucinous carcinoma of the skin

BACKGROUND

Mucinous carcinoma of the skin (MCS) is a rare epithelial tumor which arises primarily in the skin. Metastatic MC from extracutaneous sites, especially breast or colon, mimics MCS and cannot be differentiated from MCS by routine histology alone.

METHODS

Nine cases of MCS were analyzed immunohistochemically using monoclonal antibodies against cytokeratins (CKs) and human milk fat globulin 1 (HMFG) in order to clarify their nature and compare the immunophenotypes with those of other MCs studied in the literature.

RESULTS

Expression of simple epithelial CKs in most of the tumor cells of all cases studied and co-expression of simple and stratified epithelial CKs in some tumor cells of two cases were recognized. CK 20 expression could not detected in any tumor cells. Focal HMFG expression in the luminal or outer surface of the nests was observed in three cases.

CONCLUSION

From CKs expression, MCS was speculated to differentiated mainly toward the secretory cells of the sweat glands, and some tumor cells toward the transient portion between the dermal duct and the secretory portion. Focal HMFG expression suggested either a consequence of malignant transformation or apocrine differentiation. No expression of CK 20 in MCS suggests that we may exclude the diagnosis of metastatic colorectal MC which expressed CK 20.

Clear cell papulosis: an immunohistochemical study to determine histogenesis

Clear cell papulosis is a rarely described disease characterized by multiple white maculopapules. Histopathologically, diagnostic clear cells are seen mainly among the basal cells of the epidermis. The origin of the clear cells has been thought to be eccrine or apocrine secretory cells in the epidermis because of the positive immunostaining with anticytokeratin antibody AE1, carcinoembryonic antigen (CEA), epithelial membrane antigen, and gross cystic disease fluid protein-15. IKH-4 and CEA have been reported to stain the eccrine secretory cells, but not the apocrine secretory cells. On the contrary, lysozyme has been reported to stain apocrine glands, but not eccrine glands. CAM5.2 has been reported to show a positive reaction to staining in secretory cells of eccrine glands, but only occasional weak staining in the inner surface of eccrine ducts. In our study, the clear cells in the epidermis stained with IKH-4, CEA and CAM5.2, but not with lysozyme. These results suggest that the clear cells may be eccrine secretory cells.

Characterization of interdigital glands in the Asian elephant (Elephas maximus)

In the Asian elephant, wetness akin to perspiration is commonly observed on the cuticles and interdigital areas of the feet; this observation has lead to speculation regarding the existence of an interdigital gland. Our goal was to search for interdigital glands and characterise them morphologically, histochemically, and immunohistochemically. Necropsy samples of interdigital areas from two Asian elephants were obtained. Multiple sections were fixed and processed routinely, then stained with hematoxylin/eosin and differential mucin stains. Immunohistochemistry was also performed for cytokeratins 8 and 10. Interdigital glands resembling human eccrine glands were detected deep within the reticular dermis. Histochemical staining indicated neutral mucopolysaccharides and nonsulphated acid mucopolysaccharides in glandular secretions, and the glandular epithelium also showed immunoreactivity to cytokeratins 8 and 10. Both the histochemical and immunohistochemical staining patterns are analogous to human eccrine structures. This study shows with certainty that Asian elephants possess sweat glands as they are defined histologically.

Immunohistochemical observation of cytokeratins in keratinous cysts including plantar epidermoid cyst

Sixteen cases of epidermal cyst (EC) (6 cases of conventional EC and 10 cases of plantar epidermoid cyst (PEC)) and 9 cases of trichilemmal cyst (TC) were examined by an immunohistochemical technique using various antibodies against cytokeratins and human papilloma virus (HPV) in order to clarify their histogenesis. There was no difference in immunoreactivities between EC and PEC with or without HPV infection. In TC, the inner layers of the cyst wall were stained with the antibody E3 (CK17), and the outermost layer was stained with the antibodies 4.1.18 (CK8) and 170.2.14 (CK19). In PEC and EC, however, the cyst wall didn't react with these antibodies, and differentiation-specific cytokeratins were expressed in the inner layer. These results confirmed that the immunoreactivities of PEC and EC were identical to those of normal epidermis or infundibulum, and that those of TC were similar to the outer root sheath between the lower infundibulum and isthmus. Although PEC has been recently reported to originate from eccrine ducts, there was a significant difference in immunoreactivities between PEC and eccrine ducts. Furthermore, on the basis of the fact that sole skin has no hair follicles, PEC was speculated to originate from epidermal implantation.

Immunohistochemical analysis of cytokeratin expression in apocrine cystadenoma or hidrocystoma

Apocrine cystadenoma is a benign sweat gland tumor which consists of various histologic types of epithelium: epithelium with decapitation secretion, pseudostratified epithelium, and flattened epithelium. Immunophenotypes, especially the expression of cytokeratins, in 8 cases of this tumor were examined immunohistochemically, because the nature or differentiation of each epithelium is not well known. The following antibodies were used as primary antibodies: those against involucrin, smooth muscle actin, and human milk fat globulin respectively, and 15 kinds of monoclonal anti-cytokeratin antibodies. Although the staining pattern varied from case to case according to the proportion of each epithelium, these epithelia, except for the flattened epithelium, revealed invariable staining patterns. The staining pattern in the epithelium with decapitation secretion and the pseudostratified epithelium was similar to that in the secretory portion including myoepithelial cells and the junction of the excretory ductal portion with the secretory portion, respectively. However, the flattened epithelium, probably due to intraluminal pressure, showed various staining patterns similar to that in each portion of the apocrine gland. Based on the above observations, we confirmed that apocrine cystadenoma was a complex tumor differentiating into each portion of the apocrine gland, i.e. the dermal duct, the junction of the excretory ductal portion with the secretory portion, and the secretory portion.

Immunohistochemical analysis of cytokeratin expression in multiple eccrine hidrocystoma

The histologic diagnosis as eccrine hidrocystoma may contain some other cysts which do not originate from the eccrine sweat glands. Some authors have suggested that true eccrine hidrocystoma does not exist. However, multiple eccrine hidrocystoma (Robinson type) is a distinct clinical entity which is characterized by multiple translucent papules around the eyelids which appear in warm weather. Cytokeratin expression in 8 cases of multiple type of unequivocal eccrine hidrocystoma was analyzed immunohistochemically. Immunoreactivities in our cases were similar to those of eccrine dermal ducts. Therefore, we confirmed that these tumors were derived from the eccrine dermal duct, not from the other appendages, and that true eccrine hidrocystoma exists.

Palmoplantar pustulosis: a clinical and immunohistological study

Pustulosis palmoplantaris (PPP) is a common chronic skin disease, which is very resistant to treatment. It is not known why the lesions are located in the palms and soles. There are few studies of the disease and in particular studies of the histology. Fifty-nine patients with PPP answered a questionnaire concerning their medical history and 39 of them were clinically examined. Biopsy specimens were taken from involved skin in 22 of the 39 patients and studied immunohistologically for tryptase+ mast cells, EG2+ eosinophils, lipocalin+ neutrophils and CD3+ T lymphocytes. The sweat gland and sweat duct were visualized with AE1/AE3 antibody (cytokeratins 1-8, 10, 14/15, 16, 19). In addition to neutrophils in the pustule and lymphocytes in the upper dermis, there were also large numbers of mast cells and eosinophils in the subpustular area. Numerous eosinophils were present in the pustule. The epidermal part of the eccrine duct was not detectable in any of the specimens from patients with PPP but was present in all of the nine control persons (including two smokers). The results indicate that the acrosyringium is involved in the inflammation and also that mast cells and eosinophils participate in a hitherto unknown way. Of the 39 patients clinically examined, two had previously diagnosed thyroid disease and two had gluten hypersensitivity. Seventeen had one or several abnormal serum concentrations of thyroid-stimulating hormone, thyroxin, antibodies against thyroglobulin or thyroperoxidase and 10 had immunoglobulin (Ig) A antibodies to gliadin. The mean +/- SD for serum IgA and for eosinophil cationic protein was increased. From the questionnaire the most notable finding was that 56 of the 59 patients had been or still were smokers, all of whom had started smoking before the first signs of PPP. We hypothesize that the acrosyringium might be the target for the inflammation and that PPP is linked to autoimmune thyroid disease and smoking.

Papillary tubular adenoma with marked tubular vacuolization

We report a case of papillary tubular adenoma, arising on the knee joint. The overall histologic structure of the tumor is consistent with that of papillary tubular adenoma with slight interluminal papillary changes, but most of the tumor cells present vacuolization outlined by carcinoembryonic antigen staining, suggesting that this adenoma may have resulted from microlumen formation. This is, to our knowledge, the first reported case of a papillary tubular adenoma with marked tubular vacuolization.

Histogenesis of mixed tumor of the skin, apocrine type: immunohistochemical study of keratin expression

To investigate the histogenesis of mixed tumor of the skin, apocrine type, the immunophenotypes of 10 cases were examined using 19 different monoclonal anti-keratin antibodies and antibodies against carcinoembryonic antigen (CEA) and involucrin. By using light microscopy, four epithelial elements in this tumor were characterized: tubular branching structures with lumina lined by cuboidal epithelium and those with lumina lined by columnar epithelium, keratinous cysts, and solid aggregates of epithelial cells. The immunohistochemical patterns of cytokeratin expression suggested that cuboidal and columnar cells differentiated, respectively, toward the ductal and secretory cells of apocrine glands, whereas keratinous cysts revealed follicular infundibular differentiation. Furthermore, CEA expression, a marker for sweat-gland differentiation, was present not only on tubules' luminal surfaces but also on the inner surfaces of keratinous cysts. The simultaneous coexpression of CEA and cytokeratins specific for follicular infundibulum in the keratinous cysts, although perplexing, suggested that keratinous cysts may contain some cells differentiating toward the intrafollicular portion of apocrine ducts that enter infundibulae rather than eccrine ducts that have no infundibular association. We conclude that apocrine type of mixed tumors of the skin demonstrate differentiation toward all components of apocrine units.

Papillary eccrine adenoma: immunohistochemical studies of keratin expression

Despite various studies, there are serious disagreements about the cellular differentiation of papillary eccrine adenoma. In the present study, 2 specimens of papillary eccrine adenoma were analyzed by immunohistochemical techniques, using a panel of monoclonal antibodies against keratins, to elucidate its differentiation. Histopathologically, the tumor was composed of multiple tubular structures lined by two or more layers of epithelial cells. The luminal cells of the tubules were flattened or cuboidal. The former were noted in large dilated tubules. The latter were usually observed in small-to-moderate-sized tubules, and formed intraluminal papillary projections in some tubules. Immunohistochemically, there were two kinds of cuboidal cells in the luminal layers of the tubules. Most of the large dilated tubules and some of the small-to-moderate-sized tubules expressed immunophenotypes similar to those of the eccrine dermal duct. The other tubular structures, including the small tubules resembling those of syringoma, expressed immunophenotypes similar to those of the transitional portions between the dermal ducts and the secretory segments of eccrine glands. From the above comparative studies, papillary eccrine adenoma is considered to differentiate towards the dermal duct and the transitional portions between the dermal ducts and the secretory segments of eccrine glands.

Immunohistochemical analysis of keratin expression in clear cell syringoma. A comparative study with conventional syringoma

Immunophenotypes, especially expression of cytokeratins, in 9 cases of clear cell syringoma were examined using antibodies against epithelial membrane antigen (EMA), and 17 kinds of monoclonal anti-keratin antibodies to investigate its histogenesis. In addition, 7 cases of conventional syringoma were selected for parallel assessment. Conventional syringoma expressed CK1 and CK10, which exists in the acrosyringium and the transitional portion between the acrosyringium and the dermal duct. Based on immunostaining with RCK102 and 35 beta H11, syringoma was thought to express CK5. Because expression of CK5 was observed in the basal cells of sweat duct ridge (lower acrosyringium) and the outer cells of the dermal duct, but not in the acrosyringium located at upper epidermis, we speculated that syringoma differentiated toward the transitional portion between the acrosyringium and the dermal duct. A comparative study of keratin expression between conventional and clear cell syringoma showed that there was no difference in the immunoreactivities. Based on the above observations, we confirmed that clear cell syringoma is a metabolic variant of conventional syringoma, and differentiates into the transitional portion between the acrosyringium and the dermal duct.

Histogenesis of clear cell hidradenoma: immunohistochemical study of keratin expression

The expression of cytokeratins in 10 cases of clear cell hidradenoma, including 3 cases of solid cystic hidradenoma, were examined using 21 kinds of monoclonal antibodies. We divided them into three histologic patterns: massive nests with a few lumina (M nests), nests with some tubular lumina (L nests), and nests in solid cystic hidradenomas (S nests). All hidradenomas showed similar immunoreactivities to those in the lower dermal ducts or secretory cells of normal eccrine glands. With antibodies against simple epithelial cytokeratins (CKs 7, 8, 18, and 19), however, different immunostaining was noted among the three histologic patterns. Namely, the M nests failed to react to them, although some luminal cells in the L nests revealed a positive staining. Furthermore, a majority of luminal cells in the S nests revealed a positive staining with them. Therefore, we think that the luminal cells in solid cystic hidradenoma mainly differentiate toward the secretory cells, and that the M nests mainly differentiate toward the dermal duct. Those in the L nests are thought to differentiate toward the dermal duct and the secretory cells. The proportion of the differentiation toward luminal cells of dermal ducts to the differentiation toward secretory cells was the main difference among the three nests. In addition, there was no difference in immunophenotypes between clear cells and epidermoid cells in the two kinds of hidradenomas.

Trichoblastic fibroma. A case report and an immunohistochemical study of cytokeratin expression

A 47-year-old woman noticed a nodule on her right shoulder that had been gradually increasing in size without symptoms. Histologic features of the biopsied nodule included round to irregularly shaped epithelial lobules demarcated by abundant sclerotic stroma located within the lower dermis and extending to the subcutis. The epithelial lobules consisted of cuboidal to columnar basaloid cells and were frequently arranged in narrow strands with many bifurcations and branching. Cystic structures containing lamellar keratinous material were occasionally found in connection with the lobules. The histologic findings were interpreted as trichoblastic fibroma. Immunohistochemical studies with antibodies directed against cytokeratins (CK) and involucrin revealed positive staining in most of the tumor cells with RCK102 and 34 beta E12 antikeratin antibodies, whereas the epithelial cords and the peripheral cells of the cystic structures stained with 170.2.14, 4.1.18, and CAM 5.2 antikeratin antibodies. However, CK1 or simple epithelial cytokeratins were not detected in any neoplastic elements. Based on comparative immunohistochemical findings in normal hair follicles, we propose that trichoblastic fibroma may first differentiate toward the outermost cell layer of the outer root sheath between the lower permanent portion and the upper transient portion and then into various other parts of the hair follicle.

Eccrine syringofibroadenoma (Mascaro). An ultrastructural and immunohistochemical study

Eccrine syringofibroadenoma is a rare benign skin tumor, which usually develops on the extremities of elderly persons. We performed immunohistochemical and ultrastructural studies of a typical case of eccrine syringofibroadenoma that developed on the left heel of a 58-year-old man. The tumor consisted of anastomosing thin epithelial strands connected to the epidermis. There were many ductal or cystic structures, and their luminal cells were strongly positive to antibodies against carcinoembryonic antigen and epithelial membrane antigen. Filagrin and involucrin immunoreactivities were also detected in some cells surrounding the ducts. Keratins K1 and K10, co-expressed in the peripheral cells of normal acrosyringia, were colocalized in small cell clusters. Ultrastructurally, intracellular duct formation characteristic of developing acrosyringia was observed. Tumor cells containing globular keratohyaline granules with various electron densities were seen around some ductal structures. In these areas, keratinization took place without lamellar granule formation or prominent cornified cell envelope assembly. These results suggest acrosyringial differentiation of this tumor.

Epithelial markers and differentiation in adnexal neoplasms of the skin: an immunohistochemical study including individual cytokeratins

Applying immunohistochemical procedures for the detection of eight different cytokeratin (CK) polypeptides and other differentiation markers, we compared the staining patterns of normal cutaneous structures with those of benign adnexal tumors (n = 65). Syringomas exhibited a marker pattern highly reminiscent of that seen in normal dermal eccrine ducts (EMA in peripheral cells, CK 10 in intermediate cells, and CK 6, CK 19, and CEA in luminal cells). Nodular hidradenomas exhibited complex patterns suggesting relationship between tumor cells, including clear cells, and normal secretory coil cells (CK 7, CK 8, CK 19, and EMA); however, dermal-duct and epidermoid differentiation were also detectable. In both cylindromas and spiradenomas, zonal staining patterns were apparent: modified myoepithelial cells were positive for smooth-muscle-type actin, while the luminal cells mainly expressed ductal markers (CK 6 and CK 19) and, less prominently, secretory-coil markers including CK 7. Eccrine poromas exhibited a widespread reaction for CK 5/6 and EMA, analogous to peripheral dermal duct cells, but focal maturation toward inner-ductal and secretory-coil cells was also demonstrable. The staining pattern observed in trichoepitheliomas resembled that of the outer but not the inner root sheath. In conclusion, the detailed marker profiles obtained in the present study have broadened our understanding of the differentiation and nature of these highly singular tumor types.

Eccrine syringofibroadenoma. Report of a case and immunohistochemical study of keratin expression

We report a 49-year-old woman with an eccrine syringofibroadenoma. An asymptomatic nodule appeared on the right heel, and subsequently enlarged gradually. Histological examination revealed anastomosing strands of pale epithelial cells, with occasional duct formation and mucinous fibrovascular stroma. There were two types of strands: thick and thin. Immunohistochemical study, using a panel of monoclonal antikeratin antibodies, revealed that the immunoreactivity differed between the two types of strands. The thick strands showed a staining pattern similar to the uppermost portion of the intradermal duct, and the thin strands showed a pattern similar to the other portion of the duct. This observation suggests that the thick and thin strands differentiate towards the uppermost portion and the remainder of the duct, respectively.

Changes of cytokeratin and involucrin expression in squamous cell carcinomas of the skin during progression to malignancy

The detection of cytokeratins in neoplastic tissues by immunohistochemical methods has numerous diagnostic and investigative applications, because cytokeratins are usually conserved in tumour cells during malignant transformation. Recently, however, it has been reported that progression to malignancy is associated with commencement of expression of low-molecular-weight cytokeratins. In the present study, 42 specimens from 35 cases of squamous cell carcinoma (SCC) of the skin were analysed by immunohistochemical techniques, using polyclonal anti-involucrin antibody and a panel of monoclonal antikeratin antibodies, in order to investigate the nature and differentiation of SCCs. The expression of cytokeratins and involucrin in well-differentiated SCCs was similar to that in normal epidermis. In contrast with well-differentiated SCCs, the expression of differentiation-specific cytokeratins and involucrin was diminished in the immature tumour cells in proportion to the malignancy of the SCCs. Some antibodies, however, stained all tumour cells, irrespective of the degree of malignancy. Furthermore, expression of simple epithelial and non-cornifying stratified squamous epithelial cytokeratins was observed in atypical tumour cells of poorly differentiated SCCs. It is of interest that similar expression was noted in many tumour cells in the lymph node metastases and in some tumour cells in the primary cutaneous lesions. Cytokeratin expression similar to that in normal epidermal keratinocytes was conserved in well-differentiated SCCs, but the expression of cytokeratins changed during progression to malignant transformation. The expression of simple epithelial or non-cornifying stratified squamous epithelial cytokeratins in cutaneous SCCs may be a marker for their capability of invasion and metastatic potential.

So-called mixed tumor of the skin on the wrist: an immunohistochemical study

A case of so-called mixed tumor of the skin arising on the wrist was reported. Immunohistochemical staining of keratins of several molecular weights (AE1/AE3, RCK102, NCL-5D3 and 35 beta H11), carcinoembryonic antigen (CEA), S-100 protein, and desmin was performed. AE1/AE3 and RCK102 were positive in all the tumor cells; CEA, NCL-5D3 and 35 beta H11 were positive mainly in luminal cells of the tubuloalveolar structures. S-100 protein was positive in peripheral cells of the tubular lumina and in scattered cells in the mucous stroma. Desmin was negative in all the tumor cells. Immunohistochemical findings lent further support to the hypothesis that so-called mixed tumor of the skin differentiates into the secretory and ductal portions of the sweat gland.

Cutaneous histopathology of Conradi-Hunermann syndrome

The histopathology of the skin in the ichthyosiform erythroderma associated with classical Conradi-Hunermann syndrome has been rarely described. Skin biopsies from 2 infants with the classical features of Conradi-Hunermann syndrome including ichthyosiform erythroderma contained hyperkeratosis, dilated ostia of pilosebaceous structures, and calcium salts in the stratum corneum detectable with special stains. An unusual feature of one case was dilatation of acrosyringeal structures. We hypothesize that dilatation of acrosyringeal structures is analogous to the plugging noted in pilosebaceous units. Taken together, the ichthyosiform erythroderma of Conradi-Hunermann has a distinctive histologic appearance.

Immunohistochemical analysis of cytokeratin expression in eccrine spiradenoma: similarities to the transitional portions between secretory segments and coiled ducts of eccrine glands

Despite light and electron microscopic and histochemical studies, there is no consensus on the cellular differentiation of eccrine spiradenoma. In the present study, eight specimens of eccrine spiradenoma were analysed by immunohistochemical techniques, using a panel of monoclonal antibodies against cytokeratins. Two types of epithelial cells were identified in tumour nodules: large, pale epithelial cells in the centre, and small, dark epithelial cells situated at the periphery. These nodules frequently contained tubular structures lined by cuboidal, columnar or, less commonly, flattened epithelial cells. Cytokeratin expression in eccrine spiradenoma was compared with expression in normal eccrine glands. Immunohistochemistry revealed that large, pale epithelial cells expressed immunophenotypes similar to those of luminal cells in the transitional portions between the secretory portions and the coiled ducts. The small, dark cells expressed immunophenotypes similar to those of basal cells in the transitional portions. Tubular structures observed in eccrine spiradenoma showed staining patterns similar to those of the luminal cells in the transitional portions. Eccrine spiradenoma may, therefore, differentiate towards the transitional portions between the secretory portions and coiled ducts of eccrine glands. Some of the large, pale epithelial cells in eccrine spiradenoma differentiate towards tubular structures, forming a lumen lined by a cuticle.

Usefulness of the AMeX method for immunostaining with antikeratin antibodies

We performed an immunohistochemical study with 11 antikeratin antibodies using the newly developed AMeX (acetone-methylbenzoate-xylene) tissue processing method. Specimens processed with this method showed almost as good preservation and morphological detail as routinely processed, formalin-fixed and paraffin-embedded tissue specimens, and as good preservation of antigenicity as fresh frozen tissue specimens. Thus, we propose the wide use of this method in dermatology.

Immunohistochemical localization of cytokeratins and involucrin in calcifying epithelioma: comparative studies with normal skin

The expression of cytokeratins and involucrin varies greatly in different epithelia, and this raises the possibility that detailed analysis of these epidermal proteins might provide a means of identifying various skin tumours. The present study was conducted to determine the immunohistochemical distribution of cytokeratins and involucrin in calcifying epithelioma of Malherbe, in order to elucidate the nature and differentiation of this tumour. To correlate the immunohistochemical profile with the most frequent histological patterns, we categorized the basophilic, transitional, shadow, and squamoid cells, and the shreds of keratin. Comparative studies with normal skin showed that the shadow and transitional cells corresponded to hair cortex cells, the squamoid cells to the outer root sheath, the basophilic cells adjacent to the stroma to the outermost cell layer of the outer root sheath between the lower permanent portion and upper transient portion of the follicles, and the basophilic cells adjacent to the transitional cells to the hair matrix. The expression of cytokeratins in most shreds of keratin was similar to that in squamoid cells. Calcifying epithelioma was, therefore, shown to be composed of tumour cells differentiating into both the hair cortex and outer root sheath. These tumour cells were differentiated from basophilic cells, which showed the same staining patterns as the outermost cell layer of the outer root sheath between the lower permanent portion and upper transient portion of the hair follicles, supporting the hypothesis that the keratinocytes in the outermost cell layer can differentiate into the transitional portion of the follicle and anagen hair.

Immunohistochemical distribution of keratin proteins in feline tissues

The immunohistochemical distribution pattern of some keratin intermediate filament proteins has been analysed in a wide range of formalin fixed, paraffin embedded feline tissues using one polyclonal and two monoclonal antibodies raised against human keratins by means of the avidin-biotin-peroxidase complex technique. Only the epithelial and mesothelial cells were stained by the three antibodies, but differences in their corresponding staining pattern were noticed. The staining reaction of the polyclonal antibody raised against human skin keratin was found in both stratified and complex epithelia, while that of the monoclonal antibody which recognizes human keratins 8 + 18 + 19 of the Moll catalogue (NCL-5D3) was restricted to some simple epithelia. The staining reaction of the monoclonal antibody which reacts with human keratins 5 + 8 of the Moll catalogue (RCK-102) covered the widest spectrum of feline epithelial tissues analysed, including stratified, complex and simple epithelia. These staining patterns of feline tissues are basically similar with respect to those of corresponding tissues in other mammalian species, although some differences were also noticed and some obvious epithelial tissues were not stained. This study confirms the broad interspecies cross-reactivity of keratin proteins antibodies and demonstrates their capability to differentiate between various types of feline epithelia and some epithelial compartments.

A comparative study of cytokeratin expression in Paget cells located at various sites

BACKGROUND

Extramammary Paget disease appears in anogenital, axillary, or other areas. In this study, the authors addressed the question of whether the histogenesis of 35 cases of Paget disease arising at different sites was the same.

METHODS

Specimens of 35 cases of extramammary Paget disease (16 genital; 9 invasive carcinomas of genital; 6 axillary; 1 periumbilical; and 3 perianal), 4 cases of mammary Paget disease, 4 cases of breast carcinomas, and 6 cases of anal carcinomas of perianal spread from primary rectal adenocarcinomas were retrieved and stained by the avidin-biotin-complex method, using various kinds of monoclonal antikeratin antibodies.

RESULTS

There was no significant difference in cytokeratin expression among these cases of extramammary Paget disease. Simple epithelial keratins were expressed in Paget cells in extramammary Paget disease, but no expression of differentiation-specific or noncornifying stratified squamous epithelial keratins was observed, regardless of the degree of invasion. Paget cells in extramammary Paget disease revealed a similar cytokeratin expression to that in secretory cells of normal apocrine or eccrine glands. In addition, there was no significant difference in cytokeratin expression in tumor cells among extramammary and mammary Paget disease, breast carcinomas, and anal carcinomas.

CONCLUSIONS

Cases of Paget disease arising at different locations could not be distinguished from each other based on cytokeratin expression. In addition, antikeratin antibodies against simple epithelial keratins were demonstrated to be more useful for the identification of Paget cells in the paraffin sections than were conventional antibodies, such as an antibody against carcinoembryonic antigen (CEA).