The use of immunostaining for bcl-2 and CD34 and the lectin peanut agglutinin in differentiating between basal cell carcinomas and trichoepitheliomas

TRPS1: A Marker of Follicular Differentiation

The trichorhinophalangeal syndrome type 1 (TRPS1) immunohistochemical (IHC) stain has increased in use in recent years as a marker for breast carcinomas. The TRPS1 gene is involved in various tissues, including the growth and differentiation of hair follicles. This article seeks to evaluate the IHC expression of TRPS1 in cutaneous neoplasms with follicular differentiation, such as trichoblastoma (TB), trichoepithelioma (TE), and basal cell carcinoma (BCC). IHC studies were performed on 13 TBs, 15 TEs, and 15 BCCs with an antibody against TRPS1. The study found a variable staining expression of TRPS1 in the tumor nests of TB, TE, and BCC. BCCs were distinct in that none of the BCCs demonstrated intermediate or high positivity, while TBs and TEs showed intermediate-to-high positivity in 5/13 (38%) and 3/15 (20%) of cases, respectively. We observed a distinct staining pattern among the mesenchymal cells of TB and TE. We found that TRPS1 highlighted perifollicular mesenchymal cells adjacent to the nests of TB and TE tumor cells. This staining pattern was absent in BCCs, where only scattered stromal cells were positive for TRPS1. Papillary mesenchymal bodies were also highlighted by TRPS1 in TB and TE. TRPS1 stained various parts of the normal hair follicle, including the nuclei of cells in the germinal matrix, outer root sheaths, and hair papillae. TRPS1 may be a useful IHC marker for follicular differentiation.

Significance of androgen receptor and CD10 expression in cutaneous basal cell carcinoma and trichoepithelioma

Differential diagnosis of trichoepithelioma (TE) and basal cell carcinoma (BCC) on the basis of clinical symptoms and laboratory investigations may be difficult in certain patients. The aim of the present study was to compare cluster of differentiation 10 (CD10) and androgen receptor (AR) expression patterns in BCC and TE, to investigate the predictive power of these proteins as markers of the two conditions. A total of 39 cases of BCC and 15 cases of TE were retrieved from the pathology department archives. AR and CD10 immunohistochemistry was performed on all of the specimens; 23 BCC cases displayed focal nuclear AR staining, however, none of the cases demonstrated diffuse nuclear staining and 16 BCC cases were negative for AR staining. Stromal CD10 staining was more common in TE cases than in BCC cases, and peripheral CD10 staining was more common in BCC cases than in TE cases. AR immunostaining of the BCC samples typically appeared as scattered clusters and individual cells. In addition, AR and CD10 staining exhibited varying staining intensities within each samples. Incisional punch biopsy specimens have the potential to present false-negative results. Therefore, AR and CD10 staining of total excision biopsies provides a more accurate differential diagnosis of BCC and TE for cases with difficulties in the histopathological analysis.

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.

What is new in adnexal tumors of the skin?

This article reviews the recent dermatopathology literature regarding cutaneous adnexal neoplasms, with emphasis on new and underrecognized entities, "old entities" with new findings, advances in immunohistochemistry, and new findings in relation to inherited disorders associated with cutaneous adnexal neoplasms.

Glycophenotype evaluation in cutaneous tumors using lectins labeled with acridinium ester

Background. Tumor cells show alterations in their glycosylation patterns when compared to normal cells. Lectins can be used to evaluate these glycocode changes. Chemiluminescence assay is an effective technique for quantitative analysis of proteins, nucleic acids, and carbohydrates due to its high sensitivity, specificity, and rapid testing. Objective. To use histochemiluminescence based on lectin conjugated to acridinium ester (AE) for the investigation of glycophenotype changes in cutaneous tumors. Methods. Concanavalin A (Con A), Peanut agglutinin (PNA), Ulex europaeus agglutinin-I (UEA-I), and Maackia amurensis agglutinin (MAA) were conjugated to acridinium ester. Biopsies of cutaneous tumors and normal skin were incubated with the lectins-AE, and chemiluminescence was quantified and expressed as Relative Light Units (RLU). Results. Actinic keratosis (AK), keratoacanthoma (KA), squamous cell carcinoma (SCC), and basal cell carcinoma (BCC) showed lower expression of α-D-glucose/mannose and α-L-fucose residues compared to normal tissue. Cutaneous tumors displayed higher expression of Gal-β(1-3)-GalNAc residues than normal tissue. AK and SCC exhibited higher expression of Neu5Ac-α(2,3)Gal residues than normal epidermis. KA and BCC showed equivalent RLU values compared to normal tissue. Conclusions. Lectin histochemiluminescence allowed quantitative assessment of the carbohydrate expression in cutaneous tissues, contributing to eliminate the subjectivity of conventional techniques used in the histopathological diagnosis.

Diagnostic utility of immunohistochemistry in distinguishing trichoepithelioma and basal cell carcinoma: evaluation using tissue microarray samples

Trichoepithelioma is a benign neoplasm that shares both clinical and histological features with basal cell carcinoma. It is important to distinguish these neoplasms because they require different clinical behavior and therapeutic planning. Many studies have addressed the use of immunohistochemistry to improve the differential diagnosis of these tumors. These studies present conflicting results when addressing the same markers, probably owing to the small number of basaloid tumors that comprised their studies, which generally did not exceed 50 cases. We built a tissue microarray with 162 trichoepithelioma and 328 basal cell carcinoma biopsies and tested a panel of immune markers composed of CD34, CD10, epithelial membrane antigen, Bcl-2, cytokeratins 15 and 20 and D2-40. The results were analyzed using multiple linear and logistic regression models. This analysis revealed a model that could differentiate trichoepithelioma from basal cell carcinoma in 36% of the cases. The panel of immunohistochemical markers required to differentiate between these tumors was composed of CD10, cytokeratin 15, cytokeratin 20 and D2-40. The results obtained in this work were generated from a large number of biopsies and resulted in the confirmation of overlapping epithelial and stromal immunohistochemical profiles from these basaloid tumors. The results also corroborate the point of view that trichoepithelioma and basal cell carcinoma tumors represent two different points in the differentiation of a single cell type. Despite the use of panels of immune markers, histopathological criteria associated with clinical data certainly remain the best guideline for the differential diagnosis of trichoepithelioma and basal cell carcinoma.

Desmoplastic trichoepithelioma: report of a unique periocular case

In a 58-year-old woman with blepharospasm, a slowly enlarging left inferomedial eyelid lesion developed. It measured 3 × 5 mm and was nonulcerated, well-circumscribed, whitish, upraised, and firm. An initial incomplete excision followed by a total repeated excision revealed small squamous microcysts, often exhibiting calcifications and cords of nonclefting basaloid cells embedded in a scirrhous stroma characteristic of desmoplastic trichoepithelioma (DTE). Immunohistochemical investigations disclosed CD34-positive stromal fibroblasts and many CK20-positive Merkel cells located among the epithelial cells, features absent in mimicking sclerosing basal cell carcinoma (BCC). The tumor has not recurred during 6 months of follow up. Besides BCC, the differential diagnosis chiefly concerns syringoma and microcystic adnexal carcinoma. Surgical therapy should aim at complete excision but does not have to be as extensive or aggressive as that used for morpheic or sclerosing BCC because of its lack of diffusely infiltrating margins.

Basal cell carcinoma: cell of origin, cancer stem cell hypothesis and stem cell markers

Cancer stem cells have recently been described in several high-grade neoplasms. It is still unclear if they also occur in cutaneous malignancies. Cancer stem cells are not identical with somatic stem cells. The presence of tumour stem cells in a neoplasm does not in itself equal that the tumour derives from a somatic stem cell. A cell originally lacking stem cell characteristics could also acquire those features during the course of carcinogenesis and then becomes the clonal founder cell of a tumour. Basal cell carcinoma (BCC) is the most common cutaneous malignancy. A plethora of various stem cell markers has been applied to study its cellular origin. Intriguingly, the anatomical origin of BCC is still uncertain. This review will discuss the various stem cell markers used in BCC and the cellular origin of this tumour, and touches briefly on the possibility of cancer stem cells in BCC. If BCC or other skin cancers harbour tumour stem cells, these cells could be specifically targeted, making use of specific cell surface molecules such as receptor proteins. Novel drugs directed against those receptor proteins could replace currently available shotgun approaches including imiquimod.

Fibroblast-activation protein: a single marker that confidently differentiates morpheaform/infiltrative basal cell carcinoma from desmoplastic trichoepithelioma

Microscopically, differentiating desmoplastic trichoepithelioma from morpheaform/infiltrative basal cell carcinoma can be difficult as both show 'islands and strands of basaloid cells embedded in a sclerotic stroma'. A superficial shave biopsy further compounds the diagnostic conundrum. Although a plethora of immunohistochemical markers have been touted as being of use as adjunct histologic tools, none thus far appears to be consistent and reliable in terms of specificity and/or sensitivity. Fibroblast-activation protein, a type II membrane-bound glycoprotein belonging to the serine protease family, is expressed in the granulation tissue of healing wounds. More recently, it has been identified as a marker of reactive tumor stromal fibroblasts, as it is reportedly selectively expressed in peritumoral stromal fibroblasts of multiple epithelial cancers including cutaneous malignancies such as basal cell carcinoma. Given this, we sought to ascertain the use of fibroblast-activation protein in distinguishing morpheaform/infiltrative basal cell carcinoma from desmoplastic trichoepithelioma. Immunohistochemical staining for fibroblast-activation protein was performed on desmoplastic trichoepithelioma (n=25) and morpheaform/infiltrative basal cell carcinoma (n=25), with the control group comprising scars from reexcision specimens (n=10). As expected, fibroblast-activation protein expression was observed in stromal fibroblasts of all control cases (10 of 10, 100%). Of interest, fibroblast-activation protein expression was observed in peritumoral fibroblasts of all cases of morpheaform/infiltrative basal cell carcinoma (25 of 25, 100%) but not in any cases of desmoplastic trichoepithelioma (0 of 25, 0%). A gradient of fibroblast-activation protein expression was observed in morpheaform/infiltrative basal cell carcinoma with more intense expression noted in fibroblasts abutting the tumor cells, a less intense expression in the distal peritumoral stromal portion, and minimal to loss of expression in adjacent normal tissue. In summary, findings from this study underscore the use of fibroblast-activation protein as a histologic adjunct in confidently differentiating morpheaform/infiltrative basal cell carcinoma from desmoplastic trichoepithelioma.

Bcl-2 and CD10 expression in the differential diagnosis of trichoblastoma, basal cell carcinoma, and basal cell carcinoma with follicular differentiation

BACKGROUND

Both trichoblastoma and basal cell carcinoma (BCC) of the skin are characterized morphologically by the proliferation of basaloid cells; however, BCCs are clinically associated with a more aggressive behavior. An accurate diagnosis of these lesions is essential for effective, timely treatment and appropriate therapeutic decisions.

METHODS

This study includes 40 lesions. Bcl-2 and CD10 immunohistochemistry were performed in all cases and the patterns of expression were analyzed.

RESULTS

Bcl-2 is useful for the detection of BCC with diffuse expression in nests of basaloid cells, but cannot distinguish between BCC with follicular differentiation and trichoblastoma, as both lesions show the same pattern with positive and negative areas. Conversely, CD10 expression can distinguish between trichoblastomas with peritumoral stromal staining and BCCs with epithelial staining. If both stromal and epithelial areas are stained, these cases are classified as BCC with follicular differentiation.

CONCLUSIONS

CD10 is useful for distinguishing between BCC with widespread follicular differentiation and trichoblastomas.

CD10 expression in trichoepithelioma and basal cell carcinoma

BACKGROUND

Trichoepithelioma (TE) is a benign neoplasm that shares both clinical and histologic features with basal cell carcinoma (BCC). However, it is important to distinguish these neoplasms. Limited immunohistochemical stains are available to separate these two tumors.

METHODS

CD10 protein immunohistochemistry was performed on paraffin-embedded biopsies of 13 TE and 23 BCC diagnosed by routine microscopy. Cases were analyzed for pattern of CD10 expression by tumor cells and surrounding stroma.

RESULTS

Twelve of 13 (92%) TE showed positive stromal immunoreactivity. Of these, eight cases also demonstrated positivity of the papilla, and two also showed positivity of the basaloid cells. No TE demonstrated epithelial expression alone. On the other hand, expression of CD10 by basaloid cells was identified in 20 (87%) cases of BCC. Stromal positivity was also identified in three cases of BCC. Condensation of CD10-positive stromal cells around basaloid nests was statistically significant in differentiating TE from BCC (p < 0.0001). Conversely, CD10-positive basaloid cells were seen predominantly in BCC (p < 0.0001).

CONCLUSIONS

This study demonstrates a statistically significant difference in CD10 staining pattern between TE and BCC. Thus, CD10 may be a useful adjunct marker in distinguishing these tumors.

CD34-reactive trichodiscoma

BACKGROUND

Trichodiscomas are rare hamartomas of the dermal portion of the hair disc, a specialized component of the perifollicular mesenchyme. They are usually found as asymptomatic multiple skin-colored papules on the face and extremities and may have an autosomal dominant inheritance pattern. However, a solitary variant has been described.

CASE REPORT

A 78-year-old woman presented with a single, non-pigmented, firm papule on the left tip of the nose, measuring 3.5 mm in diameter.

RESULTS

The histological examination revealed the previously described features of a trichodiscoma. The immunohistochemical analysis showed strong immunoreactivity for CD34 in the spindle cell component. Spindle cells were negative for S-100, HMB-45, Melan-A, EMA, neurofilament, desmin, and Factor XIIIa by immunohistochemistry.

CONCLUSIONS

We report strong reactivity for CD34 in the spindle cell component of a trichodiscoma. We suggest that this lesion be considered in the differential diagnosis of any CD34+ dermal spindle cell proliferation, in which an adjacent epithelial component cannot be entirely excluded.

Angiogenesis and skin carcinomas with skull base invasion: a case-control study

BACKGROUND

Some skin carcinomas may be very aggressive. Intensity of angiogenesis, measured by intratumoral vessel density using expression of CD34, has been associated with tumor aggressiveness. In this study, the expression of CD34 in basal cell carcinomas ( BCCs) and squamous cell carcinomas (SCCs) with skull base invasion was compared with that in tumors with good outcome.

METHODS

Expression of CD34 was graded as mild, moderate, and intense, in 24 BCCs and 11 SCCs with skull base invasion. The control group included 23 BCCs and 10 SCCs.

RESULTS

Intense expression of CD34 was noted in 25.00% of BCCs with skull base invasion, compared with 4.35% in the control group (p =.058). Regarding SCCs, intense expression of CD34 was found in 54.55% of aggressive tumors, compared with 10.00% in the control group (p =.133).

CONCLUSIONS

A trend toward denser microvascular angiogenesis was observed in both BCCs and SCCs with skull base invasion compared with less aggressive controls.

Expression of p27kip1 in basal cell carcinomas and trichoepitheliomas

Immunohistochemical analysis was used to evaluate p27kip1 expression in normal hair follicles and in a series of 39 basal cell carcinomas (BCC) (13 of superficial type, 7 infiltrating, 7 morphea-like, 12 nodular) and 20 trichoepitheliomas (TE) (9 of classic type, 9 immature, 2 desmoplastic). The labeling index (LI) was derived semiautomatically by means of a computer-assisted cellular image analyzer, and statistical analysis was carried out using the Student t test. A positive reaction for p27kip1 was detected in the hair germ papillae, in supramatrical cells, and in the inner pilar sheath, whereas matrical cells and the outer pilar sheath were negative. All BCC and TE cases showed a positive immunoreaction for p27kip1, but the staining pattern was different in the two groups of lesions, being patchy with focal peripheral accentuation in TE and more diffusely dispersed in BCC. The quantitative study showed lower p27kip1 expression in BCC (LI = 27.51 +/- 12.55) than in TE (LI = 45.27 +/- 20.27) (P < 0.0001). Statistically significant differences were also observed between TE subgroups and nodular or infiltrating BCC subtypes. The occurrence of a wide overlap of LI values hampers the practical application of a p27kip1 LI in the differential diagnosis between BCC and TE in difficult cases, however.

Trichoepithelioma papulosum multiplex

Trichoepithelioma papulosum multiplex is an uncommon autosomal dominant disorder in which multiple trichoepitheliomas are seen. Its cause may be a defective tumor suppressor gene. Studies have mapped this gene to the 9p21 locus. However, there is a parallel or identical syndrome of multiple trichoepitheliomas and cylindromas. Within a given family, some members may have cyclindromas whereas others may have trichoepitheliomas or a combination of both. Although preliminary evidence suggests a different gene is responsible, it is possible that TPM may be caused by more than two independent genes, with some cases of TPM due to impairment of the gene for cylindromatosis. This entity, as well as other disorders with multiple appendageal tumors, may require clarification and distinction from TPM.