Basosquamous carcinoma

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.

Basal cell carcinoma-not always the 'good guy': Case report of a life-threatening basosquamous carcinoma and review of the literature

Cutaneous basosquamous carcinoma is a variant of basal cell carcinoma that is characterized by histopathological features of both basal and squamous cell carcinoma. Due to its local invasiveness, high frequency of recurrence, and its metastatic potential, it is considered to be one of the most aggressive subtypes of basal cell carcinoma. We present the case of an 81-year-old male who was admitted to the hospital with incessant hemorrhage arising from a cutaneous tumor that later proved to be a basosquamous carcinoma. Due to the COVID-19 pandemic at the time, the patient did not seek medical attention as soon as the bleeding was observed, although he did present when the symptom increased in intensity and became incessant. To our knowledge, this is the first case report of a cutaneous basosquamous carcinoma that presents with a massive life-threatening hemorrhage tumor, thus endangering the patient's life. The clinical and histopathological features, the behavior and the treatment of cutaneous basosquamous carcinoma are further reviewed in this article.

Clinical and epidemiological analysis of basosquamous carcinoma: results of the multicenter study

Basosquamous carcinoma (BSC) is a rare non-melanoma skin cancer that shares the characteristic features of both basal and squamous cell carcinomas (BCC, SCC). Our research enables better characterization of BSC in comparison to high-risk subtypes of BCC and SCC. Paper includes a retrospective analysis of BSC cases regarding sex, age, number of tumors and anatomical distribution in comparison to BCC and SCC evaluating the differences and defining the implications. Histologically confirmed carcinomas recorded between 1999 and 2019 were studied. 181 diagnosed BSC cases were identified, making this study the largest cohorts of BSC patients reported worldwide. Most cases were reported on head and neck. Analysis of facial anatomic distribution shows that most commonly affected sites were the nose (43%) and the cheek (25%). The age at excision of metatypical BCC was higher than those of low-risk BCC (P < 0.05), however similar to high-risk BCC (P = 0.20). We revisited that the concept of BSC is the most similar to high-risk subtypes of BCC. Patients with diagnosed BSC have higher risk of second nonmelanoma skin cancer. Therefore, the frequency of follow-up examination should be adjusted to the individual risk of another skin cancer.

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.

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.

Is early detection of basal cell carcinoma worthwhile? Systematic review based on the WHO criteria for screening

The incidence of basal cell carcinoma (BCC) has risen three- to fourfold over the last 30 years and is expected to continue to increase with ageing of the population. Although BCC has a good prognosis, it causes significant morbidity and has an important impact on the public health budget due to direct treatment costs. Based on the existing evidence, a systematic evaluation of the World Health Organization criteria was performed to determine whether earlier detection of BCC could reduce morbidity and cost. BCC slowly increases in size, with a median increase in diameter of 0·5 mm over 10 weeks. There is an important delay in diagnosis ranging from 19 to 25 months. In several studies BCC size was the main determinant of treatment cost, surgical complexity, reconstruction technique and the specific surgical procedure performed, such as Mohs micrographic surgery or surgical excision. One study showed that size also seems to affect the cost per treatment for other nonsurgical options. The use of vismodegib, an inhibitor of the hedgehog pathway, is confined to locally advanced or metastatic BCC. Delays in diagnosis and appropriate treatment are the most important underlying causes in the occurrence of giant BCC and/or BCC with metastasis. Although the latter represent only a very small fraction of all BCCs, the majority of them are located in the facial region. The available data point to a slow increase in the size of BCCs over time. Size is one of the major determinants in choice of treatment and the associated cost, especially for facial BCC. Therefore we conclude that current data support early detection and adequate management of BCCs on the face.

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.

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.

Pink lesions

Dermoscopy (dermatoscopy or surface microscopy) is an ancillary dermatologic tool that in experienced hands can improve the accuracy of diagnosis of a variety of benign and malignant pigmented skin tumors. The early and more accurate diagnosis of nonpigmented, or pink, tumors can also be assisted by dermoscopy. This review focuses on the dermoscopic diagnosis of pink lesions, with emphasis on blood vessel morphology and pattern. A 3-step algorithm is presented, which facilitates the timely and more accurate diagnosis of pink tumors and subsequently guides the management for such lesions.

Dermoscopy of basosquamous carcinoma

BACKGROUND

Basosquamous carcinoma (BSC) is a rare and potentially aggressive tumour, characterized by clinical and pathological features of both basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). It is reported to have a nonspecific clinical presentation, which makes naked-eye diagnosis a challenge.

OBJECTIVES

To describe the dermoscopic patterns of BSC, which may facilitate early diagnosis and accurate management.

METHODS

This was a retrospective evaluation of clinical and dermoscopic images of histopathologically proven BSC, collected from skin cancer centres in Australia (Perth), Greece (Thessaloniki) and Italy (Naples, Reggio Emilia).

RESULTS

Twenty-two tumours were included in the study. Our analysis revealed that the dermoscopic pattern of BSC comprises BCC-related criteria, as well as features that are known to characterize invasive SCC. The most frequently detected criteria were: unfocused (peripheral) arborizing vessels (73%), keratin masses (73%), white structureless areas (73%), superficial scale (68%), ulceration or blood crusts (68%), white structures (64%), blue-grey blotches (59%) and blood spots in keratin masses (55%). Notably, all but one of the tumours exhibited at least one BCC-related plus one SCC-related dermoscopic feature.

CONCLUSIONS

BSC appears to have overlapping dermoscopic features of BCC and invasive SCC, and detection of at least one dermoscopic criterion of both BCC and SCC should raise suspicion for the tumour. Appreciation of the dermoscopic patterns of BSC might assist in the timely and accurate diagnosis and subsequent optimal management of this unusual and potentially metastatic skin tumour.

Basosquamous carcinoma: histopathological features

Basosquamous carcinoma (BSC) is a rare aggressive epithelial neoplasm with features of both basal cell carcinoma and squamous cell carcinoma, with a tendency toward local recurrence and a propensity for lymph node and distant metastases. The aim of the present study was to report the case of a 63-year-old Caucasian male with BSC in the auricular region.

Application of sentinel lymph node biopsy in cutaneous basosquamous carcinoma

Basosquamous carcinoma of the skin is a relatively rare cutaneous neoplasm that has significant metastatic potential and a metastatic rate greater than that of basal cell and squamous cell carcinoma. We describe the use of lymphatic mapping and sentinel lymph node biopsy in a 63-year-old man after identification of basosquamous carcinoma. Sentinel lymph node biopsy, which is a standard tool to detect regional lymphatic metastasis in cutaneous melanoma, has been rarely employed to detect lymphatic metastasis of basosquamous carcinoma. The approach was successful in detecting a regional lymphatic metastasis of two nodal basins with minor morbidity. Sentinel lymph node biopsy may be useful for certain high-risk lesions of basosquamous 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.

Basosquamous carcinoma

BACKGROUND

Basosquamous carcinoma is considered an aggressive type of basal cell carcinoma (BCC) with an increased risk of recurrence and metastases. This concept has been perpetuated in the literature in spite of confusing terminology, limited scientific data, and the contradictory surgical experiences of some observers.

METHODS

This is a narrative review based on a MEDLINE search of articles in English and a manual search of popular dermatology textbooks to define basosquamous carcinoma, its incidence, clinical behavior, and treatment of choice.

RESULTS

There are no specific clinical features to distinguish basosquamous carcinoma from other BCC types and the diagnosis is made only after biopsy. There are several histologic definitions of basosquamous carcinoma ranging from a characteristic combination of BCC and squamous cell carcinoma with or without a transition zone, to any BCC with evidence of keratinization. The authors confine the use of the term to an infiltrative growth BCC with areas of keratinization and/or intercellular bridge formation in the setting of a prototypic proliferative stromal reaction. The term "metatypical basal cell carcinoma" is considered a synonym but its use is discouraged for the reasons outlined. The reported incidence of basosquamous carcinoma ranges from 1.2% to 2.7%. Published recurrence rates are 12% to 51% for surgical excision and 4% for Mohs micrographic surgery. The incidence of metastasis is at least 5%. The aggressive biological behavior and clinical course distinguish basosquamous carcinoma from other forms of BCC.

LIMITATIONS

This study is a literature review, contains a limited number of patients, and is mostly retrospective studies.

CONCLUSION

The terminology surrounding basosquamous carcinoma is confusing and there is a need for more uniform language. Based on our review and personal experience, we propose a more precise and specific definition. Data regarding the incidence, recurrence, and metastasis rates of basosquamous carcinoma are based mostly on retrospective series with a limited number of cases. We conclude that although the incidence of basosquamous carcinoma is unknown, there is a literature precedent suggesting more aggressive biological behavior. We believe that complete surgical excision is the preferred approach, and that basosquamous carcinoma is an ideal candidate lesion for Mohs micrographic surgery.

Metatypical basal cell carcinoma: a clinical review

Background

Metatypical cell carcinoma can be considered as a new entity of skin cancer, being an intermediate typology between basal cell carcinomas and squamous cell carcinomas. The behaviour of the metatypical cell carcinoma lies between these two varieties of skin cancer. It is difficult to perform a differential diagnosis based on morphological and clinical features – therefore it is only possible by accurate histology.

Methods

The authors have retrospectively analysed clinical records of 240 patients who were affected by metatypical skin cancer and who were treated by surgery, radiotherapy and chemotherapy.

Results

MTC affected more males than females (62.5% vs 37.5%) than males. The most affected site was the cervicofacial area, 71.7%; then the trunk, 10%; the limbs, 9.6%; the scalp 3.7%; and other regions 5%. A recurrence occurred in 24 cases (10%), mainly in head and neck area.

Conclusion

In this manuscript, the authors have emphasised the importance of conducting a differential diagnosis, and the importance of the specific treatment for metatypical skin cancer, even though more clinical studies and long-term follow-ups are required before establishing specific guidelines.

[Cutaneous basosquamous cell carcinoma]

BACKGROUND

Basosquamous carcinoma (BSC) is a rare malignancy with specific histopathological features of both basal cell (BCC) and squamous cell carcinoma (SCC). Therefore, the histological diagnosis is challenging. Due to its low incidence there is no consensus on the surgical management of BSC.

PATIENTS AND METHODS

We describe the (immunohistological) diagnostic and therapeutic aspects of nine cases (8 male symbol : 1 female symbol, on average 68.6 years of age (range: 47-81)) of BSC. Of these, seven were located on the pinna, one on the forehead and zygomatic region and one in the retroauricular region.

RESULTS

Immunochemical staining for epithelial membrane antigen was negative (apart from the typical areas of epithelial pearl formation) and BerEP4 was positive in all cases. Therapy consisted of partial removal of the pinna in four, and total removal in three cases. One patient was treated by partial removal of the auricle with superficial parotidectomy and ipsilateral neck dissection. In the case of the carcinoma on the forehead, a local excision was performed. The median follow-up was 45 months. One patient had a local recurrence.

CONCLUSIONS

The histological diagnosis of BSC is confirmed by the use of EMA and BerEP4 immunohistological staining. Clinically, BSC is a rare, aggressive skin tumor. Despite the histological similarity to basal cell carcinoma, BSC has an imminent risk of metastasizing. Hence, therapy should be similar to that for SCC, taking into consideration the age and general state of the usually elderly patient.

Periocular metatypical cell carcinoma: clinicopathologic correlation, management, and follow-up in 35 patients

BACKGROUND

To present the clinical characteristics and treatment outcomes in a relatively large series of patients with periocular metatypical cell carcinoma.

METHODS

This is a retrospective study of 35 patients with periocular metatypical cell carcinoma, who were seen between January 2000 and December 2004 in Izmir Ataturk Research and Training Hospital, Turkey. The patients were histologically confirmed metatypical cell carcinoma with radiologic evidence of periocular region. The main outcome measures were patients' demographics, duration of tumour, clinical presentation, tumour site, treatment modalities, recurrence rate and tumour-related exenteration. Statistical comparisons between the nonrecurring group and recurring group were completed using the Cox regression analysis and the log rank test. Significance was determined for all statistical tests as pé 0.05.

RESULTS

The median age of patients at time of diagnosis was 61 years. The most common site for metatypical cell carcinoma was medial canthus and lower eyelid region. The median follow-up for all patients was 18 months. The average length of time until recurrence was 13 months. Five of the 35 patients received adjuvant therapy to the primary tumour site after excision. Signs suggestive of orbital involvement included bone fixation of the mass, limitation of ocular motility and globe displacement. The early lack of diagnostic criteria for metatypical cell carcinoma created considerable debate and confusion regarding its diagnosis. We believe that once this diagnosis is made, the treatment modality should be individualized and chosen with consideration of the extent of orbital involvement, visual function, and the patient's general health.

Recurrent basosquamous cell carcinoma of the vulva

BACKGROUND

Basosquamous cell carcinoma (BSC) of the vulva is a rare entity with interesting prognostic and therapeutic implications. Currently, there is no definitive treatment due to its low incidence.

CASE

A case of recurrent BSC of the vulva treated with unilateral radical vulvectomy and unilateral lymph node dissection is reported.

CONCLUSION

BSC is a rare disorder of the vulva. The metastatic potential of this tumor is not fully understood, but likely is intermediate between squamous cell carcinoma and basal cell carcinoma. Local recurrence is common and close follow-up is warranted.

Basosquamous carcinoma—an under-recognized, high-risk cutaneous neoplasm: Case study and review of the literature

Basosquamous carcinoma of the skin is a relatively rare cutaneous neoplasm that has been shown to have significant metastatic potential. Histopathologists debate whether these lesions arise de novo or differentiate from pre-existing basal cell carcinomas. We present a case in which a longstanding lesion initially diagnosed as basal cell carcinoma was later found to have basosquamous histology and regional metastases. Review of the literature reveals a metastatic rate greater than that of basal cell and squamous cell carcinoma, and identifies several important characteristics that impact prognosis after surgical resection. For physicians treating carcinomas of the skin, it is important to understand the natural history and proper treatment of this aggressive neoplasm.

Squamous cell carcinoma of the skin: dual differentiations to rare basosquamous and spindle cell variants

Basosquamous carcinoma (BSC) is defined as a tumor containing the areas of both basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) with a transition zone linking the two. Spindle cell squamous carcinoma (SCSC) may have a variable component of conventional SCC and spindle cells. We present a case of an 89-year-old woman with an eruption on the scalp for several decades. Grossly, the lesion measured 8.5 x 6.0 x 1.8 cm and consisted of a gray-white and focally black tumor. Microscopically, a non-ulcerated upper part of the tumor consisted of large polygonal squamoid cells with occasional keratinization (SCC), trabecular growth of basaloid cells with peripheral palisading (BCC), and an area in which both the components were intermingled. The rest of the tumor was a myxoid area with elongated fusiform spindle cells, which appeared to arise from conventional SCC. Immunohistochemically, the tumor cells in the SCSC (both conventional and spindle cell) area co-expressed CAM5.2, and vimentin. Ber-EP4 was positive in the BCC area with the transition zone of SCC and BCC showing diminished staining. Epithelial membrane antigen was focally positive in the conventional SCC area. To our knowledge, this is the first case report of SCC of the skin that has dual differentiations to BSC and SCSC.

Surgical Margins in the Treatment of Nonmelanoma Skin Cancer and Mohs Micrographic Surgery

Traditional surgical treatment of nonmelanoma skin cancer includes excision with subsequent evaluation of surgical margins, either via frozen sections intraoperatively or after excision and closure. Accurate communication between surgeon and pathologist regarding the meaning of surgical margins should be confirmed. Recurrences of tumor growth may in part be attributed to asymmetrical tumor growth patterns with extension of tumor in an unanticipated direction. Mohs micrographic surgery is an outpatient procedure that maximizes surgical margin evaluation while minimizing the amount of tissue that must be excised. This article will discuss the concept of surgical margins in excisions of nonmelanoma skin cancer and the role of Mohs micrographic surgery.

Mohs micrographic surgery and the otolaryngologist

OBJECTIVE

The purpose of this study was to provide an update and overview of the current indications for Mohs micrographic surgery (MMS) for cutaneous and upper aerodigestive tract malignancies.

STUDY DESIGN

Literature review.

METHODS

A comprehensive review of the literature from 1971 to present was completed by using the Medline data base. In addition, interviews were obtained with several otolaryngologists who had used the technique.

RESULTS

MMS offers a superior alternative to standard excision in a variety of cutaneous malignancies. Overall, for the skin cancers likely to be encountered by the otolaryngologist, there is significant evidence that MMS offers increased rates of cure as well as tissue conservation. The role of MMS in upper aerodigestive tract malignancies continues to evolve and multiple issues must be addressed before its general application.

CONCLUSIONS

When confronted with a difficult cutaneous malignancy, the otolaryngologist should consider MMS to optimize treatment results.