Immunohistologic differential diagnosis of basal cell carcinoma, squamous cell carcinoma, and trichoepithelioma in small cutaneous biopsy specimens

A Comparative Study of CD56 and Smooth Muscle Actin Expression in Basal and Squamous Cell Carcinomas

ABSTRACT

Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are the 2 most common types of nonmelanoma skin tumors. Clinical or histopathological diagnostic challenges are encountered on occasion. CD56 and smooth muscle actin (SMA) are highly expressed in BCCs. We aimed to investigate the frequency of these markers, along with B-cell lymphoma 2 (Bcl-2) and Ki67. This study was conducted to propose a method that could possibly be of diagnostic value. One hundred twenty-eight BCC and 39 SCC cases were included in this study. CD56, SMA, Bcl-2, and Ki67 immunohistochemical stains were applied. Ninety-nine (77.3%) BCC and 6 (15.4%) SCC cases showed CD56 immunoreactivity. SMA expression was detected in 78.1% of BCC and 5.1% of SCC cases. CD56, SMA, and Bcl-2 expressions were significantly higher in BCC cases. The Ki67 proliferation index was found significantly higher in SCC cases. When basosquamous carcinoma cases were compared with SCC cases, a significant correlation between tumors and expression of CD56, SMA, and Bcl-2 were obtained. CD56 and SMA, in addition to Bcl-2, favor BCC. Ki67 should also be included in the panel to demonstrate the proliferative activity.

Enemy in disguise: A case report of solitary trichoepithelioma initially diagnosed as BCC

INTRODUCTION

Solitary trichoepitheliomas (TE) are benign tumors that are strikingly similar to their malignant counterpart, basal cell carcinoma (BCC).

PRESENTATION OF CASE

An 83-year-old man presented with a 10-year history of a right lower lid skin mass initially diagnosed as BCC. Intraoperatively, an excisional biopsy was performed with primary reconstruction of the skin defect and the specimen was submitted for histopathology processing. Eventually, histopathology findings suggested the diagnosis of benign hair follicle tumor. The postoperative results were aesthetically pleasing and the integrity of the lower lid was preserved.

DISCUSSION

Despite being rare, benign solitary TE are frequently misdiagnosed as malignant BCC, and vice versa. Oculoplastic surgeons face considerable difficulty distinguishing the two pathologies due to their similar clinical and histological pictures. Hence, excisional biopsy should be considered whenever such discrepancy is confronted to avoid the possibility of recurrence or malignant transformation. Furthermore, immunohistochemical staining could increase the accuracy of diagnosis in such unequivocal findings.

CONCLUSION

Correlation of clinical, dermoscopic and histopathological findings are essential to establish an accurate diagnosis and select the appropriate management. In-depth understanding of eyelid reconstruction principles is mandatory to achieve desirable goals.

CD56 and smooth muscle actin immunoreactivity in basal cell carcinomas: Are they indicators of differentiation or do they hold a diagnostic use?

BACKGROUND

Basal cell carcinoma (BCC) is the most common cutaneous malignancy and may show various differentiations. The possible pluripotent stem cell lineage of BCCs, whose origins are controversial today, is thought to be the main reason for the different morphologies. The aim of the study is to evaluate the expression of some neuroendocrine and smooth muscle markers of differentiation in BCCs and investigate the relationship between histopathologic subtypes and recurrence.

METHODS

A total of 128 cases diagnosed as BCC in our center were included. Immunohistochemical studies of CD56, synaptophysin, chromogranin-A, smooth muscle actin (SMA), desmin, caldesmon, and Ki67 were applied.

RESULTS

CD56, chromogranin-A, and synaptophysin immunoreactivity were detected in 77.3%, 13.3%, and 0.8% of the cases, respectively. 78.1% showed SMA positivity while no tumor expressed desmin or caldesmon. A correlation between histopathologic recurrence risk groups and CD56 expression was found (p < 0.05).

CONCLUSIONS

CD56 and SMA immunoreactivity is present in the majority of BCCs. However, the available findings do not support neuroendocrine or smooth muscle differentiation. CD56 antigen can be used for prognostic purposes in detecting high recurrence risk tumors. After the investigation of the expression rates of these two antigens in different cutaneous tumors, it may be appropriate to use them for diagnostic purposes in BCCs.

The Multiple Faces of Nodular Trichoblastoma: Review of the Literature with Case Presentation

Trichoblastoma (TB) is a rare biphasic benign adnexal neoplasm originating from follicular germ cells but clinically, it can simulate basal cell carcinoma (BCC), making the diagnosis more difficult. There are several variants of Trichoblastoma and a good knowledge of these is essential for correct diagnosis and management. We report two new cases observed in the last year at our Pathological Anatomy Operative Unit, and conduct a careful review of the literature, from the first description of this lesion by Headington in 1970 to the most recent classifications.

Immunohistochemical expression of Tazarotene-induced Gene 3 in oral squamous cell carcinoma

BACKGROUND

The prognosis of hyperproliferative skin lesions, such as psoriasis, basal cell carcinoma, and non-melanoma skin cancers, is significantly benefited from the levels of tazarotene-induced gene-1 (TIG3) expression and subsequent treatment with tazarotene. Such observations suggest that TIG3 could be used as a biomarker for apoptosis, differentiation, and proliferation. The current study aimed to evaluate the expression of TIG3 in normal oral mucosa (NOM) and oral squamous cell carcinoma (OSCC) compared with normal skin (NS) and skin squamous cell carcinoma (SSCC) using immunohistochemistry.

METHODS

Seventeen cases each of SSCC, OSCC, NOM, and NS were evaluated. Each section was immunohistochemically stained with a rabbit polyclonal TIG3 antibody. The entire procedure was blinded and evaluated by 5 observers. Statistical analysis was performed using the chi-square test.

RESULTS

There was a significant decrease in TIG3 protein expression in OSCC and SSCC compared with that in NOM and NS (P = 0.008). The progressive loss of expression was observed as the grade of both malignancies increased. However, there was no significant difference in the expression among the normal tissue groups and within SCC groups of similar grades.

CONCLUSION

The present study suggests that the loss of TIG3 is an important event in carcinogenesis. TIG3 acts as a regulator of keratinocyte proliferation and terminal differentiation. Therefore, TIG3 could be a potential biomarker to differentiate aggressive and non-aggressive neoplasms.

Utility of Ber-EP4 and MOC-31 in Basaloid Skin Tumor Detection

Ber-EP4 has been the traditional immunostain used for the detection of basaloid skin tumors. Recently, MOC-31 has shown be superior to Ber-EP4 in the detection of basosquamous basal cell carcinoma (BCC) and many centers are now using both Ber-EP4 and MOC-31 antibodies together to detect these lesions. The objective of this study was to compare the utility of using both Ber-EP4 and MOC-31 immunostains in the detection of basaloid skin tumors and to better characterize the previously unknown staining properties of MOC-31 in cutaneous lesions. To do this, 76 basaloid skin tumors stained with both Ber-EP4 and MOC-31 were obtained. Diagnoses included basosquamous BCC, Merkel cell carcinoma, adenoid cystic carcinoma, microcystic adnexal carcinoma, sebaceous carcinoma, trichoepithelioma, trichoblastoma, sebaceous adenoma, sebaceoma, and follicular induction overlying dermatofibroma. The distribution and intensity of Ber-EP4 and MOC-31 staining in these lesions was scored. These scores were analyzed using a truth table, χ test, and Pearson correlation tests. The overall mean and SD of the scores were also obtained. Overall, we found Ber-EP4 and MOC-31 to be statistically equivalent immunostains for the diagnosis of basaloid skin tumors. We recommend the use of only one of these antibodies and favor MOC-31 for the detection of basaloid skin tumors. We also describe MOC-31 staining properties in different cutaneous lesions.

Skin Adnexal Tumors in Plain Language: A Practical Approach for the General Surgical Pathologist

CONTEXT.—

Skin adnexal tumors, those neoplasms deriving from hair follicles and sweat glands, are often a source of confusion amongst even experienced pathologists. Many well-described entities have overlapping features, tumors are often only partially sampled, and many cases do not fit neatly into well-established classification schemes.

OBJECTIVES.—

To simplify categorization of adnexal tumors for the general surgical pathologist and to shed light on many of the diagnostic dilemmas commonly encountered in daily practice. The following review breaks adnexal neoplasms into 3 groups: sebaceous, sweat gland-derived, and follicular.

DATA SOURCES.—

Pathology reference texts and primary literature regarding adnexal tumors.

CONCLUSIONS.—

Review of the clinical and histopathologic features of primary cutaneous adnexal tumors, and the diagnostic dilemmas they create, will assist the general surgical pathologist in diagnosing these often challenging lesions.

Expression of EpCAM in adenoid cystic carcinoma

The mutational landscape of adenoid cystic carcinoma (ACC) is currently being revealed, but further studies are needed to identify biomarkers as therapeutic targets or prognostic factors of ACC. In this study, we investigated the expression of epithelial cell adhesion molecule (EpCAM) in ACCs. We retrospectively collected 83 cases of surgically resected ACCs. Using tissue microarray, we conducted immunohistochemical staining using the anti-EpCAM antibody. EpCAM expression was analysed by intensity score and the total immunostaining score. The positivity was 97.6% (81/83 cases), regardless of the intensity score. A higher histological grade (p = 0.006) and specific tumour location (non-salivary gland origin, p = 0.02) showed a correlation with higher EpCAM intensity. Higher EpCAM expression by total immunostaining score was associated with histological grade (p = 0.004), distant metastasis (p = 0.004) and poorer prognosis (overall survival p = 0.015 and progression-free survival p = 0.033). We suggest EpCAM as a candidate prognostic marker and a putative therapeutic target in ACC. Also, ACCs arising from salivary gland and non-salivary gland sites, respectively, might display different pathophysiologies in which EpCAM could play a role.

A rare development of basal cell carcinoma on trichoepithelioma in a chemical burn scar tissue: A case report

RATIONALE

Trichoepithelioma (TE) is a rare benign skin tumor that originates from the hair follicle epithelium. Although skin lesions arising from scar tissues are mostly malignant, the development of a benign tumor such as TE is a rare event.

PATIENT CONCERNS

A 28-year-old male patient who had a scar on the left cheek which arose 10 years ago because of a chemical burn visited our hospital. Scar revision was performed under local anesthesia.

DIAGNOSIS

Histological examination identified the specimen as a TE with malignant foci suspicious of basal cell carcinoma (BCC) at the lateral margin of the specimen.

INTERVENTIONS

A second stage operation was planned to excise the BCC with a 4 mm margin of the normal skin around the previous lesion.

OUTCOMES

No complication or recurrence was noted during the 1-year follow-up period after surgery, and the appearance of the scar improved.

LESSONS

The correct differential diagnosis between TE and BCC is very important. So follow up at regular intervals is recommended for evaluation of recurrence or transformation into BCC in patients with tumors arising from chemical burn scars. And the concomitant development of TE and BCC should also be considered from a chemical burn scar.

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.

Polymorphous Sweat Gland Carcinoma: An Immunohistochemical and Molecular Study

Polymorphous sweat gland carcinoma is an uncommon low-grade malignant adnexal tumor with a marked predilection for the distal extremities. Histologically, the lesions are characterized by a cellular proliferation showing a combination of growth patterns, including trabecular, solid, tubular, cribriform, or adenoid cystic and pseudopapillary. The immunohistochemical and molecular profile of these tumors has not yet been properly addressed. We have studied 3 cases of polymorphous sweat gland carcinoma using a broad panel of immunohistochemical markers including cytokeratin AE1/AE3, CK5/6, MOC31, p40, p63, p16, chromogranin, synaptophysin, CD56, MIB-1, estrogen receptor, progesterone receptor, androgen receptor, BER-EP4, smooth muscle actin, epithelial membrane antigen, carcinoembryonic antigen, CD117, S100 protein, HBME-1, DOG1, vimentin, and mammaglobin. We also examined for the MYB-NFIB fusion by fluorescent in situ hybridization (ISH) and for human papilloma virus by ISH. Our studies show that cytokeratin AE1/AE3, CK5/6, p40, p63, p16, chromogranin, and CD56 stains were positive in all 3 cases. All 3 cases were negative for MYB-NFIB fusion by fluorescent ISH which rules out adenoid cystic carcinoma. DNA ISH studies for high-risk human papilloma virus were negative in all cases. MIB-1 proliferation index was very high (30%-70% nuclear positivity), supporting a malignant phenotype. The positivity for chromogranin and CD56 suggests partial neuroendocrine differentiation. The differential diagnosis includes metastases from internal malignancies, basal cell carcinoma, and other benign and malignant adnexal neoplasms such as adenoid cystic carcinoma, ductal eccrine carcinoma, and microcystic carcinoma. Positivity for p16 in combination with chromogranin and CD56 may be potentially good markers for differentiating this tumor from other adnexal tumors.

CD10, TDAG51, CK20, AR, INSM1, and Nestin Expression in the Differential Diagnosis of Trichoblastoma and Basal Cell Carcinoma

BACKGROUND

Trichoblastoma (TB) and basal cell carcinoma (BCC) are 2 different neoplasms composed of basaloid cells and have overlapping histopathological features. We compared the immunoexpression of CD10, T-cell death-associated gene 51 (TDAG51), cytokeratin 20 (CK20), androgen receptor (AR), insulinoma-associated protein 1 (INSM1), and nestin for the differential diagnosis of these tumors.

MATERIALS AND METHODS

We assessed a total of 27 BCC and 27 TB cases, including 4 TB lesions in nevus sebaceous and 3 malignant TB lesions for CD10, TDAG51, CK20, AR, INSM1, and nestin expression.

RESULTS

Staining for CK20, TDAG51, INSM1, and stromal CD10 was significantly more common in TB cases than in BCC cases ( P < .001). Epithelial CD10 and AR staining was significantly more common in BCC cases than in TB cases ( P < .001). The difference between the groups for nestin staining was not significant ( P > .05). Stromal CD10 staining was the most sensitive marker (96.3%) and INSM1 the least sensitive (55.6%) marker for TB. TDAG51 showed 100% specificity for TB. A larger number of CK20 positive cells was found in the cases associated with nevus sebaceous than in the other TBs.

CONCLUSION

All the selected markers except nestin were useful for the differential diagnosis between TB and BCC. CD10 and TDAG51 were more useful than the other markers. The use of CK20 could be preferred in nevus sebaceous lesions. INSM1 was less effective in highlighting Merkel cells within the lesion than CK20.

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.

Trichoepithelioma Arising in an Ovarian Mature Cystic Teratoma

Here, we report an extremely rare case of trichoepithelioma (TE)-a benign epithelial tumor originating from the outer root sheath of a hair follicle-arising in an ovarian mature cystic teratoma (MCT) with fluorodeoxyglucose-positron emission tomography (FDG-PET) findings. A 48-year-old Japanese woman presented to our hospital for her annual follow-up of adenomyosis. Ultrasonography and magnetic resonance imaging revealed a left ovarian tumor with irregular-shaped septum, which was suspicious of malignancy. However, tumor marker levels were within normal range. On FDG-PET, the maximum standardized uptake value (SUVmax) of the tumor was 2.9. Laparotomy with left salpingooophorectomy was performed. Pathologic examination revealed the probability of TE, rather than basal cell carcinoma (BCC), arising in an ovarian MCT. After five years of follow-up, the patient had no sign of recurrence. The FDG-PET SUVmax was low in TE, as with other benign tumor. However, future investigation is needed to evaluate the findings of FDG-PET imaging in TE cases.

Fibroepithelioma of Pinkus Revisited

Background

Fibroepithelioma of Pinkus (FeP) is considered a variant of basal cell carcinoma (BCC); however, in the past 20 years, some researchers have argued for its classification as a trichoblastoma. Recently, use of a new immunostaining marker and further dermoscopic characterization of FeP have advanced the debate about its proper classification.

Purpose

A review of the evidence for and against classification of FeP as BCC or trichoblastoma is presented.

Methods

Using PubMed, the term FeP was searched and relevant citations were assessed. Additional relevant articles were identified from references of key papers.

Results

FeP shares characteristics of both trichoblastoma and BCC.

Conclusion

Derived from the same cell type, BCC and trichoblastoma may be best considered as representing opposite ends of a spectrum of differentiation, with FeP deserving an intermediate classification.

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.

Coordinate expression of cytokeratins 7 and 14, vimentin, and Bcl-2 in canine cutaneous epithelial tumors and cysts

Forty-seven canine cutaneous epithelial tumors and cysts were examined to determine coordinate expression of cytokeratins 7 (CK7) and 14 (CK14), vimentin, and Bcl-2 using commercially available antibodies. Within non-affected normal skin adjacent to tumors or cysts, CK7 expression was observed in luminal cells in apocrine glands; CK14 expression was observed in the stratum basale, stratum spinosum, stratum granulosum, basal layer of outer root sheath, sebaceous glands, and myoepithelial cells of apocrine glands; vimentin expression was observed in dermal papilla and scattered non-epithelial cells within the epidermis; and Bcl-2 expression was observed in scattered non-epithelial cells in the epidermis and some apocrine glands. The pattern of expression of CK7 and CK14 in cases of adenocarcinoma of the apocrine gland of the anal sac (CK7+/CK14-) and hepatoid gland tumors (CK7-/CK14+) may prove useful for diagnostic purposes. Loss of expression of CK14 and vimentin, identifying myoepithelial cells, was observed in apocrine and ceruminous adenocarcinomas. Differences in patterns of expression of Bcl-2 were observed between infundibular keratinizing acanthomas compared to trichoepitheliomas.

Multiple Familial Trichoepithelioma with an Adjacent Basal Cell Carcinoma, Transformation or Collision - A Case Report and Review of Literature

Trichoepithelioma 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 skin disease. Malignant transformation is very rare. We describe here a case that developed malignant neoplasm in a setting of multiple trichoepithelioma.

Basal cell carcinoma vs basaloid squamous cell carcinoma of the skin: an immunohistochemical reappraisal

Typical cutaneous basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are morphologically dissimilar. It is well known, however, that poorly differentiated SCC may assume a basaloid phenotype, complicating the histologic distinction between these 2 neoplasms. Selected immunohistochemical stains have been used in the past to aid in that differential diagnosis. In the current study, additional markers were evaluated to determine whether they would be helpful in that regard. Twenty-nine cases of metatypical (squamoid) BCC (MBCC) and 25 examples of basaloid SCC (BSCC) were studied using the antibodies Ber-EP4 and MOC-31 as well as a plant lectin preparation from Ulex europaeus I (UEA-1). The resulting immunostains were interpreted independently by 3 pathologists, and the results showed that MBCCs demonstrated strong and diffuse staining for Ber-EP4 (25/29) and MOC-31 (29/29). In contrast, BSCCs tended to be only sporadically reactive for both markers (4/25 and 1/25 cases, respectively). Labeling for UEA-1 was observed in almost all BSCCs (24/25), but only 6 of 29 cases of MBCC showed limited, focal staining with that lectin. These data suggest that MOC-31 is a useful marker in the specified differential diagnosis, especially when used together with UEA-1.

The importance of cytokeratin 19 expression in the differentiation of Basal cell carcinoma and trichoepithelioma

INTRODUCTION

Basal cell carcinoma (BCC) is the most common skin neoplasm reported in human. On the other hand, trichoepithelioma (TE) is a rare, benign tumour of skin adnexa. The differentiation of BCC and TE may be difficult since their morphological findings are similar. In a few studies, it has been determined that undifferentiated basaloid cells are highly positively stained with cytokeratin 19.

AIM

The aim of this study was the comparison of cytokeratin 19 expression in cases of BCC and TE.

MATERIALS AND METHODS

Sections of skin tissues of 17 TE, 25 BCC and 12 non-neoplastic cases were used for cytokeratin 19 (CK19) immunohistochemical staining.

RESULTS

Staining with CK19 of the BCC cases gave 15(60%) diffuse, 7 (28%) focal and 3 (12%) negative staining. On the other hand, among TE cases, 2 (12%) gave diffuse, 5 (29%) focal and 10 (59%) negative staining with CK19. In the non-neoplastic skin tissue samples, while positive staining with cytokeratin 19 in the outer root sheath of hair follicles and sweat glands were observed, there was no staining in basal layers.

CONCLUSION

CK19 expression may be helpful in the differential diagnosis of BCC and TE especially in small skin biopsy samples in which morphologic differentiation is difficult.

Face Basosquamous Carcinoma, a Case Report

Face basosquamous or metatypical carcinoma is a rare and controversial form of skin cancer. It is characterized by increased incidence of recurrence and distant metastases. We present the case of a patient of 71 years with an ulcerative lesion of 3/4 cm in the nasal pyramid. The injury occurred due to trauma to the nasal pyramid, produced 13 years ago. After investigation, which included ORL examination, imaging and oncology exam, surgery was decided to completely ablate tumor formation. The resulted defect of 4/5 cm was covered by mobilizing a forehead flap based on right supratrohleare artery pedicle. Histopathological examination revealed the diagnosis of basosquamous or metatypical carcinoma. The patient was referred to the oncology service for treatment.

Noninvasive monitoring of basal cell carcinomas treated with systemic hedgehog inhibitors: pseudocysts as a sign of tumor regression

BACKGROUND

Oral hedgehog inhibitors (HHIs) have shown significant efficacy in the treatment of basal cell carcinoma (BCC). The evaluation of tumor regression has been performed using clinical photography and radiographic scans. Noninvasive imaging techniques, such as reflectance confocal microscopy (RCM) and high-definition optical coherence tomography (HD-OCT), have been shown to be valuable in detecting BCC in the skin.

OBJECTIVE

We monitored HHI-treated BCC using RCM and HD-OCT in vivo and correlated morphologic changes seen on imaging to changes in traditional histopathology.

METHODS

Six BCCs in 5 patients receiving HHIs (vismodegib or sonidegib) were examined by RCM and HD-OCT before and during treatment. Characteristic features were compared to histopathologic findings, including immunohistochemical analysis.

RESULTS

Characteristic features of BCC in RCM and HD-OCT decreased or disappeared completely during HHI treatment. Half of the clinically complete responding tumors still featured tumor residue. Pseudocystic structures ("empty" tumor nests in imaging) and widespread fibrosis (coarse bright fibers) were new findings and could be confirmed by histopathology.

LIMITATIONS

Our study was limited by the number of tumor samples and imaging timepoints.

CONCLUSION

Using RCM and HD-OCT, HHI-induced regression of BCC can be visualized noninvasively in the skin. The formation of pseudocysts and fibrosis were characteristic signs of BCC response to HHIs.

Multiscale BerEp4 molecular imaging of microtumor phantoms: toward theranostics for basal cell carcinoma

Basal cell carcinoma (BCC), the most common cancer in humans, appears macroscopically and microscopically similar to many other skin lesions, which makes differential diagnosis difficult. We are developing an approach for quantitative molecular imaging of BerEP4, a transmembrane biomarker for BCC, with the goal of increasing the precision and accuracy of diagnosis. This pilot study was conducted to assess the affinity and selectivity of BerEp4 antibody and assess its possible use in designing theranostic probes for BCC. We provide evidence that our photon-counting fluorescence macrodetection system can recover specific signal increases from a film/pellet phantom. Additionally, we show that a two-photon excited fluorescence /backscatter confocal microscopy system can image BerEP4 antibody/antigen complex on the surface of BerEP4-expressing cancer cells in three dimensions. Based on the initial results, BerEP4 seems to be a promising biomarker for molecular imaging of BCC. To prepare BerEP4 for eventual theranostic use, we examined the feasibility of a combined macro-/micro-optical approach to imaging BCC with various histologies. These optical methods, endowed with the ability to monitor treatment in real time, may open an opportunity for noninvasive diagnosis, treatments, and follow-up.

BerEp4, Cytokeratin 14, and Cytokeratin 17 Immunohistochemical Staining Aid in Differentiation of Basaloid Squamous Cell Carcinoma From Basal Cell Carcinoma With Squamous Metaplasia

Context.—Basaloid squamous cell carcinoma (bSCC) is an uncommon variant of squamous cell carcinoma, which may overlap histologically with basal cell carcinoma with squamous metaplasia (BCCm).

Objective.—To aid in the differentiation of these neoplasms using immunohistochemical staining because of the worse prognosis associated with bSCC.

Design.—Using immunohistochemical techniques, we investigated BerEp4, cytokeratin 17 (CK17), and cytokeratin 14 (CK14) protein expression in 25 cases of bSCC (8 cutaneous [32%], 12 aerodigestive tract [48%], and 5 lymph node metastases [20%]) and 43 cases of BCCm (39 cutaneous [91%], and 4 metastases [9%]). An immunoreactivity score was assigned using the percentage of tumor cells staining and the pattern of expression. Interobserver agreement for 2 independent pathologists was assessed using a κ coefficient.

Results.—The mean percentage of staining was significantly higher in BCCm, compared with bSCC (BerEp4, P = .006; CK17, P &lt; .001; CK14, P &lt; .001; unpaired t test), with 58% of BCCm cases (25 of 43) displaying diffuse staining for all markers, and nearly all (98%; 42 of 43) displaying diffuse staining for CK17 and CK14. In contrast, no bSCC cases (0%) displayed diffuse staining for all 3 markers, and only 8% (2 of 25) displayed diffuse staining for CK17 and CK14. High interobserver agreement was determined.

Conclusions.—BerEp4 alone is unreliable for differentiation between BCCm and bSCC, and the addition of either CK14 or CK17 will augment the sensitivity and negative predictive value of BerEp4 staining in BCCm and bSCC diagnosis.

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.

Use of Ber-EP4 and Epithelial Specific Antigen to Differentiate Clinical Simulators of Basal Cell Carcinoma

EpCam is a transmembrane epithelial adhesion molecule present on all non-squamous epithelial cells. It is often overexpressed in certain carcinomas, such as breast and colon, and in dermatology, eg, basal cell carcinoma (BCC). Various monoclonal antibodies have been used to detect EpCam, including BerEP4 and epithelial specific antigen. We compared anti-EpCam clones, BerEP4, and epithelial specific antigen clone VU-1D9. One hundred and twelve lesions were stained with both antibodies. All basal cell carcinomas stained uniformly and strongly positive with both antibodies. Diffuse positive staining was also seen in all trichoepitheliomas and merkel cell carcinomas. Focal positive staining was seen in squamous cell carcinoma and benign sebaceous neoplasms. Clone VU-1D9 was more likely to produce focal positive staining as compared to BerEP4. This focal positive staining of sebaceous neoplasms and squamous cell carcinomas is a potential diagnostic pitfall.

Simulators of squamous cell carcinoma of the skin: diagnostic challenges on small biopsies and clinicopathological correlation

Squamous cell carcinoma (SCC) is a common and important primary cutaneous malignancy. On skin biopsies, SCC is characterized by significant squamous cell atypia, abnormal keratinization, and invasive features. Diagnostic challenges may occasionally arise, especially in the setting of small punch biopsies or superficial shave biopsies, where only part of the lesion may be assessable by the pathologist. Benign mimics of SCC include pseudoepitheliomatous hyperplasia, eccrine squamous syringometaplasia, inverted follicular keratosis, and keratoacanthoma, while malignant mimics of SCC include basal cell carcinoma, melanoma, and metastatic carcinoma. The careful application of time-honored diagnostic criteria, close clinicopathological correlation and a selective request for a further, deeper, or wider biopsy remain the most useful strategies to clinch the correct diagnosis. This review aims to present the key differential diagnoses of SCC, to discuss common diagnostic pitfalls, and to recommend ways to deal with diagnostically challenging cases.

Basal cell carcinoma in a dog with chronic solar dermatitis

A seven-year-old, entire male, American Staffordshire bull terrier was diagnosed with chronic solar dermatitis and basal cell carcinoma, based on physical examination, cutaneous cytology and histopathology. Immunohistochemistry revealed that the tumour cells did not express p53. To the authors' knowledge this is the first reported case of canine basal cell carcinoma developing as a complication of chronic solar dermatitis.

BerEP4 is widely expressed in tumors of the sweat apparatus: a source of potential diagnostic error

BACKGROUND

A 63-year-old man presented with an ulcerated nodule with a rolled pearly edge on his back. A punch biopsy showed diffuse strong BerEP4 expression and retraction artifact. Consequently the tumor was diagnosed as a basal cell carcinoma but on excision the tumor proved to be a porocarcinoma. Although Jimenez et al. reported BerEP4 expression in porocarcinoma, this result is not widely appreciated. This observation prompted us to investigate BerEP4 expression in sweat apparatus tumors.

METHODS

Immunocytochemistry was performed using Dako monoclonal mouse BerEP4 with Ventana Benchmark XT immunostainer. Omission of the primary antibody served as a negative control.

RESULTS

Fourteen of 26 porocarcinomas had at least focal BerEP4 expression and two were diffusely and at least focally strongly positive. Seven of seven chondroid syringomas stained diffusely positive, with strong ductal expression; the single chondroid syringocarcinoma was negative. Five of 6 poromas and two of two hidradenomas had focal expression, and staining particularly highlighted the ducts, a co-localization also apparent in the four spiradenomas and three cylindromas. The single primary mucinous carcinoma had diffuse strong BerEP4 expression.

DISCUSSION

This case and pilot study shows that BerEP4 expression is common in these selected sweat apparatus tumors, and staining may be strongly so. This observation should be borne in mind in clinical practice.

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.

Metastatic basal cell carcinoma of the posterior neck: case report and review of the literature

Although primary basal cell carcinoma (BCC) represents an extremely common malignancy, metastases derived from BCC are exceedingly rare. The prognosis for metastatic BCC is poor, and little consensus exists regarding predictive factors or optimal treatment strategies. Here, we present the case of a 63-year-old man with BCC of the neck who subsequently developed multiple metastases to subcutaneous tissue, lymph nodes, and the parotid gland. Risk factors and clinical features of metastatic BCC are reviewed, as is the relationship of histopathologic subtype to metastatic behavior. Current chemotherapeutic and targeted therapies also are discussed in the context of recent advances in molecular biology.

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.

Ber-EP4 is a useful marker for follicular germinative cell differentiation of cutaneous epithelial neoplasms

Ber-EP4 is a monoclonal antibody that recognizes 34-kDa and 39-kDa non-covalently linked glycopolypeptides expressed by most human epithelial cells and carcinomas. In this study, we performed immunohistochemical staining of 31 cases of basal cell carcinoma (BCC); 20 cases of trichoblastoma (TB), including ten cases of nodular type, eight cases of cribriform type (trichoepithelioma) and two cases of columnar type (desmoplastic trichoepithelioma); 16 cases of actinic keratosis (AK); and 10 cases each of Bowen's disease, poroma and seborrheic keratosis. Six cases of BCC and AK were co-lesions of both neoplasms. In normal skin tissue, Ber-EP4 reacted positively with the secretory portion of eccrine glands and follicular germinative cells at the lower end of catagen hairs. Neoplastic cells in 97% of cases with BCC reacted positively with Ber-EP4 in at least 5% of neoplastic cells. Those in 90% with nodular type TB and 50% with trichoepithelioma also reacted positively in at least 5% of neoplastic cells. No cases of poroma, seborrheic keratosis, AK or Bowen's disease were immunohistochemically positive for Ber-EP4 in neoplastic cells. In all six cases with co-lesions of BCC and AK, neoplastic cells of BCC reacted positively with Ber-EP4 and those of AK were negative. Immunohistochemical examination using the Ber-EP4 antibody is a useful tool for diagnosing neoplasms with follicular germinative differentiation, such as TB, TE or BCC, and for differentiating those from squamous cell carcinoma in situ, poroma or seborrheic keratosis.

Expression and role of fibroblast activation protein-alpha in microinvasive breast carcinoma

BACKGROUND

Diagnosis of ductal carcinoma in situ (DCIS) in breast cancer cases is challenging for pathologist due to a variety of in situ patterns and artefacts, which could be misinterpreted as stromal invasion. Microinvasion is detected by the presence of cytologically malignant cells outside the confines of the basement membrane and myoepithelium. When malignant cells invade the stroma, there is tissue remodeling induced by perturbed stromal-epithelial interactions. Carcinoma-associated fibroblasts (CAFs) are main cells in the microenvironment of the remodeled tumor-host interface. They are characterized by the expression of the specific fibroblast activation protein-alpha (FAP-α), and differ from that of normal fibroblasts exhibiting an immunophenotype of CD34. We hypothesized that staining for FAP-α may be helpful in determining whether DCIS has microinvasion.

METHODS

349 excised breast specimens were immunostained for smooth muscle actin SMA, CD34, FAP-α, and Calponin. Study material was divided into 5 groups: group 1: normal mammary tissues of healthy women after plastic surgery; group 2: usual ductal hyperplasia (UDH); group 3: DCIS without microinvasion on H & E stain; group 4: DCIS with microinvasion on H & E stain (DCIS-MI), and group 5: invasive ductal carcinoma (IDC). A comparative evaluation of the four immunostains was conducted.

RESULTS

Our results demonstrated that using FAP-α and Calponin adjunctively improved the sensitivity of pathological diagnosis of DCIS-MI by 11.29%, whereas the adjunctive use of FAP-α and Calponin improved the sensitivity of pathological diagnosis of DCIS by 13.6%.

CONCLUSIONS

This study provides the first evidence that immunostaining with FAP-α and Calponin can serve as a novel marker for pathologically diagnosing whether DCIS has microinvasion.

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.

Basaloid squamous cell carcinoma with 'monster' cells: a mimic of pleomorphic basal cell carcinoma

Pleomorphic giant or 'monster' cells represent a well-recognized yet uncommon finding associated with basal cell carcinoma (BCC), usually of nodular type. We present a case of basaloid squamous cell carcinoma (basaloid SCC) with 'monster' cells that closely mimicked those described in pleomorphic nodular BCC. Clinically, the lesion presented as a fleshy, hyperkeratotic nodule in an 82-year-old woman. Histopathology revealed a basaloid lesion with lobulated borders and focal retraction artifact but a lack of prominent palisading or stromal mucin. There were areas of necrosis and small foci of keratinization. Striking bizarre monstrous pleomorphic nuclei were widely scattered throughout the lesion. Ber-EP4 immunohistochemistry proved to be negative and epithelial membrane antigen (EMA) expression was moderate to strong in 70% of the basaloid epithelium. Monster cells have not previously been highlighted in cutaneous SCC or in its uncommon cutaneous basaloid variant. The prognostic significance of monster cells is unknown but, given the relative paucity of keratinization in basaloid SCC, these lesions should probably be regarded as poorly differentiated. We have not previously encountered an SCC that so closely resembles nodular BCC with pleomorphic monster cells and believe that this is the first such report in the literature.