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

Comparison of Immunohistochemical Expression of Cytokeratin 19, c-KIT, BerEP4, GATA3, and NUTM1 Between Porocarcinoma and Squamous Cell Carcinoma

ABSTRACT

Distinguishing porocarcinoma from squamous cell carcinoma (SCC) is clinically significant; however, differential diagnosis can often be challenging. This study sought to confirm the diagnostic utility of cytokeratin 19, c-KIT, BerEP4, GATA3, and NUTM1 immunohistochemistry in distinguishing porocarcinoma from SCC. Immunohistochemical analysis of cytokeratin 19, c-KIT, BerEP4, GATA3, and NUTM1 in 14 porocarcinomas and 22 SCCs was performed; the extents and intensities of expression of these markers were recorded. The statistical associations of the immunoexpression between porocarcinoma and SCC were analyzed using the Pearson χ2 test. Cytokeratin 19 was positive in 13 (92.9%) of 14 porocarcinomas, and for all the positive cases, staining was strong and evident in >20% of the tumor cells. By contrast, 9 (40.9%) of 22 SCCs expressed cytokeratin 19 (P = 0.0018), of which 6 showed extremely focal (≤10% of the tumor cells) expression. Of the 14 porocarcinomas, 11 (78.6%) cases showed c-KIT positivity, whereas only 3 of 22 SCCs (13.6%) expressed c-KIT focally (P = 0.0001). In addition, BerEP4 immunostaining differed between porocarcinomas and SCCs (57.1% vs. 9.1%, respectively; P = 0.0017). However, no significant difference between the groups was reported in terms of GATA3 expression (57.1% vs. 72.7%, respectively; P = 0.3336). NUTM1 was expressed in 4/14 (28.6%) porocarcinomas but not in the SCCs. Immunohistochemistry for cytokeratin 19, c-KIT, and BerEP4 could be helpful in distinguishing porocarcinomas from SCCs. In addition, NUTM1 immunoexpression is highly specific, although not sensitive, to porocarcinomas. GATA3 immunohistochemistry has no meaningful implications in the differential diagnosis of porocarcinoma and SCC.

An Algorithmic Immunohistochemical Approach to Define Tumor Type and Assign Site of Origin

Immunohistochemistry represents an indispensable complement to an epidemiology and morphology-driven approach to tumor diagnosis and site of origin assignment. This review reflects the state of my current practice, based on 15-years' experience in Pathology and a deep-dive into the literature, always striving to be better equipped to answer the age old questions, "What is it, and where is it from?" The tables and figures in this manuscript are the ones I "pull up on the computer" when I am teaching at the microscope and turn to myself when I am (frequently) stuck. This field is so exciting because I firmly believe that, through the application of next-generation immunohistochemistry, we can provide better answers than ever before. Specific topics covered in this review include (1) broad tumor classification and associated screening markers; (2) the role of cancer epidemiology in determining pretest probability; (3) broad-spectrum epithelial markers; (4) noncanonical expression of broad tumor class screening markers; (5) a morphologic pattern-based approach to poorly to undifferentiated malignant neoplasms; (6) a morphologic and immunohistochemical approach to define 4 main carcinoma types; (7) CK7/CK20 coordinate expression; (8) added value of semiquantitative immunohistochemical stain assessment; algorithmic immunohistochemical approaches to (9) "garden variety" adenocarcinomas presenting in the liver, (10) large polygonal cell adenocarcinomas, (11) the distinction of primary surface ovarian epithelial tumors with mucinous features from metastasis, (12) tumors presenting at alternative anatomic sites, (13) squamous cell carcinoma versus urothelial carcinoma, and neuroendocrine neoplasms, including (14) the distinction of pheochromocytoma/paraganglioma from well-differentiated neuroendocrine tumor, site of origin assignment in (15) well-differentiated neuroendocrine tumor and (16) poorly differentiated neuroendocrine carcinoma, and (17) the distinction of well-differentiated neuroendocrine tumor G3 from poorly differentiated neuroendocrine carcinoma; it concludes with (18) a discussion of diagnostic considerations in the broad-spectrum keratin/CD45/S-100-"triple-negative" neoplasm.

CD34 and BerEP4 Are Helpful to Distinguish Basaloid Tricholemmoma From Basal Cell Carcinoma

Tricholemmoma, a benign follicular neoplasm with outer root sheath differentiation, typically comprises clear or pale cells, and when multiple is pathognomic of Cowden's syndrome. The tumor is probably underrecognized and in basaloid examples can be difficult to distinguish from basal cell carcinoma (BCC). We studied 55 tricholemmomas (including 15 basaloid cases) and compared immunohistochemical profile with nodular BCC from our archives. Basaloid and non-basaloid tricholemmomas had similar staining characteristics. BerEP4 was focally positive (range 10%-20%) in only 3/39 (7.7%) tricholemmomas compared with widespread positivity in BCC (90.8%, 139 of 151 cases with ≥50% tumor area stained). CD34 was expressed, usually focally (median 20%, range 10%-90%), in 52/53 (98.1%) tricholemmomas and was negative in all 21 BCCs stained. EMA staining lacked sensitivity or specificity in differentiating tricholemmoma from BCC. Five or more Merkel cells were found in 7/17 (40.1%) tricholemmomas and 1/23 (4.3%) nodular BCCs studied. In summary, immunohistochemistry is helpful in distinction between tricholemmoma, including difficult basaloid examples (BerEP4 negative or focal, CD34 positive) compared with BCC (BerEP4 widespread in most cases, CD34 negative). The presence of 5 or more Merkel cells is a relatively specific but not a particularly sensitive discriminator.

A Limited Immunohistochemical Panel to Distinguish Basal Cell Carcinoma of Cutaneous Origin From Basaloid Squamous Cell Carcinoma of the Head and Neck

Head and neck carcinomas with basaloid features can be diagnostically challenging. A common diagnostic issue is the distinction between a basaloid squamous cell carcinoma (bSCC) and a basal cell carcinoma (BCC) of cutaneous origin. This is particularly true in small biopsy specimens where classic architectural and histologic features may be difficult to appreciate. A specific diagnosis is essential because of significant differences in clinical outcome and therapeutic management. Ten resection cases of bSCC and BCC of the head and neck were selected based on primary location and the classic morphologic features that characterize these 2 entities. The following immunohistochemical markers were evaluated: epithelial membrane antigen (EMA), Ber-EP4, CD44, Bcl2, androgen receptor, SOX2, and p16. The strongest statistically significant differences in staining patterns were for EMA, p16, and SOX2. EMA was positive in all bSCCs and negative in all BCCs. SOX2 was positive in all bSCCs and in only 3 out of 10 BCCs. Staining was weak and peripheral in the SOX2-positive BCCs. p16 was positive in 8 out of 10 bSCCs and negative in all BCCs. We conclude that bSCC and BCC of the head and neck can be readily distinguished by a limited panel consisting primarily of EMA, and supported by SOX2 and p16.

Histologic Mimics of Basal Cell Carcinoma

CONTEXT

- Basal cell carcinoma (BCC) is the most common human malignant neoplasm and is a frequently encountered diagnosis in dermatopathology. Although BCC may be locally destructive, it rarely metastasizes. Many diagnostic entities display morphologic and immunophenotypic overlap with BCC, including nonneoplastic processes, such as follicular induction over dermatofibroma; benign follicular tumors, such as trichoblastoma, trichoepithelioma, or basaloid follicular hamartoma; and malignant tumors, such as sebaceous carcinoma or Merkel cell carcinoma. Thus, misdiagnosis has significant potential to result in overtreatment or undertreatment.

OBJECTIVE

- To review key features distinguishing BCC from histologic mimics, including current evidence regarding immunohistochemical markers useful for that distinction.

DATA SOURCES

- Review of pertinent literature on BCC immunohistochemistry and differential diagnosis.

CONCLUSIONS

- In most cases, BCC can be reliably diagnosed by histopathologic features. Immunohistochemistry may provide useful ancillary data in certain cases. Awareness of potential mimics is critical to avoid misdiagnosis and resulting inappropriate management.

Update on Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a rare, aggressive cutaneous neuroendocrine malignancy. Merkel cell polyomavirus, a tumorigenic DNA virus, is present in most MCC tumors, with implications for tumor biology, diagnosis, and management. Merkel cell polyomavirus-negative tumors have a high burden of UV-signature mutations, similar to melanoma. The histopathologic diagnosis of MCC requires immunohistochemistry to exclude morphologically similar entities. Therapies for advanced disease are currently lacking. Here, the features of MCC are reviewed, including recent molecular discoveries with implications for improved therapy for advanced disease.

Topics in histopathology of sweat gland and sebaceous neoplasms

This article reviews several topics regarding sweat gland and sebaceous neoplasms. First, the clinicopathological characteristics of poroid neoplasms are summarized. It was recently reported that one-fourth of poroid neoplasms are composite tumors and one-fourth are apocrine type lesions. Recent progress in the immunohistochemical diagnosis of sweat gland neoplasms is also reviewed. CD117 can help to distinguish sweat gland or sebaceous tumors from other non-Merkel cell epithelial tumors of the skin. For immunohistochemical differential diagnosis between sweat gland carcinoma (SGC) other than primary cutanesous apocrine carcinoma and skin metastasis of breast carcinoma (SMBC), a panel of antibodies may be useful, including p63 (SGC⁺ , SMBC^- ), CK5/6 (SGC⁺ , SMBC^- ), podoplanin (SGC⁺ , SMBC^- ) and mammaglobin (SGC^- , SMBC⁺ ). Comparison of antibodies used for immunohistochemical diagnosis of sebaceous carcinoma (SC) suggests that adipophilin has the highest sensitivity and specificity. Some authors have found that immunostaining for survivin, androgen receptor and ZEB2/SIP1 has prognostic value for ocular SC, but not extraocular SC. In situ SC is rare, especially extraocular SC, but there have been several recent reports that actinic keratosis and Bowen's disease are the source of invasive SC. Finally, based on recent reports, classification of sebaceous neoplasms into three categories is proposed, which are sebaceoma (a benign neoplasm with well-defined architecture and no atypia), borderline sebaceous neoplasm (low-grade SC; an intermediate tumor with well-defined architecture and nuclear atypia) and SC (a malignant tumor with invasive growth and evident nuclear atypia).

Comparison of EMA,CEA, CD10 and Bcl-2 Biomarkers by Immunohistochemistry in Squamous Cell Carcinoma and Basal Cell Carcinoma of the Skin

BACKGROUND

Basal and squamous cell carcinoma (BCC and SCC) are the most common skin cancers worldwide and distinction between the two may sometimes be very difficult in routine histopathology. The present study was aimed to evaluate a reliable diagnostic method for these cancers based on immunohistochemistry (IHC).

MATERIALS AND METHODS

IHC was used with antibodies to Bcl-2, CD10, CEA, and EMA biomarkers, which despite non-specificity are easily available for detection of various types of tumors in pathology sections and can be used as a panel for differentiation. In this descriptive and analytic study, paraffin- embedded blocks of 29 SCC patients and 29 BCC patients were collected and sectioned for IHC staining. The results were analyzed by the STATA (version 8) statistical package using the Chi-square test.

RESULTS

BCC patients were 100%, 75.8%, 0% and 0% positive for Bcl-2, CD10, CEA and EMA markers, respectively, and for SCC patients were 3.5%, 0%, 34.5% and 82.7% positive, respectively. Using simultaneously Bcl-2 and CD10 as positive markers, detection of BCC with 88% accuracy and 100% specificity was possible, while application of CEA and EMA positivity could detect SCC with 67% accuracy and 100% specificity.

CONCLUSIONS

SCC and BCC have different immunostaining profiles; therefore, Bcl-2, CD10, CEA and EMA markers can be helpful to distinguish between them.

Sinonasal small round blue cell tumors: An approach to diagnosis

The differential diagnosis for small round cell tumors in the sinonasal tract is diverse and as the body of literature documenting not only uncommon presentations but also availability of ancillary studies grows, so does the need for a reminder to take a conservative and thorough approach before rendering a diagnosis. Small tissue samples are particularly problematic, with limitations that include volume of tumor cells available for studies, lack of architectural context and a non-specific gross description. Incorporation of patient history and presentation, radiologic findings, clinical impression and concurrent studies often guide the course of studies performed by the pathologist. If these are non-specific, the pathologist may need to perform ancillary studies, including a broad panel of immunohistochemical stains and molecular studies. If tissue is limited, a precise classification may not be achievable. Although the expectation to render a definitive diagnosis is high, the pathologist should never feel compelled to go further with a diagnosis than the tissue itself supports.

Markers for Sebaceoma Show a Spectrum of Cell Cycle Regulators, Tumor Suppressor Genes, and Oncogenes

BACKGROUND

Sebaceoma is a tumor for which the causative oncogenes are not well-understood. Sebaceomas demonstrate some histopathologic features similar to basal cell carcinoma (BCC), such as palisading borders and basaloid cells with additional features, including foamy cytoplasm and indented nuclei.

AIMS

We examine multiple cell-cycle, oncogene, and tumor suppressor gene markers in sebaceomas, to try to find some suitable biological markers for this tumor, and compare with other published studies.

MATERIALS AND METHODS

We investigated a panel of immunohistochemical (IHC) stains that are important for cellular signaling, including a cell cycle regulator, tumor suppressor gene, oncogene, hormone receptor, and genomic stability markers in our cohort of sebaceomas. We collected 30 sebaceomas from three separate USA dermatopathology laboratories. The following IHC panel: Epithelial membrane antigen (EMA)/CD227, cytokeratin AE1/AE3, cyclin D1, human breast cancer 1 protein (BRCA-1), C-erb-2, Bcl-2, human androgen receptor (AR), cyclin-dependent kinase inhibitor 1B (p27(kip1)), p53, topoisomerase II alpha, proliferating cell nuclear antigen, and Ki-67 were tested in our cases.

RESULTS

EMA/CD227 was positive in the well-differentiated sebaceomas (13/30). Cyclin-dependent kinase inhibitor 1B was positive in tumors with intermediate differentiation (22/30). The less well-differentiated tumors failed to stain with EMA and AR. Most of the tumors with well-differentiated palisaded areas demonstrated positive staining for topoisomerase II alpha, p27(kip1), and p53, with positive staining in tumoral basaloid areas (22/30). Numerous tumors were focally positive with multiple markers, indicating a significant degree of variability in the complete group.

CONCLUSIONS

Oncogenes, tumor suppressor genes, cell cycle regulators, and hormone receptors are variably expressed in sebaceomas. Our results suggest that in these tumors, selected marker staining seems to correlate with tumor differentiation; that is, well-differentiated tumors as a group stained with EMA and AR, and palisaded areas demonstrated consistent p53, topoisomerase II alpha and p27(kip1) staining. In contrast, less well-differentiated areas stained with a different spectrum of markers.

Multifocal metastasizing extra-ocular facial sebaceous carcinoma as diagnostic challenge: case report and systematic review

PURPOSE

Sebaceous carcinoma (SC) is a rare adnexal tumor. Extra-ocular, facial SC is very uncommon and local metastases are an extreme rare finding. A respective case is presented and discussed together with the current literature.

CASE AND REVIEW

A tumor of the left ear of an 87-old male was primary excised together with multiple suspicious lesions of the head and neck. Most specimens were histopathologically rated as squamous cell carcinomas (SCC). Despite the in-sano resection, additional new suspicious retro-auricular and temporal lesions were detected. Successive resections were diagnosed as basal cell carcinomas (BCC) and, because of a non-in-sano resection in a third approach, as SC. After reappraisal and immunhistochemical staining [epithelial membrane antigen (EMA), CK 5-6 and CD 15], most of the former specimens turned out to be SC as well. A literature search showed 3 reported cases of extra-ocular head and neck SC with cutaneous local metastases. In another review, in a total of 168 cases, SC was diagnosed after wrong initial histological diagnosis (SCC n = 56, BCC n = 44; other entity or precursors of carcinomas n = 68).

CONCLUSION

Due to inconsistent histologic patterns, histopathological misdiagnosis of the uncommon facial SC and its metastases may complicate further therapy, prolong treatment and may lead to a worse prognosis of this neoplasm. A close interdisciplinary collaboration of clinician, surgeon and pathologist is of most relevance for the right diagnosis.

Diagnosis and treatment of clear cell hidradenocarcinoma of the scalp

Clear cell hidradenocarcinoma (CCH) is an exceedingly rare and highly malignant tumor of the eccrine sweat glands. Its treatment is extremely difficult due to the characteristically aggressive clinical course including repeated local recurrence and uncontrollable distal metastasis coming along with a very poor prognosis. Most published case studies recommend a wide surgical excision followed by adjuvant conservative therapy, which is generally considered to be the standard treatment. Two cases of nodular CCH of the scalp either presenting as a singular primary lesion or at an already metastatic stage were analyzed retrospectively. Wide local excision of the tumor couldn't prevent the primary carcinoma from recurring and metastasizing. Both cases received various therapies but the results were unsatisfactory. Although most authors have recommended that early wide surgical excision of the tumor is a feasible therapeutic measurement, our results raise doubts on the efficacy of this treatment strategy. As alternative approaches (i.e. chemotherapy, radiotherapy) are similarly controversial, further studies and a wide exchange of clinical experiences are crucial.

Role of immunohistochemistry in diagnosing tumors of cutaneous appendages

In recent years, there has been significant progress in immunohistochemistry as an ancillary tool in diagnostic dermatopathology. In most instances, the histologic diagnosis can be rendered with the routine histologic sections; however, immunohistochemistry can help to narrow the differential in diagnosing neoplasms of cutaneous appendages in some settings including adnexal versus epidermal origin, benign versus malignant adnexal neoplasms, and primary adnexal carcinoma versus cutaneous metastases as outlined in this review.

Sebaceous carcinoma: an immunohistochemical reappraisal

The rates of distant metastases and tumor death in sebaceous carcinoma (SC) have been reported to be higher than those of other cutaneous carcinomas, such as squamous cell carcinoma (SCC) and basal cell carcinoma (BCC), regardless of whether they occur in ocular or extraocular regions. Therefore, strict differentiation of SC from SCC and BCC is required. In this article, we report immunohistochemical findings of SC and compare these data to those of SCC, BCC, and sebaceoma. An immunohistochemical study was performed using 7 antibodies [anti-carcinoembryonic antigen (CEA), anti-epithelial membrane antigen (EMA), anti-CA15-3, anti-CA19-9, anti-androgen receptor (AR), anti-epithelial antigen (Ber-EP4), and anti-adipophilin (ADP)] on 35 cases of SC (16 cases in ocular and 19 cases in extraocular regions) and 10 cases of each SCC (5 cases in ocular and 5 cases in extraocular regions), BCC (5 cases in ocular and 5 cases in extraocular regions), and sebaceoma (no cases arose on the eyelids). In summary, the typical immunophenotypes of SC were EMA+, CA15-3+, AR+, Ber-EP4-, and ADP+; those of sebaceoma were CEA-, EMA+, Ber-EP4-, and ADP+; those of SCC were CEA-, EMA+, CA19-9-, AR-, Ber-EP4-, and ADP-; and those of BCC were CEA-, EMA-, CA15-3-, Ber-EP4+, and ADP-. Other antibody tests for each neoplasm were positive in about half of the cases. The detection of AR and ADP was useful for differentiating SC from SCC, whereas the determination of EMA, CA15-3, Ber-EP4, and ADP was valuable in differentiating SC from BCC.

Aberrant upregulation of MUC4 mucin expression in cutaneous condyloma acuminatum and squamous cell carcinoma suggests a potential role in the diagnosis and therapy of skin diseases

AIM

Mucins comprise a family of high-molecular-weight glycoproteins. MUC4, a large transmembrane mucin, has recently emerged as a novel marker for diagnosis, prognosis and therapy in several malignancies. However, its role in skin pathologies remains unknown. The aim of this study was to analyse the expression of MUC4 in cutaneous pathologies by immunohistochemistry for potential diagnostic, prognostic and therapeutic applications.

METHODS

A total of 330 tissue spots representing the normal skin, and benign and malignant cutaneous diseases, were analysed after staining with the monoclonal antibody to human MUC4 (clone 8G7).

RESULTS

While the normal epidermis showed a negative to weak-positive expression of MUC4, its expression was significantly upregulated in squamous cell carcinomas (SCCs) where the intensity of staining correlated negatively with tumour grade and positively with age. A moderately strong MUC4 expression was also noted in 2/20 cancer adjacent normal skin and 2/21 chronically inflamed skin tissues, while 10/19 cases of vulval condyloma acuminate, 3/12 of vulval hyperplasia and 2 cases of verruca vulgaris also showed strong MUC4 positivity. Malignant melanoma, basal cell carcinoma and cutaneous cysts were negative.

CONCLUSION

The results indicate that MUC4 expression is aberrantly upregulated in cutaneous SCCs, vulval condylomas and verruca vulgaris. Further, it appears that MUC4 expression in the skin may be modulated by chronic inflammation and the presence of an adjacent cutaneous malignancy in certain cases. These observations suggest a novel role for MUC4 mucin in the pathogenesis of cutaneous SCC and a possible application as a diagnostic and/or prognostic marker in cutaneous pathologies.

Role of mucins in the skin during benign and malignant conditions

Skin-related diseases comprise a major health challenge to the practicing physician, and constitute a significant psychological, social and financial burden to the society. Further, skin cancer, especially non-melanoma skin cancer is currently the leading type of malignancy in the Western world. Given the huge burden of skin diseases, there is growing emphasis on understanding their pathophysiology, and towards their early detection. Mucins are high-molecular weight O- and N-linked glycoproteins that have emerged in recent years as important molecules in maintaining health and in promoting or protecting against inflammation and cancer. They have also begun to emerge as highly specific diagnostic and prognostic markers and novel therapeutic targets in several malignant disorders. However, their role in cutaneous pathologies has remained largely obscured. The present review provides the expression patterns and proposed role of mucins in the healthy skin and various benign and malignant skin diseases. The review has immense clinical significance as the availability of highly specific reagents including monoclonal antibodies against mucins makes them extremely attractive targets for specific diagnosis and/or immunotherapy of benign and malignant cutaneous diseases.

The use of immunohistochemistry in the diagnosis of metastatic clear cell renal cell carcinoma: a review of PAX-8, PAX-2, hKIM-1, RCCma, and CD10

The diagnosis of metastatic clear cell renal cell carcinoma may be difficult in some cases, particularly in the small image-guided biopsies that are becoming more common. As targeted therapies for renal cell carcinoma are now standard treatment, the recognition and diagnosis of renal cell carcinoma has become even more critical. Many adjunctive immunohistochemical markers of renal epithelial lineage such as CD10 and RCCma have been proposed as aids in the diagnosis of metastatic renal cell carcinoma, but low specificities often limit their utility. More recently described markers (PAX-2, PAX-8, human kidney injury molecule-1, hepatocyte nuclear factor-1-β, and carbonic anhydrase-IX) offer the potential for greater sensitivity and specificity in this diagnostic setting; however, knowledge of their expected staining in other neoplasms and tissues is critical for appropriate use. In this review, we discuss the most widely used immunohistochemical markers of renal lineage with an emphasis on their sensitivity and specificity for metastatic clear cell renal cell carcinoma. Subsequently, we present a variety of organ-specific differential diagnostic scenarios in which metastatic clear cell renal cell carcinoma might be considered and we propose immunopanels for use in each situation.

Sebaceous cell carcinoma of the ocular adnexa: clinical presentations, histopathology, and outcomes

PURPOSE

To investigate the clinical features, time to diagnosis, histopathology, treatment, and mortality rates of patients with sebaceous cell carcinoma.

METHODS

This was a retrospective, consecutive series of patients with sebaceous cell carcinoma at a tertiary referral medical center. Between January 1984 and January 2006, 31 patients with sebaceous cell carcinoma were evaluated at the Department of Ophthalmology and Visual Sciences, University of Iowa Hospitals and Clinics. The main outcome measures were clinical presentations, treatments, reconstructive procedures, and outcomes.

RESULTS

Thirty-one patients were diagnosed with sebaceous cell carcinoma of the ocular adnexa on histopathology. Twenty (65%) of the patients were women and 11 were men. The upper eyelid was involved in 18 patients, lower eyelid in 10, both upper and lower eyelids in 1, and caruncle in 2. Twenty-three patients had in situ disease, pagetoid disease, or both. Eight patients reported symptoms for <6 months and 22 had symptoms for < or = 12 months before the diagnosis of sebaceous cell carcinoma was made. Local surgical excision of the tumor as initial treatment was performed in 25 patients. Exenteration was the initial surgery performed in 4 patients. Two patients died from metastatic sebaceous cell carcinoma.

CONCLUSIONS

Sebaceous cell carcinoma has varied presentations and is commonly misdiagnosed. Tumor-related deaths occurred in only 2 patients (6.7%), which is lower than previous reports and may be related to earlier detection or improved surgical excision techniques.

Diagnosis and management of sebaceous carcinoma: an Australian experience

BACKGROUND

Cutaneous sebaceous carcinoma (SC) is a rare malignancy derived from adnexal epithelium of sebaceous glands. Periorbital SC is approximately three times more common than extraorbital SC. To date, there are few data from an Australian source to document the prevalence or clinical outcome of this tumour.

METHODS

A retrospective review was undertaken of the cases from the Institute of Clinical Pathology and Medical Research using their histopathology database for patients with a diagnosis of SC. Patients were identified over a period of 34 years from 1971-2005 and their management and follow up are reported.

RESULTS

There were 25 patients in all. Seventeen were men and eight were women. Of the 25 cases, 12 were extraorbital and 13 were periorbital. Three metastases and one tumour showed extensive local invasion. There were nine cases of incomplete excisions and 13 patients were reoperated on for either incomplete excisions, to obtain a wider margin or for local recurrences. Adjuvant radiotherapy was used on five patients, three of whom had lymph node deposits.

CONCLUSION

Sebaceous carcinoma is a rare tumour. Extraorbital SC is an aggressive and invasive malignancy. Excision margins may need to be wider than previously thought. Exposure to ultraviolet radiation (sunlight) may play a role in the aetiology. Wide excision and selective use of radiotherapy remain the treatment of choice.

Ectopic hamartomatous thymoma: a case demonstrating skin adnexal differentiation with positivity for epithelial membrane antigen, androgen receptors, and BRST-2 by immunohistochemistry

Ectopic hamartomatous thymoma is a rare tumor of the lower neck occurring in adult men, which follows a benign course. They are triphasic with epithelial, adipocytic, and spindled elements in variable amounts. The origin of this tumor has been debated, but it is now believed to arise from remnants of the cervical sinus of His from early development. We describe a case of ectopic hamartomatous thymoma with typical features, as well as multifocal areas of skin adnexal differentiation. These included sebaceous, eccrine, and apocrine elements. We highlighted these by using immunohistochemistry to epithelial membrane antigen, BRST-2, and androgen receptors (AR). Epithelial membrane antigen stained sebaceous cells and the luminal borders of eccrine and apocrine ducts. BRST-2 and AR stained apocrine elements in a cytoplasmic and a nuclear pattern, respectively. The spindled component also expressed nuclear AR. AR positivity has not been described previously and may explain the occurrence primarily in men in postpubertal life.

Immunohistochemical differentiation of extra-ocular sebaceous carcinoma from other skin cancers

We performed an immunohistochemical study using routinely processed formalin-fixed and paraffin-embedded tissue specimens from 26 cases of extra-ocular sebaceous carcinoma (EOSC) and eight easily available antibodies. They were polyclonal anti-carcinoembryonic antigen (CEA) antibody, monoclonal anti-CEA antibody, anti-breast carcinoma associated antigen-225 antibody (CU18), anti-CA15.3 antibody (CA15.3), anti-CD15 antibody (CD15), anti-breast carcinoma associated antigen antibody (B6.2), anti-gross cystic disease fluid antigen-15 antibody (GCDFP15) and anti-Thomsen-Friedenreich antigen antibody (TFA). Squamous cell carcinoma, porocarcinoma, syringomatous carcinoma, malignant clear cell hidradenoma, apocrine adenocarcinoma, and extramammary Paget's disease with underlying adenocarcinoma were used as controls. EOSC was positive for CU18 and CA15.3 in most cases, and for CD15 in a few cases. Squamous cell carcinoma of the skin was positive for CA15.3 in only one case. Porocarcinoma, syringomatous carcinoma and malignant clear cell hidradenoma were positive for CEA, CU18, CA15.3, and B6.2 in most cases. Apocrine adenocarcinoma and extramammary Paget's disease with underlying adenocarcinoma were positive for CEA, CU18, CD15, GCDFP15, CA15.3, and B6.2 in most cases. TFA was positive not only in EOSC but also in other skin cancers. Immunohistochemical examinations using these seven of eight antibodies except for TFA and routinely processed formalin-fixed and paraffin-embedded tissue specimens are beneficial in differentiating EOSC from other skin cancers.

Expression and glycosylation of MUC1 in epidermolysis bullosa-associated and sporadic cutaneous squamous cell carcinomas

BACKGROUND

Cutaneous squamous cell carcinoma (SCC) is particularly problematic in certain patient groups, including patients with dystrophic or junctional epidermolysis bullosa (DEB/JEB). Theoretically, vaccination against a cell surface antigen which is expressed on this type of tumour could prevent SCC development, as well as treat primary and metastatic disease in this patient group. Preliminary studies have suggested that MUC1, a transmembrane glycoprotein, is overexpressed in sporadic cutaneous SCCs, and MUC1 has been used with some success as a target antigen for vaccine development in breast cancer, where it is expressed on > 50% of neoplastic cells in approximately 50-80% of tumours. Furthermore, aberrant glycosylation of MUC1 has been detected in this and other cancer types; however, the glycosylation status of MUC1 in cutaneous SCC is not known.

OBJECTIVES

To investigate the expression and glycosylation status of MUC1 in SCCs arising in patients with DEB and JEB, and for comparison in sporadic SCCs and sporadic Bowen's disease.

METHODS

Immunohistochemical analysis of MUC1 in 30 SCCs from subjects with DEB/JEB, 55 sporadic SCCs and 30 sporadic lesions of Bowen's disease was carried out using four separate monoclonal antibodies which recognize different isoforms of MUC1.

RESULTS

Expression of MUC1 was detected in 100% of SCCs arising in patients with DEB and JEB; > 50% of neoplastic cells stained positive for MUC1 in 57% of DEB/JEB SCCs, with over 95% of tumour cells immunopositive in 33% of cases. MUC1 expression was also observed in 95% of sporadic SCCs and 97% of Bowen's disease, with 36% of sporadic SCCs immunopositive for MUC1 in > 50% of tumour cells. Investigation of the glycosylation status showed that MUC1 was predominantly hyperglycosylated in the DEB/JEB and sporadic tumours.

CONCLUSIONS

The results demonstrate that a significant proportion of DEB/JEB and sporadic SCCs express MUC1 in > 50% of tumour cells. Therefore, MUC1 may be a suitable candidate antigen against which to develop a tumour vaccine for these patient groups.

Use of Ber-EP4 protein in recurrent metastatic basal cell carcinoma: a case report and review of the literature

The occurrence of metastatic basal cell carcinoma (MBCC) is extremely low, ranging from 0.0028 to 0.5%. We present a rare case report of MBCC in a 57-year-old Caucasian male with a known history of numerous nonmelanoma cutaneous neoplasms. The patient presented with a large ulcerated right axillary mass that recurred 2 months after an initial BCC was resected from the same site. An excisional biopsy of the recurrent mass and regional lymph nodes showed atypical basaloid cells with hyperchromatic nuclei, stromal retraction and rare squamous features in the soft tissue and lymph node. The tumor cells were bcl-2 negative and positive for Ber-EP4. The negative expression of bcl-2 correlates with the aggressive nature of this tumor and Ber-EP4 confirmed the diagnosis of BCC.

Dimorphic immunohistochemical staining in ocular sebaceous neoplasms: a useful diagnostic aid

PURPOSE

We studied whether patterns of immunostaining in formalin-fixed, paraffin-embedded tissue could help to distinguish between sebaceous neoplasms of the eyelid and other eyelid neoplasms.

METHODS

We applied antibodies to human milk fat globule-1 (HMFG1), cytokeratins (PKK1 and MNF116), epithelial membrane antigen (EMA) and carcino-embryonic antigen (CEA) to normal eyelid tissue and to a range of sebaceous lesions of the eyelid; these included sebaceous hyperplasia, sebaceous adenoma and sebaceous epithelioma, in addition to well to poorly differentiated sebaceous carcinoma.

RESULTS

The central and peripheral cellular components of normal sebaceous glands and neoplastic sebaceous lesions showed a distinctive dimorphic staining pattern with the antibody panel used. The central foamy 'sebaceous' cells expressed HMFG1 and EMA, but not PKK1 or MNF116, whereas the smaller, peripheral basal and ductal cells expressed PKK1 or MNF116 but not HMFG1 or EMA. CEA expression in sebaceous cells was unhelpful diagnostically.

CONCLUSION

Normal sebaceous glands and all sebaceous neoplasms show a dimorphic cell population that can be identified using a small panel of antibodies on formalin-fixed, paraffin-embedded tissue. This distinctive staining pattern can be assessed retrospectively, even in small biopsies, and largely removes the need for fat stains on frozen sections to differentiate sebaceous lesions from other ocular neoplasms. The results also support the suggestion that ocular sebaceous neoplasms arise from a common stem cell, rather than from either sebaceous or basal/ductal cells.

Immunohistochemistry in diagnostic dermatopathology

This article briefly reviews many immunohistochemical stains that have been in use for years, emphasizing their diagnostic use and potential pitfalls. Several newer immunostains are described in a more comprehensive fashion, including brief summaries from recently published studies.

An immunohistochemical study of the apocrine type of cutaneous mixed tumors with special reference to their follicular and sebaceous differentiation

An immunohistochemical analysis of 8 cases of the apocrine type of cutaneous mixed tumor is reported. Histologically, 7 cases of the tumor were suggested to have follicular and/or sebaceous differentiation. Carcinoembryonic antigen (CEA), epithelial membrane antigen and gross cystic disease fluid protein-15 were present in the inner surface and/or in the luminal cell bodies of the tubular structures. CEA and non-specific cross-reacting antigen were also detected in the keratinous cysts. Positive reactions for S-100 protein and vimentin were observed in the solid nests, the outer layer of the tubular structures and some stromal cells. However, smooth muscle actin was only focally expressed in the outer cells of the tubular nests in one case. Involucrin was positive in the inner layers of the keratinous cysts. Various staining patterns were observed in the keratin immunohistochemistry. The solid nests showed heterogeneous expressions of CK1/5/10/14, CK7, CK10/11, CK14, CK8/18 and CK19. The inner cells of the tubular structures were constantly positive for CK7, CK8/18 and CK19, and heterogeneously for CK1/5/10/14, CK10/11 and CK14. The outer cells were heterogeneously positive for CK1/5/10/14 and CK14. The keratinous cysts showed positive reactions for CK1/5/10/14 throughout the whole cell layers, and for CK14 in the basal layer. The inner layers in some keratinous cysts expressed CK6, CK10/11 and CK17, but only CK10 in others. CK13 was positively stained in the transitional portion between the matricial structure and the column of shadow cells in the cyst wall in only one case. When compared with the immunohistochemistry of the normal skin, the apocrine type of cutaneous mixed tumor can show various immunophenotypical patterns similar to those of entire structures of hair follicles, sebaceous glands and all components of apocrine glands, that is to say, the folliculosebaceous-apocrine unit.

Nonneoplastic disorders of the eccrine glands

Eccrine glands are uniquely susceptible to a variety of pathologic processes. Alteration in the rate of sweat secretion manifests as hypohidrosis and hyperhidrosis. Obstruction of the eccrine duct leads to miliaria. The excretion of drugs into eccrine sweat may be a contributory factor in neutrophilic eccrine hidradenitis (NEH), syringosquamous metaplasia (SSM), coma bulla, and erythema multiforme (EM). Alterations in the electrolyte composition of eccrine sweat can be observed in several systemic diseases, most notably cystic fibrosis. This article summarizes current knowledge of eccrine gland pathophysiology.

Human collagenase-3 is expressed in malignant squamous epithelium of the skin

Co-expression of several members of the matrix metalloproteinase (MMP) family is a characteristic of human carcinomas. To investigate the role of the recently cloned collagenase-3 (MMP-13) in epidermal tumors, we studied samples representing malignant (basal and squamous cell carcinoma, Paget's disease), pre-malignant (Bowen's disease, solar keratosis), and benign (keratoacanthoma, seborrheic keratosis, linear epidermal nevus) tumors. Basal cell carcinomas expressed collagenase-3 mRNA in focal areas of keratinized cells, the squamous differentiation of which was confirmed by positive immunostaining for involucrin. Apoptosis was observed in central parts of these foci. In squamous cell carcinomas, collagenase-3 expression was detected at the epithelial tumor front and less frequently in the surrounding stromal cells. Collagenase-3 mRNA co-localized with immunostaining for laminin-5, an adhesion molecule suggested to participate in the migration of tumor cells. The pre-malignant and benign tumors were mostly negative for collagenase-3. Stromelysin-1, a potential activator of latent collagenases, was frequently expressed by stromal cells surrounding the malignant tumors, and the two MMPs occasionally co-localized in keratotic foci. Our results demonstrate that in basal cell carcinomas, expression of collagenase-3 is associated with terminal differentiation of epithelial cells. Furthermore, the gene is activated during skin carcinogenesis, and we suggest a role for collagenase-3 in degradation of the extracellular matrix associated with malignant epithelial growth.

Ultrastructural localization of carcinoembryonic antigen (CEA) glycoproteins and epithelial membrane antigen (EMA) in normal and neoplastic sweat glands

Glycoproteins of the carcinoembryonic antigen family (CEA) and epithelial membrane antigen (EMA) are established markers for glandular and mucosal tissues. However, their precise ultrastructural distribution in sweat glands has not been determined as yet. Therefore, normal human skin, 19 cases of various sweat gland neoplasms, Paget's disease, and cutaneous metastases of visceral carcinomas were stained with well-defined antibodies using a postembedding immunogold technique. In some cases, a new method of re-embedding paraffin material for immunoelectron microscopy was applied. In normal sweat glands, immunoreactivity of the endoplasmic reticulum and vesicles indicated biosynthesis and processing of CEA and EMA. Along the luminal surfaces both CEA and EMA represented an integral part of microvilli. However, a differential expression of CEA and EMA was demonstrated in apocrine epithelia, mucous cells of eccrine glands, and sweat ducts. In fetal glands, CEA was associated with formation of secretory and ductal lumina. The overall cellular distribution of CEA and EMA was highly preserved in benign sweat gland neoplasms whereas malignant neoplasms were characterized by loss of protein targeting and cellular polarity. In conclusion, these immunoelectron microscopical findings suggest a role of CEA and EMA for cell differentiation and secretory mechanisms of sweat gland epithelia.

Perianal basal cell carcinoma: a comparative histologic, immunohistochemical, and flow cytometric study with basaloid carcinoma of the anus

Perianal basal cell carcinoma is a very rare tumor accounting for only 0.2% of the anorectal tumors. It must be distinguished from basaloid carcinoma of the anus, which resembles it histologically but shows a much more aggressive behavior, metastasizes early, and often proves fatal, thus requiring different therapy. Differential diagnosis of both entities by light microscopy may be difficult. Five cases of perianal basal cell carcinoma and five cases of basaloid carcinoma were studied by means of immunohistochemistry and flow cytometry. Some immunohistochemical markers, such as epithelial membrane antigen, carcinoembrionic antigen, and keratins, as well as the lectin Ulex europaeus agglutinin I stained basaloid carcinoma and were negative for basal cell carcinoma. In contrast, the monoclonal antibody Ber-EP4 seems to be a good marker for perianal basal cell carcinoma and useful in differentiating it from basaloid carcinoma of the anus. Basaloid carcinomas are associated with a significantly higher S-phase fraction than are perianal basal cell carcinomas (p < 0.01).

Expression of a glycoprotein of the carcinoembryonic antigen family in normal and neoplastic sebaceous glands. Limited role of carcinoembryonic antigen as a sweat gland marker

BACKGROUND

Carcinoembryonic antigen (CEA) is a well-known marker for sweat gland differentiation in adnexal neoplasms.

OBJECTIVE

The aim of this study was to examine the expression of glycoproteins of the CEA family, that is, CEA-180, nonspecific cross-reacting antigens (NCAs), and biliary glycoprotein (BGP), in sebaceous glands and in neoplasms with sebaceous differentiation.

METHODS

Normal adult and fetal skin, hyperplasias, hamartomas, and neoplasms with sebaceous or follicular differentiation were stained immunohistochemically with a panel of polyclonal and monoclonal antibodies highly specific for CEA-180, NCAs, and BGP. Double immunostaining was performed to correlate the CEA expression with that of epithelial membrane antigen (EMA), a glycoprotein consistently found in differentiating sebocytes.

RESULTS

Whereas sweat glands coexpressed CEA, NCAs, BGP, and EMA, sebaceous glands were exclusively labeled with the antibodies recognizing BGP or EMA. Staining of the sebaceous glands was restricted to mature sebocytes, sparing immature cells. At the ultrastructural level immunoreactivity for BGP and EMA was demonstrable in the golgi area, in small vesicles, and along the cell membranes. During fetal development BGP was not found until the sebaceous glands matured. The expression of BGP and EMA was highly conserved in reactive, hamartomatous, and neoplastic proliferations of adnexal structures with sebaceous differentiation.

CONCLUSION

The expression of BGP, a CEA glycoprotein, in differentiating sebocytes accounts for the reactivity of many anti-CEA antibodies with sebaceous glands and thus disqualifies the CEA family as a monospecific marker for sweat gland differentiation.

Immunohistochemistry in diagnostic dermatopathology

Immunopathology continues to be important in diagnostic dermatopathology. Immunopathology is an invaluable tool for assessing the tissue of origin or direction of differentiation of cells. In some cases this can result in a more precise diagnosis. This article reviews the role of immunopathology in determining the biologic behavior of hematolymphoid infiltrates. It explores the methodology of immunoperoxidase, discusses the most commonly used antibody reagents, and presents a series of diagnostic dilemmas in which immunopathology can be useful. In each case a strategy is established that maximizes the likelihood of making a definitive diagnosis.

Neoplasms with sweat gland differentiation express various glycoproteins of the carcinoembryonic antigen (CEA) family

Carcinoembryonic antigen (CEA) is a well-established marker for sweat gland differentiation in adnexal neoplasms. In contrast to previous assumptions, CEA does not represent a single oncofetal antigen but comprises a family of homologous glycoproteins, i.e. the classical CEA-180, biliary glycoprotein (BGP), and non-specific crossreacting antigens (NCA). The aim of the study was to evaluate the distribution of the respective glycoproteins of the CEA family in sweat gland neoplasms, as compared to normal sweat glands. A panel of mono-specific antibodies was applied to a total of 83 samples of hyperplastic and cystic alterations of sweat glands, sweat gland neoplasms, and cutaneous metastases of different origin. Within a single group of neoplasms the immunohistochemical profile was rather consistent. Staining for both CEA-180 and NCA-90 indicated ductal differentiation of both eccrine and apocrine glands. Co-expression of CEA-180, NCA-90, and BGP was consistent with differentiation towards the secretory part of eccrine glands or the transitional portion of proximal ducts. Neoplasms with signs of apocrine secretion showed a preferential immunoreactivity for NCA-90 and BGP. In conclusion, a specification of the members of the CEA family may be of some value in the differential diagnosis of adnexal neoplasms, but not in the discrimination of sweat gland carcinoma from metastatic carcinoma.

Clear cell eccrine carcinomas of the skin. A clinicopathologic study of nine patients

BACKGROUND

Sweat gland carcinomas with clear cell features are extremely rare neoplasms, with few well documented cases reported in the literature.

METHODS

Data on nine patients with malignant eccrine adnexal neoplasms characterized by a prominent clear cell neoplastic component were studied. Immunohistochemical stains with a panel of antibodies against epithelial, stromal, and neural antigens were performed on five tumors and electron microscopic examination of one.

RESULTS

The tumors showed a spectrum of histologic features and growth patterns that ranged from well differentiated, low grade malignant neoplasms to poorly differentiated, highly aggressive, recurrent, and metastasizing tumors. All tumors contained a varied proportion of cells with abundant clear cytoplasm, similar to those seen in a group of benign eccrine adnexal neoplasms that have been variously designated as clear cell hidradenoma, nodular hidradenoma, clear cell myoepithelioma, and eccrine acrospiroma. Immunohistochemical stains on five tumors and ultrastructural examination in one were consistent with eccrine differentiation. Clinical follow-up of eight patients showed local recurrence in six, followed by metastases in three, despite local excision, radiation, and chemotherapy. Criteria for differentiating these tumors from their benign counterparts and from other types of malignant adnexal neoplasms and metastatic lesions are presented.

CONCLUSIONS

The findings indicate that clear cell eccrine carcinomas comprise a heterogeneous group of lesions that may range from locally recurring, low grade well differentiated tumors to highly aggressive, high grade tumors with a definite potential for uncontrollable local recurrence and metastasis. Wide surgical excision is recommended as the primary treatment for such neoplasms.

An immunohistochemical study of BCA-225 in various skin cancers

We performed an immunohistochemical study of BCA-225, which is a glycoprotein secreted by the T47D breast carcinoma cell line and recognized by monoclonal antibody BRST-1 (clone name: CU-18), in normal skin and various skin cancers. In normal skin, BCA-225 was positive only in the secretory portion of both eccrine and apocrine glands and in mature cells of the sebaceous gland. We observed 10 cases of squamous cell carcinoma of the skin, 10 cases of basal cell carcinoma without sebaceous differentiation, 3 cases of basal cell carcinoma with sebaceous differentiation, 6 cases of malignant trichilemmoma, 8 cases of eccrine porocarcinoma, 3 cases of ductal carcinoma, 1 case of malignant clear cell hidradenoma, 1 case of apocrine adenocarcinoma, 6 cases of extra-ocular sebaceous carcinoma, 5 cases of extramammary Paget's disease with underlying adenocarcinoma, and 11 cases of extramammary Paget's disease without underlying adenocarcinoma. Most of the cases of sweat gland carcinoma, basal cell carcinoma with sebaceous differentiation, sebaceous carcinoma, and extramammary Paget's disease were positive for BCA-225, while none of the cases of squamous cell carcinoma, basal cell carcinoma without sebaceous differentiation, or malignant trichilemmoma were positive. Based on these findings, we believe that BCA-225 is useful in distinguishing tumors with sweat gland and sebaceous differentiation and extramammary Paget's disease from tumors without such differentiation.

A histochemical and immunohistochemical study of extra-ocular sebaceous carcinoma

A histochemical and immunohistochemical study of five cases of extra-ocular sebaceous carcinoma was performed using formalin-fixed and paraffin-embedded tissue specimens. Histochemically, the clear cells of sebaceous carcinomas were negative with periodic acid-Schiff and alcian blue staining. Immunohistochemically, the tumour cells of sebaceous carcinomas showed positive reactions for epithelial membrane antigen, human milk fat globules subclass 1, human milk fat globules subclass 2 and Leu M1, but did not express carcinoembryonic antigen, breast carcinoma associated antigen, S-100 protein, gross cystic disease fluid protein-15 or Dako M1. These histochemical and immunohistochemical findings were compared with those of other skin cancers which must be distinguished histopathologically from sebaceous carcinoma. We conclude that sebaceous carcinoma can be distinguished from eccrine porocarcinoma, malignant clear cell hidradenoma, extramammary Paget's disease, malignant trichilemmoma, squamous cell carcinoma and basal cell carcinoma by histochemical and immunohistochemical techniques using formalin-fixed and paraffin-embedded tissue specimens.

Lectin-binding profiles for normal skin appendages and their tumors

A histochemical investigation of lectin-binding sites was carried out on formalin-fixed paraffin-embedded sections of 60 skin appendage tumors and adjacent normal skin appendages, using four different biotinylated lectins, peanut agglutinin (PNA), Dolichos biflorus agglutinin (DBA), soybean agglutinin (SBA), and Ulex europaeus agglutinin-1 (UEA-1), and avidin-biotin-horseradish peroxidase labeling. In the secretory segments of eccrine sweat glands, the superficial dark cells showed strong cytoplasmic staining with UEA-1, whereas DBA and SBA strongly stained the plasma membranes of basal clear cells. The acinar cells of apocrine sweat glands revealed sporadic apical membrane staining with all four lectins. In some cases, the luminal membranes of sweat gland ducts showed apical membranous staining with all four lectins. In the hair follicles, the inner root sheath was positive for all four lectins, and the outer root sheath was stained by PNA. The sebaceous ducts, as well as the outer root sheath at the level of sebaceous duct insertion, were also labeled by all four lectins. Sebaceous lobules showed cytoplasmic and membrane staining of mature sebocytes with PNA and SBA. Although sweat gland tumors revealed differences in lectin binding when compared to their corresponding normal tissues, the lectin-binding pattern of pilosebaceous tumors was analogous to the pilosebaceous apparatus.