Metatypical basal cell carcinoma: a clinical review

Surgical Management of Patients with Parotid Involvement from Non-Melanoma Skin Cancer of the Head and Neck

We conducted a retrospective, longitudinal study on a single-center series of patients who underwent parotidectomy in the management of advanced head and neck non-melanoma skin cancer (hnNMSC). The aim of this study was to identify prognostic factors associated with worse outcomes. Forty-one men and nine women were included. The mean age at the time of surgery was 78.9 years. The 5-year overall survival, disease-specific survival, locoregional recurrence-free survival, and distant metastasis-free survival calculated with Kaplan-Meier curves were 39.9%, 56.3%, 58.6%, and 82.1%, respectively. A univariate analysis showed that the status of the margins, facial nerve direct involvement, lymph vascular invasion, and histological grading were associated with worse outcomes (p < 0.05). Positive margins were associated with worse disease-specific survival also in a multivariate analysis (p = 0.001, HR = 32.02, and CIs 4.338 to 351.3). Because the resection in free margins is the most important prognostic factor, early diagnosis or, in the case of advanced disease, extensive surgical resection with concomitant reconstruction is needed. Adjuvant therapy is indicated in selected cases.

Basosquamous Carcinoma: Comprehensive Clinical and Histopathological Aspects, Novel Imaging Tools, and Therapeutic Approaches

Basosquamous carcinoma (BSC), an uncommon and aggressive nonmelanoma skin cancer exhibiting characteristics ranging from basal cell carcinoma (BCC) to squamous cell carcinoma (SCC), is a subject of controversy in terms of its classification, pathogenesis, histologic morphology, biologic behavior, prognosis, and management. This narrative review is based on an electronic search of English-language articles in PubMed that included the terms "basosquamous carcinoma" and/or "metatypical carcinoma of the skin" in their titles. The review aims to succinctly present and assess current data on the epidemiology, clinical presentation, dermoscopic, LC-OCT, and histopathologic characteristics, as well as the genetics and management of BSC, providing insight into this intriguing entity. As a conclusion, dermoscopy, deep incisional biopsies, and immunohistologic techniques should be applied in clinically suspicious lesions to achieve an early diagnosis and better prognosis of this tumor. Surgical treatments, including wide excision and Mohs' micrographic surgery, remain the treatment of choice. Finally, Hedgehog pathway inhibitors and checkpoint inhibitors, must be thoroughly investigated with large controlled trials, since they may offer an alternative solution to irresectable or difficult-to-treat locally advanced cases of basosquamous carcinoma.

Differential Expression of ATM, NF-KB, PINK1 and Foxo3a in Radiation-Induced Basal Cell Carcinoma

Research in normal tissue radiobiology is in continuous progress to assess cellular response following ionizing radiation exposure especially linked to carcinogenesis risk. This was observed among patients with a history of radiotherapy of the scalp for ringworm who developed basal cell carcinoma (BCC). However, the involved mechanisms remain largely undefined. We performed a gene expression analysis of tumor biopsies and blood of radiation-induced BCC and sporadic patients using reverse transcription-quantitative PCR. Differences across groups were assessed by statistical analysis. Bioinformatic analyses were conducted using miRNet. We showed a significant overexpression of the FOXO3a, ATM, P65, TNF-α and PINK1 genes among radiation-induced BCCs compared to BCCs in sporadic patients. ATM expression level was correlated with FOXO3a. Based on receiver-operating characteristic curves, the differentially expressed genes could significantly discriminate between the two groups. Nevertheless, TNF-α and PINK1 blood expression showed no statistical differences between BCC groups. Bioinformatic analysis revealed that the candidate genes may represent putative targets for microRNAs in the skin. Our findings may yield clues as to the molecular mechanism involved in radiation-induced BCC, suggesting that deregulation of ATM-NF-kB signaling and PINK1 gene expression may contribute to BCC radiation carcinogenesis and that the analyzed genes could represent candidate radiation biomarkers associated with radiation-induced BCC.

Basosquamous Cell Carcinoma of the Nipple-Areola Complex-Report of a Case

Basosquamous cell carcinoma (BSCC) is a rare malignancy usually arising on sun-exposed areas of the skin. BSCC is described as a rare variant of Basal cell carcinoma (BCC) which shows clinical and microscopic features of both BCC and of Squamous cell carcinoma (SCC). We report the case of a 70-year-old male with a cutaneous lesion of the nipple-areola complex (NAC); to the best of our knowledge, this is the first ever reported patient with BSCC in this area. The lesion had a fast growth, but, due to the COVID19 crisis, the patient only came to our observation one year after onset of this condition. Physical examination showed a bleeding red ulcerated lesion that involved the NAC, measuring 27 mm × 20 mm. Biopsy showed a BSCC. Pre-operative breast ultrasound scan, mammogram and MRI were all performed before surgery, which consisted of simple mastectomy and sentinel lymph-node biopsy. The patient was discharged home on the 4th post-operative day, and at 18-month follow-up there are no signs or clinical evidence of local recurrence or metastases. Diagnosis of BSCC of the nipple-areola complex requires high index of suspicion and a thorough differential diagnosis, management, and suitable radical treatment due to well described high rates of recurrence and of metastases. Differential diagnosis with similar lesions (e.g., Paget's disease, Bowen's disease, BCC, and SCC) should also be taken into account.

Basosquamous Carcinoma: A Commentary

Simple Summary

Basosquamous carcinoma is a rare, aggressive non-melanoma skin cancer with features that lie between those of basal cell carcinoma and squamous cell carcinoma. A lot of controversy has been raised around the classification, pathogenesis, histologic morphology, biologic behavior, prognosis and management of this tumor. This is a narrative review based on articles published on PubMed in English language which had in their title the terms “basosquamous carcinoma” and/or “metatypical carcinoma of the skin”. The aim of this review was to summarize and evaluate the latest data of the English literature regarding epidemiology, clinical presentation, dermoscopic and histopathologic characteristics, as well as the genetics and management of BSC to better characterize basosquamous skin lesions.

Abstract

Basosquamous carcinoma is a rare, aggressive non-melanoma skin cancer with features that lie between those of basal cell carcinoma and squamous cell carcinoma. A lot of controversy has been raised around the classification, pathogenesis, histologic morphology, biologic behavior, prognosis and management of this tumor. This is a narrative review based on an electronic search of articles published in PubMed in English language which had in their title the terms “basosquamous carcinoma” and/or “metatypical carcinoma of the skin”. The aim of this review was to summarize and evaluate current data regarding epidemiology, clinical presentation, dermoscopic and histopathologic characteristics, as well as the genetics and management of BSC, in order to shed some more light onto this intriguing entity. As a conclusion, dermoscopy, deep incisional biopsies and immunohistologic techniques (Ber-EP4) should be applied in clinically suspicious lesions in order to achieve an early diagnosis and better prognosis of this tumor. Surgical treatments, including wide excision and Mohs’ micrographic surgery, remain the treatment of choice. Finally, vismodegib, a Hedgehog pathway inhibitor, must be thoroughly investigated, with large controlled trials, since it may offer an alternative solution to irresectable or difficult-to-treat, locally advanced cases of basosquamous carcinoma.

Costunolide, a Sesquiterpene Lactone, Suppresses Skin Cancer via Induction of Apoptosis and Blockage of Cell Proliferation

Costunolide is a naturally occurring sesquiterpene lactone that demonstrates various therapeutic actions such as anti-oxidative, anti-inflammatory, and anti-cancer properties. Costunolide has recently emerged as a potential anti-cancer agent in various types of cancer, including colon, lung, and breast cancer. However, its mode of action in skin cancer remains unclear. To determine the anti-cancer potential of costunolide in skin cancer, human epidermoid carcinoma cell line A431 was treated with costunolide. A lactate dehydrogenase assay showed that costunolide diminished the viability of A431 cells. Apoptotic cells were detected by annexin V/propidium iodide double staining and Terminal deoxynucleotidyl transferase mediated dUTP nick end labeling assay assay, and costunolide induced cell apoptosis via activation of caspase-3 as well as induction of poly-ADP ribose polymerase cleavage in A431 cells. In addition, costunolide elevated the level of the pro-apoptotic protein Bax while lowering the levels of anti-apoptotic proteins, including Bcl-2 and Bcl-xL. To address the inhibitory effect of costunolide on cell proliferation and survival, various signaling pathways, including mitogen-activated protein kinases, signal transducer and activator of transcription 3 (STAT3), nuclear factor κB (NF-κB), and Akt, were investigated. Costunolide activated the p38 and c-Jun N-terminal kinase pathways while suppressing the extracellular signal-regulated kinase (ERK), STAT3, NF-κB, and Akt pathways in A431 cells. Consequently, it was inferred that costunolide suppresses cell proliferation and survival via these signaling pathways. Taken together, our data clearly indicated that costunolide exerts anti-cancer activity in A431 cells by suppressing cell growth via inhibition of proliferation and promotion of apoptosis. Therefore, it may be employed as a potentially tumor-specific candidate in skin cancer treatment.

Giant basal cell carcinoma associated with vitiligo

We report a woman with two giant Basal cell carcinomas (BCCs) on the back, the largest with 12 cm in diameter, inside a vitiligo plaque. They were metatypical subtype BCC associated with a nodular subtype area. Thinking of BCC in vitiligo lesion is extremely important. Giant BCC and vitiligo are rare association.

Role and Therapeutic Targeting of the PI3K/Akt/mTOR Signaling Pathway in Skin Cancer: A Review of Current Status and Future Trends on Natural and Synthetic Agents Therapy

The mammalian or mechanistic target of rapamycin (mTOR) and associated phosphatidyl-inositiol 3-kinase (PI3K)/protein kinase B (Akt) pathways regulate cell growth, differentiation, migration, and survival, as well as angiogenesis and metabolism. Dysregulation of these pathways is frequently associated with genetic/epigenetic alterations and predicts poor treatment outcomes in a variety of human cancers including cutaneous malignancies like melanoma and non-melanoma skin cancers. Recently, the enhanced understanding of the molecular and genetic basis of skin dysfunction in patients with skin cancers has provided a strong basis for the development of novel therapeutic strategies for these obdurate groups of skin cancers. This review summarizes recent advances in the roles of PI3K/Akt/mTOR and their targets in the development and progression of a broad spectrum of cutaneous cancers and discusses the current progress in preclinical and clinical studies for the development of PI3K/Akt/mTOR targeted therapies with nutraceuticals and synthetic small molecule inhibitors.

Photodynamic therapy in superficial basal cell carcinoma treatment

Basal cell cancer (BCC) is an epithelial neoplasm that arises from basal cells, which constitute the lower layer of the epidermis. Global statistics have shown the progressive increase in the incidence of skin cancer in several countries. The cumulative exposure to solar radiation (ultraviolet B) in the first two decades of life represents the critical risk for the disease. Preclinical and clinical trials have shown photodynamic therapy (PDT) as a promising innovation for treatment of skin cancers, especially to the non-melanoma group. The authors reviewed trials with photodynamic therapy in superficial basal cell carcinoma with different photosensitizers to better evaluate how PDT modifies the natural history of sBCC. We conclude trials should not assess only the immediate efficacy but the main goal of long-term effectiveness of the protocols in order to generate best evidence for clinical practice.

Eruptive Basaliomas: "Why we have to Perform Surgery?" Or Said Otherwise: "Catch The Metatypical!"

BACKGROUND

Keratinocyte cancers are malignant diseases with a broad incidence of spread which tends to increase during the last couple of decades. The solar radiation plays a dominant role in the occurrence of BCC, but certain genetic phenotypes appear to be risky from an etiological point of view. Metatypical basal cell carcinoma (MTBCC) is a rare variant of BCC which combines the clinical and histological characteristics of BCC and SCC. Clinically they are indistinguishable from the conventional BCC, and only the histological examination can differentiate them. The MTBCC is a histological subtype which is considered more aggressive due to its ability to produce local recurrences or distant metastases.

CASE REPORT

We present a 44-year old patient with multiple BCCs disseminated on the face and body. The biopsy established mixed type histology: three metatypical and four solid BCCs. The lesions were removed via elliptical excision with a field of operational security of 0.5 cm in all directions.

CONCLUSIONS

The eruptive (multiple) BCCs are a challenge about the choice of a therapy option. This is because clinically completely identical tumours show different histopathological characteristics, namely those with a tendency to metastasise. Having in mind one of the hypotheses of metatypical BCC emergence - the improper or inadequate radiotherapy (as a choice of therapy) could trigger the transition of a conventional tumour to a metastasising one, the surgical treatment appears to be the most secure treatment method.

New application of purse string suture in skin cancer surgery

Closure of large wounds may require full-thickness skin grafts, but their use is burdened by donor tissue availability and morbidity; the use of the purse string technique is an elegant way to overcome this problem. The study highlights the gain in terms of graft donor site morbidity and oncological radicality. The study included a group of 47 patients who underwent surgical excision for skin cancer and whose wounds were covered using a purse string suture and a skin graft. Radius of the defect left was measured after the lesion's excision and after the purse string suture. Thereafter, the difference between the initial defect area and the area after purse string suture was calculated. Initial defects ranged from 3.85 to 61.5 cm² . After skin graft, the purse string suture ranged between 2.2 and 40 cm² (mean area = 14 cm² ). Gained area before the graft measured from 1.3 to 21.5 cm² (mean gained area = 7.1 cm² ). Average reduction was 33%. The technique allows a reduction of the size of the area to be grafted and the skin graft donor area, thus increasing the possibility of the feasibility of full-thickness grafts. In addition, it allows an optimal observation both of the area of tumour excision and margins during follow-up controls.

Graviola (Annona muricata) Exerts Anti-Proliferative, Anti-Clonogenic and Pro-Apoptotic Effects in Human Non-Melanoma Skin Cancer UW-BCC1 and A431 Cells In Vitro: Involvement of Hedgehog Signaling

Non-melanoma skin cancers (NMSCs) are the leading cause of skin cancer-related morbidity and mortality. Effective strategies are needed to control NMSC occurrence and progression. Non-toxic, plant-derived extracts have been shown to exert multiple anti-cancer effects. Graviola (Annona muricata), a tropical fruit-bearing plant, has been used in traditional medicine against multiple human diseases including cancer. The current study investigated the effects of graviola leaf and stem extract (GLSE) and its solvent-extracted fractions on two human NMSC cell lines, UW-BCC1 and A431. GLSE was found to: (i) dose-dependently suppress UW-BCC1 and A431 cell growth, motility, wound closure, and clonogenicity; (ii) induce G₀/G₁ cell cycle arrest by downregulating cyclin/cdk factors while upregulating cdk inhibitors, and (iii) induce apoptosis as evidenced by cleavage of caspases-3, -8 and PARP. Further, GLSE suppressed levels of activated hedgehog (Hh) pathway components Smo, Gli 1/2, and Shh while inducing SuFu. GLSE also decreased the expression of pro-apoptotic protein Bax while decreasing the expression of the anti-apoptotic protein Bcl-2. We determined that these activities were concentrated in an acetogenin/alkaloid-rich dichloromethane subfraction of GLSE. Our data identify graviola extracts and their constituents as promising sources for new chemopreventive and therapeutic agent(s) to be further developed for the control of NMSCs.

Basosquamous Carcinoma: A Single Centre Clinicopathological Evaluation and Proposal of an Evidence-Based Protocol

Basosquamous carcinoma (BSC) is an uncommon skin malignancy with significant invasive and metastatic potential. There are currently no clear management guidelines. This study evaluates the management and outcomes of patients diagnosed with BSC over a 7-year period. We present an evidence-based unit protocol for the management of BSC. All patients treated for BSC between 2009 and 2015 were reviewed. Data collected included patient demographics, tumour-specific information, management strategy, presence of recurrence or metastasis, and details of follow-up. 74 patients were identified, making this one of the largest cohorts of BSC patients reported. Mean age at diagnosis was 75.4 years, with a male:female ratio of 1.6:1. The most common tumour site was the head and neck (n=43, 58.1%). All tumours were graded at pT1 (n=51) or pT2 (n=23). Inadequate excision occurred in 17 patients (23%). Mean excision margins were >4mm peripherally and deep. Inadequately excised BSCs were further treated with wide local excision (n=6) or radiotherapy (n=5), or both (n=1). There were no cases of local recurrence or metastatic disease. This study demonstrates a cohort of patients with BSCs that appear less aggressive than previously reported. Current management with surgical excision appears to produce adequate results. However, an evidence-based guideline is still lacking.

Sentinel lymph node metastasis in primary cutaneous basosquamous carcinoma. A cross-sectional study

BACKGROUND AND OBJECTIVES

Basosquamous carcinoma (BSC) is a rare, biologically aggressive tumor. This cross-sectional study aims to define risk factors for subclinical nodal metastasis in primary BSC, and identify the patients who would benefit from routine sentinel node biopsy (SLNB) as part of the initial management.

METHODS

A total of 142 patients, with histologically proven BSC without palpable lymph nodes, underwent SLNB after the initial excision. Clinicopathological features and demographics were analyzed between the patients with detected micrometastasis (SLNM) and those with negative SLN.

RESULTS

In 7.7% patients, subcapsular and <0.1 mm SLNM were found. The frequency of SLNM was 0.9%, 11.8%, and 80.0% in patients with maximum lesion diameter ≤ 2 cm, 2.1-3.0 cm and >3.0 cm, respectively (P < 0.001) and was strongly associated with perineural (P < 0.001; OR = 26.46, 95% CI = 5.62-124.52) and lymphatic invasion (P < 0.001; OR = 17.35, 95% CI = 4.44-67.91). Within 18-84 months, no recurrence or metastasis were observed in SLNM positive patients. False negative SLNB rate of 15.4% was recorded.

CONCLUSION

Cutaneous BSC is associated with early nodal metastatic potential. Tumor size >2 cm, lymphatic and perineural invasion are significant determinants for SLN micrometastasis. In the absence of palpable lymphadenopathy, wide resection and SLNB with long-term follow-up are highly recommended in these patients.

The Use of BEREP4 Immunohistochemistry Staining for Detection of Basal Cell Carcinoma

Basal Cell Carcinoma (BCC) is the most common type of malignant cancer found in the world today with a 3–10% increase in incidence each year. The American Cancer Society reported that 8 out of 10 patients with skin cancer are suffering from BCC with over 2 million new cases each year. BCC needs to be detected at the early stages to prevent local destruction causing disabilities to patients and increasing treatment costs. Furthermore, BCC patients who have undergone surgery are still at risk for recurrence, especially when the surgery performed fails to remove all the BCC cells, even when conventional histopathological testing after surgery has reported a surgically free margin. This review aims to evaluate studies on the use of BerEP4 immunohistochemistry staining on pathological sections of various types of BCC as well as its shortfalls. BerEP4 is a monoclonal antibody which detects specific epithelial-glycoprotein-adhesion-molecules (EpCAM) found on BCC cells. Various studies have shown that BerEP4 has a high sensitivity and specificity in detecting only BCC cells. The use of BerEP4 immunohistochemistry testing for the routine examination of cases of BCC is expected to be able to increase and improve early diagnosis as well as prevent recurrence after surgery.

Basosquamous Carcinoma: Controversy, Advances, and Future Directions

BACKGROUND

Basosquamous carcinoma is a rare cutaneous neoplasm that has caused considerable controversy as to its classification, pathogenesis, and management.

OBJECTIVE

To review and summarize current literature on the definition, pathogenesis, incidence, and management of basosquamous carcinoma.

MATERIALS AND METHODS

Through December 2015, an electronic search of the Pubmed database was performed using combinations of basosquamous carcinoma and metatypical basal cell carcinoma as search terms.

RESULTS

A selection of 39 publications including case reports and series, retrospective studies, and systematic reviews of the literature were included. Descriptions of the definition of basosquamous carcinoma, clinical behavior, histopathological characteristics, current treatment therapies, and future advances are summarized.

CONCLUSION

This systematic review provides a comprehensive overview of the current understanding of basosquamous carcinoma. Further study is required to elucidate the mechanisms driving the formation of this aggressive tumor.

Histopathologic pitfalls of Mohs micrographic surgery and a review of tumor histology

Mohs micrographic surgery is a specialized subset of staged surgical excisions with each subsequent stage being driven largely by the histologic findings of the previous stage. Therefore, it is imperative that histologic analysis is performed in an accurate manner. Frozen section and tissue flattening is a crucial step in Mohs surgery. Frozen sections introduce certain artifacts and these artifacts must be interpreted in the correct context. Basal and squamous cell carcinomas are the most common tumors encountered in Mohs micrographic surgery, and their histopathology is also associated with certain "pitfalls". Basal cell carcinoma should be distinguished from hair follicles, folliculocentric basaloid proliferations, poromas, nevus sebaceous, desmoplastic trichoepitheliomas, and spiradenomas, to name but a few histologic entities. Similarly, squamous cell carcinoma should be distinguished from hypertrophic actinic keratoses, pseudoepitheliomatous hyperplasia, sebaceous carcinoma, and microcystic adnexal carcinoma. In addition, there are numerous subtypes of basal cell and squamous carcinomas that the Mohs surgeon should be aware of due to differences in the biologic behavior of these tumors. This review presents a number of the common histologic pitfalls of Mohs micrographic surgery and a review of tumor histology.

Basosquamous carcinoma of the head and neck: clinical and histologic characteristics and their impact on disease progression

OBJECTIVES: Basosquamous carcinoma (BSC) is a rare tumor entity, and the most common onset is in the head and neck region (BSC-HN). The data on diagnosis, treatment, and especially risk assessment concerning disease course and outcome are deficient or inconsistent. This study aimed to evaluate risk factors for local relapse (LR) and lymph node metastasis (LNM) and their impact on progression-free survival (PFS). MATERIALS AND METHODS: In a retrospective monocentric study, patients with BSC-HN treated between 1999 and 2011 were analyzed regarding clinical and histologic characteristics. Prognostic parameters for LR, LNM, and PFS were evaluated. In total, 89 patients (55 male, 34 female, mean age of 71.8 years) with a mean follow-up time of 47.7 months (range 12-112) were included. RESULTS: LR occurred in four patients (4.5%), LNM occurred in five patients (5.6%). Patients with LNM had a significantly shorter PFS time (16.1 months) compared with patients without LNM (154.2 months; P < .001). Tumor depth and size (T classification), incomplete resection, localization at the ear, deep maximal vertical infiltration, muscle and vessel invasion all showed significant (P < .05) associations with LR, LNM, and shorter PFS time. BSC showed more histologic features of basal cell carcinoma (BCC), especially with regard to BerEP4 expression. CONCLUSION: While histology shows some typical characteristics of BCC, the biologic behavior and aggressiveness of BSC are similar to those of cutaneous squamous cell carcinoma. This is the first study to show that LR and, especially, LNM indicate a higher risk of an unfavorable outcome.

Relapsing advanced metatypical basal cell carcinomas (MTBCC) of the face: surgical modalities

Metatypical basal cell carcinoma (MTBCC) represents a high-risk type of cutaneous tumour. We report about three different patients with relapsing advanced large MTBCC: one of the scalp and two of the cheek region. Such patients required in most of the cases a complex surgical approach to achieve a stable and complete remission. In the first presented patient a combination of flaps and grafts has been performed. We describe tailored surgical approaches. By this contrivance it is possible to treat even elderly patients with exposed bone after complete excision effectively and safe. Interdisciplinary team work is for the benefit of these patients.

Metatypical Basal cell carcinomas: a successful surgical approach to two cases with different tumor locations

We present 2 rare cases of metatypical basal cell carcinoma - two 72-year-old male patients with ulcerative lesions localized either to the left forehead or the back. The biopsy revealed a metatypical basal cell carcinoma. The treatment consisted of a wide local elliptical excision with good cosmetic results. There was no sign of recurrence or metastasis during a 12 months follow-up period.Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) make up 95% of the most common types of cancer in the world - the non-melanoma skin cancer (NMSC). BCC is known for its potential to be locally invasive while SCC for its potential to metastasize in lymph nodes. The meta-typical basal cell carcinoma (MTBC) is a rare type of tumor which combines the clinical and histopathological features of both BCC and SCC with a 5% risk for the development of metastases. The gold standard for diagnosis lies in the histopathological verification of the lesional tissue. Clinical examinations alone are not enough.

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.

Epidemiology of basal cell carcinoma

Basal cell carcinoma is the most common malignant neoplasm in humans and its incidence has increased over the last decades. Its high frequency significantly burdens the health system, making the disease a public health issue. Despite the low mortality rates and the rare occurrence of metastases, the tumor may be locally invasive and relapse after treatment, causing significant morbidity. Exposure to ultraviolet radiation is the main environmental risk factor associated with its cause. However, other elements of risk are described, such as light skin phototypes, advanced age, family history of skin carcinoma, light eyes and blond hair, freckles in childhood and immunosuppression. Behavioral aspects such as occupational sun exposure, rural labor and sunburns at a young age also play a role. Between 30% and 75% of the sporadic cases are associated with patched hedgehog gene mutation, but other genetic changes are also described. The tumor is commonly found in concomitance with skin lesions related to chronic sun exposure, such as actinic keratoses, solar lentigines and facial telangiectasia. The prevention of basal cell carcinoma is based on the knowledge of risk factors, early diagnosis and treatment, as well as on the adoption of specific measures, particularly in susceptible populations. The authors present a review of the epidemiology of basal cell carcinoma.

Basosquamous carcinoma involving the anterior skull base: a neglected tumor treated using intraoperative navigation as a guide to achieve safe resection margins

Basosquamous carcinoma (BSC) or metatypical carcinoma is a rare and controversial form of basal cell carcinoma (BCC) that was first described by MacCormac in 1910. Numerous theories have been described in the literature regarding its origin but it is generally accepted as a variant of BCC that differentiates into squamous cell carcinoma (SCC). At present, it has an unsatisfactorily established phenotype but is considered to behave more like an SCC than a BCC. A reflection of this fact is its more aggressive nature with a significantly increased incidence of local and distant metastasis. It must be distinguished histologically from so-called "collision" tumors, which represent SCC and BCC arising as separate entities in the same area. We present a unique case of a neglected, large, and locally advanced case of BCC originating from the nose, but extending into the paranasal sinuses, orbit, and anterior skull base, that was treated with en bloc surgical resection using intraoperative navigation to assist in treatment planning and margin clearance.

Infundibular carcinoma of the skin: a distinct morphological and immunohistochemical entity

This report describes a new entity which has been defined as infundibular carcinoma (IC) of the skin. This new entity must be distinguished from other basaloid carcinomas arising from the epidermis, the hair follicles or from sweat duct and glandular elements. Specific criteria have been used to define ICs. These include the macroscopic and the microscopic site of the tumour as well as its histomorphological and immunohistochemical patterns. A brief review of benign and malignant tumours of the pilar unit and the differential diagnosis of IC is also provided.