Trichoepithelioma Research Articles

Immunohistochemical analysis of the mechanistic target of rapamycin and hypoxia signalling pathways in basal cell carcinoma and trichoepithelioma.

BackgroundBasal cell carcinoma (BCC) is the most common cancer in Caucasians. Trichoepithelioma (TE) is a benign neoplasm that strongly resembles BCC. Both are hair follicle (HF) tumours. HFs are hypoxic microenvironments, therefore we hypothesized that hypoxia-induced signalling pathways could be involved in BCC and TE as they are in other human malignancies. Hypoxia-inducible factor 1 (HIF1) and mechanistic/mammalian target of rapamycin (mTOR) are key players in these pathways.ObjectivesTo determine whether HIF1/mTOR signalling is involved in BCC and TE.MethodsWe used immunohistochemical staining of formalin-fixed paraffin-embedded BCC (n = 45) and TE (n = 35) samples to assess activity of HIF1, mTORC1 and their most important target genes. The percentage positive tumour cells was assessed manually in a semi-quantitative manner and categorized (0%, <30%, 30–80% and >80%).ResultsAmong 45 BCC and 35 TE examined, expression levels were respectively 81% and 57% (BNIP3), 73% and 75% (CAIX), 79% and 86% (GLUT1), 50% and 19% (HIF1α), 89% and 88% (pAKT), 55% and 61% (pS6), 15% and 25% (pMTOR), 44% and 63% (PHD2) and 44% and 49% (VEGF-A). CAIX, Glut1 and PHD2 expression levels were significantly higher in TE when only samples with at least 80% expression were included.ConclusionsHIF and mTORC1 signalling seems active in both BCC and TE. There are no appreciable differences between the two with respect to pathway activity. At this moment immunohistochemical analyses of HIF, mTORC1 and their target genes does not provide a reliable diagnostic tool for the discrimination of BCC and TE.

Solitary trichoepithelioma in an 8-year-old child: clinical, dermoscopic and histopathologic findings

Solitary trichoepithelioma (TE) is a rare, benign tumor of follicular origin that in certain cases is difficult to differentiate from basal cell carcinoma (BCC). We report the case of an 8-year-old girl with a pale pink, soft lesion on the neck. The clinical image of the lesion was equivocal, while some dermoscopic findings—blue-gray globules and arborizing vessels—could not exclude the presence of BCC from the differential diagnosis, although that would have been a very unlikely case considering the age of the patient. The histopathologic examination established the diagnosis of TE. Given the occasion of this challenging case we try to list the key clinical, dermoscopic and histopathological characteristics of TE and BCC in order to elucidate the differential diagnosis of these two entities.

Marcadores de inmunohistoquímica para el diagnóstico diferencial entre el carcinoma basocelular y el tricoepitelioma

IntroductionBasal cell carcinoma (BCC) is a malignant neoplasm that can be confused clinically and histologically with trichoepithelioma (TE), a benign epithelial tumor with different biologic behavior and requiring distinct treatment. ObjectiveTo determine the usefulness of immunohistochemical markers in the differential diagnosis between BCC and TE. Material and methodsThis study included 35 patients with BCC and 18 patients with TE. In all patients, immunohistochemical analysis was performed of the markers CD34, CD10, BCL -2, CK20, D2-40, Ki67, and P53. ResultsImmunohistochemical expression of CK20 and D2-40 was statistically different in BCC and TE. For the diagnosis of TE, CK20 had a sensitivity of 33.33% and a specificity of 100%, while D2-40 had a sensitivity of 61.11% and a specificity of 74.29%. ConclusionsThe correlation between clinical data and morphological findings with routine microscopy (hematoxylin and eosin) remains the main diagnostic tool for the differential diagnosis between BCC and TE. However, CK20 and D2-40 could provide additional diagnostic information.

Fibroblast-activation protein: valuable marker of cutaneous epithelial malignancy

Fibroblast-activation protein (FAP) is a key protein that is characteristically expressed by carcinoma-associated fibroblasts (CAFs). It has been shown to be expressed in CAFs of 90% of internal epithelial cancers as well as cutaneous epithelial malignancies. We have recently shown that this marker is useful in differentiating between morpheaform/infiltrative BCC from desmoplastic trichoepithelioma (TE). Given this, we sought to assess FAP expression in both benign and malignant cutaneous epithelial entities. Immunohistochemical FAP staining was performed on BCC (n=26), SCC (n=26), porocarcinoma (n=10), metastatic adenocarcinoma (n=12), keratoacanthoma (KA) (n=16), TE (n=14), pseudoepitheliomatous hyperplasia (n=15), poroma (n=15), syringoma (n=10), and chondroid syringoma (n=6). Control group consisted of scars (n=10). FAP expression was observed in all scars and all malignant entities, but not in any of the benign cases. Interestingly, ten KA cases exhibited positivity, whereas six were negative. In summary, FAP is a reliable marker of cutaneous epithelial malignancy.

The Role of Bcl-2, CD10 and CD34 Expression in Differentiation between Basal Cell Carcinoma and Trichoepithelioma

Background: Basal cell carcinoma (BCC) and trichoepithelioma (TE) have some similarities clinically and histologically. The aim of this work is to evaluate the role of Bcl-2, CD10 and CD34 in differentiation between BCC and TE. Methods: The immunohistochemical expression of Bcl-2, CD10 and CD34 was evaluated in 20 BCCs and 12 TEs in a retrospective study. The localization of these markers in tumor and stromal cells was determined and comparison between BCC and TE was done. Immunohistochemistry for Bcl-2, CD10 and CD34 was performed on sections obtained from formalin-fixed, paraffin-embedded blocks. Bcl-2, CD10 and CD34 immunoreactivity in the stromal and/or tumor cells was determined as follows: negative (0); 1+ (10% - 50% positive cells); and 2+ (>50% positive cells). Results: In BCC (20 cases), the expression of Bcl-2 in stromal cells showed (0) immunoreactivity in 8 cases (40%), (1+) immunoreactivity in 7 cases (35%), and (2+) immunoreactivity in 5 cases (25%). Tumoral cells showed diffuse positivity in 20 out of 20 cases (100%), (1+) immunoreactivity in 5 cases (25%) and (2+) immunoreactivity in 15 cases (75%). On the other hand, the expression of Bcl2 in TE, 4 cases showed positive stromal cells out of 12 (33.33%), (1+) immunoreactivity in 2 cases (16.6%) and (2+) immunoreactivity in 2 cases (16.6%), and 8 cases showed no immunoreactivity. Tumoral cells showed positivity in 12 out of 12 cases (100%), (1+) immunoreactivity in 5 cases (41.6%), (2+) immunoreactivity in 7 cases (58.3%). In BCC cases, the expression of CD10 was noted in stromal cells in 8 out of 20 cases (40%), 5 cases showed positivity in stromal and basaloid cells and 3 cases showed positivity in stromal cells only, and 12 cases showed no immunoreactivity (60%). Tumor cells showed positivity in 11 cases out of 20 (55%), (1+) immunoreactivity in 6 cases (30%), (2+) in 5 cases (25%), and 9 cases showed no immunoreactivity (45%). On the other hand, the expression of CD10 in TE 7 cases showed positive stromal cells out of 12 (58.33%), (1+) immunoreactivity in 5 cases (41.6%) and (2+) in 2 cases (16.6%), and 5 cases showed no immunoreactivity (41.66%). Tumor cells showed positivity in 5 cases out of 12 (41.66%), (1+) immunoreactivity in 4 cases (33.33%) and (2+) in 1 case (8.3%), and 7 cases showed no immunoreactivity (58.33%). In BCC cases, the expression of CD34 was noted in stromal cells in14 cases out of 20 cases (70%), (1+) immunoreactivity in 10 cases (50%) and (2+) in 4 cases (20%), and 6 cases showed no immunoreactivity (30%). On the other hand, the expression of CD34 in TE, 10 cases showed positive stromal cells out of 12 (83.33%), (1+) immunoreactivity in 6 cases (50%) and (2+) in 4 cases (33.33%), and 2 cases showed no immunoreactivity (16.6%). Tumor cells showed no immunoreactivity for CD 34 in both BCC and trichoepithelioma, (100%) negative tumor cells. Significant difference of tumor\stromal cells immunoreactivity for Bcl-2 and CD34 in both BCC and TE but it was insignificant for CD10. Conclusion: We conclude that Bcl-2 CD10, CD34 are useful markers in the differential diagnosis of BCC versus TE.

Multiple Trichoepitheliomas Associated With a Novel Heterozygous Mutation in the CYLD Gene as an Adjunct to the Histopathological Diagnosis

Multiple trichoepitheliomas (TEs), especially in the familial setting, have been associated with germline heterozygous mutations in the CYLD gene. Heterozygous germline CYLD mutations and loss of heterozygosity of the CYLD gene in the TE tumor cells have been recently demonstrated in some of the multiple TE cases irrespective of a family history. The histopathological differential diagnosis of TE from basal cell carcinoma may be difficult especially in cases with multiple TEs. Immunohistochemical markers may be used, although some with conflicting results. We describe a 35-year-old woman with multiple facial TEs, in whom the molecular genetic analysis revealed a novel heterozygous c.1843delT mutation in the CYLD gene. This frameshift mutation was also present in a heterozygous state in the TE tumor cells. The demonstration of a novel CYLD mutation was used as an adjunct to the histopathological diagnosis in this case.

Basaloid tumors in nevus sebaceus revisited: the follicular stem cell marker PHLDA1 (TDAG51) indicates that most are basal cell carcinomas and not trichoblastomas

Until the 1990s, basal cell carcinoma (BCC) was viewed as the most common epithelial neoplasm developing in association with nevus sebaceus (NS). Currently, trichoblastoma is thought of as the most prevalent basaloid neoplasm in NS. The follicular stem cell marker pleckstrin homology-like domain, family A, member 1 (PHLDA1) also known as T-cell death-associated gene 51 (TDAG51) labels trichoepithelioma (TE) but not BCC. Therefore, we explored its usefulness in basaloid neoplasms developing in NS. We studied immunohistochemically PHLDA1 in 10 nodular BCCs, 11 TEs, 11 trichoblastomas and 25 NS with basaloid tumors. Additionally, we examined the expression of BCC marker BerEP4 and the distribution of Merkel cells that function as surrogate markers for benign follicular neoplasms. Nineteen of the 25 basaloid tumors in NS were PHLDA1-negative comparable to BCC arising de novo and six tumors were PHLDA1-positive comparable to solitary trichoblastomas and TEs. Fewer Merkel cells were seen in BCCs associated with NS when compared with trichoblastoma. BerEP4 did not discriminate between the neoplasms. We raise concern that the unquestioned assessment that basaloid tumors developing in association with NS represent mostly trichoblastomas and not BCC may not be true. This influences clinical care, as it is paramount in the decision of whether to excise these lesions or not.

Immunohistochemical evaluation of p53 and Ki67 expression in skin epithelial tumors.

Background and Aims:The cellular mechanisms responsible for initiating or limiting the tumors including skin types are of great importance. The p53 is a tumor-inhibiting gene which is believed to be defective in many malignant situations. Ki67 is a non-histonic protein which is mainly interfere with the proliferation and has many controlling effects during the cell cycle. Because of their importance in skin tumor cell growth, this study aimed at evaluating the p53 and Ki67 expression in skin epithelial tumors by immunohistochemical method.Materials and Methods:In a descriptive setting, 50 biopsy samples (30 basal cell carcinomas (BCCs), 10 squamous cell carcinomas (SCCs), 8 keratoacanthomas (KAs), and 2 trichoepitheliomas (TEs)) were immunohistochemically evaluated for p53 and Ki67 expression during a 14-month period. The incidence and expression rate of these two variables were separately reported in each group of samples.Results:The expression rate of p53 was 67.77% for the BCCs, 50.20% for the SCCs, and null for the KAs. For both TEs, it was 50%. The expression rate of Ki67 was 57.33% for the BCCs, 47.70% for the SCCs, 37.5% for the KAs, and 0.0% for TEs. The incidence of P53+ cells was 100% and 90% in the BCC and SCC samples, respectively. The both TEs were positive in this regard. The incidence of Ki67+ cells was 100% for the BCC, SCC, and KA samples. The both TEs were negative in this regard.Conclusion:This study showed that the incidence rate of p53- and Ki67-positive cells is very high in skin malignant epithelial tumors. The expression rate of these two variables is comparable with reports in the literature. Further studies with large sample size are recommended to be carried out for KA and TE samples.

The rate and pattern of Bcl-2 and cytokeratin 15 expression in trichoepithelioma and nodular basal cell carcinoma: A comparative study

Context:Histopathological evaluations can differentiate between clinically resembling trichoepithelioma (TE) and basal cell carcinoma (BCC) unless the biopsy specimens are small or superficial. Previous studies used immunohistochemical evaluation for Bcl-2 and cytokeratin 15 (CK15), in attempts to differentiate between these two entities, with heterogeneous findings.Aims:This study intended to compare the rate and patterns of Bcl-2 and CK15 expressions between specimens of TE and nodular BCC.Settings and Design:Case-series including formalin-fixed, paraffin-embedded cutaneous biopsies.Subjects and Methods:Twenty-two BCC and 12 TE specimens were stained for Bcl-2 and CK15 and examined microscopically. The rate and patterns of expressions were compared between the two groups.Statistical Analysis Used:Statistical analysis was performed using the statistical software (SPSS version 16.0; SPSS Inc., Chicago, IL, USA), Pearson Chi-square, or Fisher's exact tests, wherever appropriate.Results:The two groups were comparable for the expression rate and patterns of Bcl-2 (86.4%: 5 central, 14 diffuse in BCC vs. 83.3%: 2 central, 8 diffuse in TE; P = 0.59 and 0.54 for rate and pattern, respectively). The rate of CK15 expression was significantly higher in TE specimens (66.7%: 4 central, 3 diffuse, 1 peripheral vs. 4.5%: 1 central; P < 0.001). The positive likelihood ratio in distinguishing the two neoplasms was 14.7 (95% confidence interval: 2.1-103.7).Conclusions:CK15 but not Bcl-2 staining may help in differentiating between BCC and TE even in BCCs with follicular differentiation.

Multiple familial trichoepithelioma with malignant transformation

Trichoepithelioma (TE) is a benign tumor of follicular origin that presents as small, skin-colored papules predominantly on the face. When more than one family member is affected, the disease is known as multiple familial trichoepithelioma (MFT). It is a rare autosomal dominant (AD) skin disease. Malignant transformation is very rare. We present a case of MFT in a female patient and her father with malignant transformation to basal cell carcinoma (BCC) in the father. We summarized the main histological differential parameters between TE and BCC and applied immunophenotyping for both by administration of Bcl2, CD34, CD10 and androgen receptor (AR) antibodies.

Differentiation between basal cell carcinoma and trichoepithelioma by immunohistochemical staining of the androgen receptor: an overview

Clinical and histopathological differentiation between basal cell carcinoma (BCC) and trichoepithelioma (TE) is a frequent problem. Attempts have been made to identify immunohistochemical markers helpful in differentiating them. A correct diagnosis is important because the tumours are treated differently. Recent studies showed the absence of androgen receptor (AR) expression in benign hair follicle tumours like TE. This study examines whether AR immunostaining is a useful diagnostic test to differentiate between BCC and TE. We randomly selected 75 cases with histological diagnoses of either BCC (subtypes: superficial, nodular or infiltrative) or TE (subtypes: classic or desmoplastic) from the database of the pathology department of Maastricht University Medical Centre. The available haematoxylin &#38; eosin (H&#38;E) slides were reviewed by three independent investigators using predetermined characteristics. Fifty-six slides (38 BCC and 18 TE) with unequivocal histological characteristics of either tumour were used for immunohistochemistry with AR antibodies. Any nuclear expression within the tumour was considered positive. AR expression was present in 5/8 classic TE, 0/10 desmoplastic TE, 22/23 superficial or nodular BCC and in 10/15 infiltrative BCC. Immunohistochemical stain for AR is useful to differentiate between TE and BCC; particularly in desmoplastic TE versus infiltrative BCC (specificity and positive predictive value of 100%).

Multiple (Familial) Trichoepitheliomas: A Clinicopathological and Molecular Biological Study, Including CYLD and PTCH Gene Analysis, of a Series of 16 Patients

Multiple familial trichoepitheliomas (MFT) constitute an autosomally inherited syndrome possibly related to Brooke-Spiegler syndrome (BSS). Although some early studies suggested a role for the PTCH gene on chromosome 9q22.3 in the etiopathogenesis of MFT, recent studies of occasional patients with the MFT clinical phenotype identified mutations in the CYLD gene on chromosome 16q12-q13, a gene responsible for BSS. A systematic investigation of PTCH and CYLD mutations in patients with MFT has never been performed. Our main objective was to collect a reasonably large series of patients with MFT to (1) study the clinicopathological spectrum of the disease, (2) determine whether the PTCH gene is implicated in the pathogenesis of MFT, and if so (3) determine the relative frequency of CYLD and PTCH mutations, (4) establish if there may be any possible genotype-phenotype correlations, and (5) study the spectrum of somatic mutations. Clinical analysis including family histories, histopathological investigations, and molecular genetic studies were performed. There were 9 female and 7 male patients ranging in age from 11 to 63 years. They presented with multiple, small, discrete and sometimes confluent, skin-colored to pink, asymptomatic nodules preferentially located on the face, being especially prominent and confluent in the nasolabial folds and inner aspects of the eyebrows. A total of 66 conventional trichoepitheliomas (TEs) were studied microscopically. Aside from typical features of TE, some also exhibited variant morphological patterns including areas reminiscent of other benign adnexal neoplasms and melanocytic hyperplasia. In none of the 9 patients tested was a germline mutation of the PTCH gene identified. Germline CYLD mutations were detected in 6 of 13 patients tested (identical in 2 unrelated patients) including 2 novel mutations, whereas the remaining 7 individuals showed wild-type alleles. Two patients with germline wild-type CYLD showed, however, a somatic mutation in the gene (1 duplication, 1 substitution mutation). Neither CYLD nor PTCH germline mutations were found in the 5 patients in whom both genes were analyzed. MFT seems to be a phenotypic variant of BSS. The PTCH gene is rarely, if ever, involved in the pathogenesis of MFT. Absence of a germline mutation of the CYLD gene in cases harboring a somatic mutation may be explained by large deletions in the gene or by mutation in intronic sequences or in the promoter region. Considering our 5 patients with no mutation in either gene, the final possibility is that another, as yet undescribed gene (neither CYLD nor PTCH) is implicated in the pathogenesis of some patients with MFT.

O31 Photodynamic therapy (PDT) of basocellular skin carcinoma

Basal cell carcinoma (BCC) is the prototypical basaloid tumour of the skin, but may show various patterns simulating other cutaneous tumours, particularly squamous cell carcinoma and trichoepithelioma (TE). Other challenges are presented by BCC with marked pleomorphism, glandular differentiation, neuroendocrine differentiation, clear cells and sarcomatoid change. Peripheral palisading and retraction (artefact) of the epithelium from the stroma are the most useful features to support a diagnosis of BCC, but can occasionally be seen in other benign and malignant cutaneous neoplasms and are inconspicuous or lacking in some cases of BCC. Increased ‘stromal’ mucin accompanying retraction and peripheral palisading is extremely suggestive of BCC and is rarely seen in other tumour types. Diffuse and strong BerEP4 staining and absence of epithelial membrane antigen staining is characteristic of BCC, and is an immunophenotype rarely encountered in other tumours except for TE. CD10 staining of the basaloid epithelium, in the absence of significant stromal staining, may support a diagnosis of TE-like BCC rather than TE in more organized variants.

Advanced differentiation in trichoepithelioma and basal cell carcinoma investigated by immunohistochemistry against neurofilaments.

Basal cell carcinoma (BCC) and trichoepithelioma (TE) are sometimes diagnostic challenges for the pathologist in terms of their differential diagnosis. Although literature is quite rich in information about histologic and immunohistochemical clues to distinguish the differences between both, no single finding must be completely reliable. Moreover, some consider that TE is a better differentiated follicular tumour, while BCC represents a less developed stage in differentiation. For instance, the latter opinion is supported by the evidence of follicular papillae in TE.The formation of a perifollicular nerve plexus happens later than the formation of the follicular papillae in the development of a normal follicle. The study of the presence of the perifollicular nerve plexus in both tumours which could then provide us with evidence on the stage of differentiation of both tumours. 5 cases of TE and 10 cases of BCC were randomly selected from our archives and an immunohistochemical study for neurofilaments was performed in all the cases.We found a peritumoural nerve plexus in all the cases (TEs and BCCs). Since this plexus is a late sign of differentiation and since both types of neoplasias share it, we conclude that TE and BCC are both terminally differentiated neoplasms. The ability of BCC to infiltrate would have more to do with the acquisition by the tumour of such a property, rather than with a stage of indifferentiation.

Basal cell carcinomas arising within multiple trichoepitheliomas

Although trichoepitheliomas (TEs) are commonly regarded as benign tumors of follicular origin, the natural history of multiple familial trichoepitheliomas (MFT) and their risk for malignancy has been unclear. We describe a 57-year-old male with numerous skin-colored firm papules and plaques present on the central face since 6 years of age. Recently, some lesions had enlarged and ulcerated. Other family members were similarly affected. Biopsies from multiple lesions showed TEs both alone and associated with basal cell carcinoma (BCC) in the same section, suggesting the secondary development of BCCs within TEs. Many prior reports of BCCs arising within TEs in patients with presumed MFT were likely misdiagnosed cases of nevoid BCC. This report is a compelling example of MFT in which BCCs evolved secondarily. Awareness of the potential for the evolution of carcinoma in patients with MFT is important in the management of these patients.

Elastic fiber staining and cytokeratin 15 expression pattern in trichoepithelioma and basal cell carcinoma

Trichoepithelioma (TE) is a benign neoplasm of the skin that resembles basal cell carcinoma (BCC) in its clinical and histological features. In this study, we evaluate the usefulness of elastic fiber staining and cytokeratin 15 expression pattern in terms of distinguishing TE from BCC. Eleven TE and 17 BCC were examined histochemically and immunohistochemically. It was found that BCC contain more elastic fiber than TE, and that more TE show peripheral localization than BCC in cytokeratin 15 expression patterns. The present study shows that elastic fiber staining and cytokeratin 15 expression pattern may aid the differentiation of TE from BCC.

Immunohistochemical Expression of Vascular Endothelial Growth Factor and Vascular Endothelial Growth Factor Receptor Associated with Tumor Cell Proliferation in Canine Cutaneous Squamous Cell Carcinomas and Trichoepitheliomas

The expression of 5 markers associated with angiogenesis was studied in canine squamous cell carcinomas (SCCs) (n = 19) and canine trichoepitheliomas (TCPs) (n = 24). SCCs were assigned histologic grades, and tissue sections from both tumor types were immunohistochemially stained for the expression of vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor-2 (VEGFR-2), as well as intratumoral microvessel density (iMVD), tumor proliferation index (PI), and tumor apoptotic index (AI), using antibodies against VEGF, VEGFR-2, von Willebrand's factor, Ki-67 antigen, and the terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate end-labeling method (TUNEL), respectively. VEGF and VEGFR-2 were detected in 17/19 (89.4%) and 19/19 (100%) SCCs and in 17/24 (70.8%) and 20/24 (83.3%) TCPs, respectively. In SCCs, there was substantial correlation between histologic grade and PI (r = 0.51); and moderate correlation between VEGF and histologic grade (r = 0.43), VEGFR-2 and histologic grade (r = 0.47), VEGF and PI (r = 0.47), and VEGFR-2 and PI (r = 0.47) (Spearman rank correlation coefficient). In TCPs, there was substantial correlation between VEGF and PI (r = 0.51) and a moderate correlation between VEGFR-2 and iMVD (r = 0.36). The median iMVD of SCCs (15.5) was significantly higher than the median iMVD of TCPs (9.05) (P value < .05). It was concluded that VEGF and VEGFR-2 may promote tumor cell proliferation in TCPs and SCCs. An autocrine pathway for VEGF probably operates in canine SCCs and TCPs, as VEGF and VEGFR-2 expression was found in most tumors and was associated with evidence for tumor cell proliferation.

Basaloid skin tumours: Basal cell carcinoma

Basal cell carcinoma (BCC) is the prototypical basaloid tumour of the skin, but may show various patterns simulating other cutaneous tumours, particularly squamous cell carcinoma and trichoepithelioma (TE). Other challenges are presented by BCC with marked pleomorphism, glandular differentiation, neuroendocrine differentiation, clear cells and sarcomatoid change. Peripheral palisading and retraction (artefact) of the epithelium from the stroma are the most useful features to support a diagnosis of BCC, but can occasionally be seen in other benign and malignant cutaneous neoplasms and are inconspicuous or lacking in some cases of BCC. Increased ‘stromal’ mucin accompanying retraction and peripheral palisading is extremely suggestive of BCC and is rarely seen in other tumour types. Diffuse and strong BerEP4 staining and absence of epithelial membrane antigen staining is characteristic of BCC, and is an immunophenotype rarely encountered in other tumours except for TE. CD10 staining of the basaloid epithelium, in the absence of significant stromal staining, may support a diagnosis of TE-like BCC rather than TE in more organized variants.

Expression of class II ?-tubulin in non-melanoma cutaneous tumors

Different combinations of beta-tubulin isotypes contribute to the diverse functions of microtubules (MTs). Class II beta-tubulin (class II tubulin) is up-regulated in differentiated keratinocytes. In contrast, the expression of class II tubulin in follicular differentiation and cutaneous tumors has not been studied. The immunohistochemical expression of class II tubulin was investigated in 117 cutaneous tumors: 30 squamous cell carcinomas (SCCs), seven keratoacanthomas (KAs), 57 basal cell carcinomas (BCCs), 23 trichoepitheliomas (TEs), and in the adjacent non-neoplastic skin. Class II tubulin was expressed in the keratinocytes of the granular layer, melanocytes, hair cortical and cuticular cells, inner root sheath (IRS), companion layer (CL) of the outer root sheath (ORS), and mesenchymal cells with Schwannian or myogenic differentiation. Moreover, class II tubulin expression was increased in the areas of squamous or follicular differentiation in cutaneous tumors. On grading the follicular differentiation or myofibroblastic response with anti-class II tubulin, TE showed follicular differentiation more frequently (p < 0.001) with less of a myofibroblastic response (p = 0.001) than BCC. Class II tubulin expression is closely related to squamous or follicular differentiation and may be helpful in distinguishing most SCCs from KAs and BCC from TE. However, it does not reliably distinguish well-differentiated, crateriform SCC from KA.

Digital image analysis of skin neoplasms evaluated by lectin histochemistry: potential marker to biochemical alterations and tumour differential diagnosis

The present study aims to evaluate, through lectin histochemistry, the alterations in the expression of cell surface carbohydrate between benign and malignant lesions of skin using computer image analysis. Skin fragments were obtained through biopsies and diagnosed as basal cell carcinoma (BCC), epidermoid carcinoma (EpC), trichoepithelioma (TE), keratoacanthoma (KA), seborrheic keratosis (SK) and actinic keratosis (AK). Lectins Con A, WGA, PNA, UEA-I and LTA were used in histochemistry study. Image analysis was carried out in a workstation using OPTIMASTM software system. PNA strong binding pattern to studied tumours evidenced the high expression of D-galactose residues in the epidermal neoplasms when compared to other sugars recognized by the other lectins. Among benign neoplasms, KA presented a high expression of glucose/mannose, a-fucose and D-galactose residues evidenced by the intense staining of Con A (94.7%), LTA (84.2%) and PNA (89.4%), respectively. Malignant tumours showed distinct binding patterns. EpC presented significant binding only by PNA lectin. BCC was differentially stained in comparison to the staining pattern observed in benign lesions such as TE. Qualitative (lectin histochemistry) and quantitative (digital image analysis) data obtained in this study evidenced those lectins are potential markers to biochemical alterations in skin neoplasms.