Micronodular basal cell carcinoma. A deceptive histologic subtype with frequent clinically undetected tumor extension

Accuracy of Optical Coherence Tomography for Subtyping Basal Cell Carcinoma: Using Histopathology of Biopsy and Entire Lesion as Reference Standard

Abstract is missing (Short communication)

Risk Factors for Complicated Mohs Surgery in the South Sweden Mohs Cohort

BACKGROUND

Mohs micrographic surgery (MMS) is a precise, tissue-sparing surgical technique that offers superior cure rates compared to traditional surgical excision. However, the degree of difficulty of MMS depends on many variables and, consequently, the number of surgical stages required for each case is quite unpredictable.

OBJECTIVES

To identify risk factors for complicated MMS, defined as MMS requiring ≥3 stages.

METHODS

In a cohort study design, data was prospectively collected from 612 patients that underwent MMS for basal cell carcinoma (BCC) at the Department of Dermatology, Skåne University Hospital, Lund, between 2009 and 2020. Univariate and multivariate logistic regression were used to estimate risk of MMS requiring ≥3 stages. Due to risk of multicollinearity between recurrent or incompletely excised BCC and previous treatments, a partially and a fully adjusted multivariate logistic regression model were constructed.

RESULTS

In fully adjusted multivariate analyses, age (odds ratio (OR) 1.02; confidence interval (CI) 95% 1.00-1.04), previous cryotherapy (OR 2.3; CI 95% 1.1-4.8) and >1 previous surgery (OR 3.4; CI 95% 1.5-7.7) were significantly associated with risk of complicated MMS. Recurrent BCC was associated with risk of complicated MMS in partially adjusted multivariate analyses, but not in the fully adjusted analyses. In this highly selected cohort, histopathological subtype and tumour localisation were not associated with risk of complicated MMS.

CONCLUSIONS

Older age and tumours previously treated with cryotherapy or multiple prior surgeries increased risk of MMS requiring ≥3 stages. Whether recurrent BCC is an independent risk factor for complicated MMS needs further evaluation. Knowledge of these risk factors may ameliorate planning of Mohs surgeries.

Long-term efficacy and safety of ustekinumab for moderate-to-severe psoriasis: A 9-year real-life experience from a tertiary referral center in Turkey

There is a paucity of data on long-term (≥5-year) outcomes of ustekinumab therapy for psoriasis in real-life clinical practice. This observational, retrospective study aimed to evaluate the long-term efficacy and safety profile of ustekinumab in 52 adult patients with moderate-to-severe chronic plaque psoriasis who were treated with ustekinumab for at least 28 weeks and a maximum of 105 months in our tertiary referral center in Turkey, between 2010 and 2019. Response to therapy was assessed using Psoriasis Area and Severity Index (PASI). Logistic regression analysis was performed to determine significant associations (p-value <0.05) with response to treatment. The PASI50, PASI75, PASI90, and PASI100 response rates were 97.8%, 88.9%, 53.3%, and 35.5%, respectively, at year 1 and 100%, 80.0%, 60.0%, and 40.0%, respectively, at year 5. Non-obesity was independently associated with PASI90 response at year 2 (p = 0.043), while biologic-naivety was independently associated with PASI90 responses at year 2 (p = 0.047) and year 3 (p = 0.021). An absolute PASI score of ≤3 was achieved by 82.2% and 80.0% of the patients at year 1 and year 5, respectively. Nine patients received adjuvant therapy and nine underwent ustekinumab dose escalation. These strategies were effective for recapturing clinical response in most patients. Ustekinumab was generally well-tolerated with no dose-related and cumulative toxicity, or drug interaction over a mean of 33.5 ± 21.1 months. The main reasons for discontinuation were secondary failure and loss to follow-up. Our 9-year real-life clinical experience demonstrates that ustekinumab is an efficacious and safe treatment option for long-term therapy of moderate-to-severe plaque psoriasis.

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.

Indication guidelines for Mohs micrographic surgery in skin tumors

Mohs micrographic surgery is a technique used to excise skin tumors based on comprehensive surgical mapping, in which the surgeon removes the tumor, followed by a complete histological evaluation of the tumor's margins. The correlation of the presence of a tumor in histological examinations and its precise location on the surgical map result in a complete removal of the tumor with maximum normal tissue preservation. The present article seeks to provide general practitioners and healthcare specialists with guidelines regarding recommendations for Mohs micrographic surgery to treat skin tumors, based on the most reliable evidence available in medical literature on the subject. This bibliographic review of scientific articles in this line of research was conducted based on data collected from MEDLINE/PubMed. The search strategy used in this study was based on structured questions in the Patient, Intervention, Control, and Outcome (PICO) format. MeSH terms were used as descriptors. The indications of this technique are related to recurrence, histology, size, definition of tumor margins, and location of tumors. These guidelines attempt to establish the indications of Mohs surgery for different types of skin tumors.

[Basal cell carcinoma and rare form variants]

Basal cell carcinomas are the most common primary cutaneous malignant neoplasms. The diagnosis of basal cell carcinoma represents a common and routine task for pathologists and dermatopathologists. The aim of this review is the clinical and histopathological presentation of the most common subtypes of basal cell carcinoma. Furthermore, the rare variants of basal cell carcinoma and their differential diagnoses are also discussed.

Cutaneous malignancies: melanoma and nonmelanoma types

This article reviews melanoma and nonmelanoma cutaneous malignancies.

The use of high-frequency ultrasound in the evaluation of superficial and nodular basal cell carcinomas

BACKGROUND

Frequencies of 20 MHz may be appropriate to visualize basal cell carcinomas (BCCs) including their tumor thickness and margins. Histologic comparisons to sonographic images are related at all levels of the epidermis and corium.

OBJECTIVE

The objective was to evaluate whether high-frequency ultrasound (HFUS) proved to be an inexpensive and noninvasive modality to adequately delineate tumor margins under favorable circumstances.

MATERIALS AND METHODS

Fifty superficial and nodular BCCs of various locations were scanned using a 20-MHz ultrasound device. Tumors were delineated, excised with 4-mm surgical margins, and sent for histologic clearance. Morpheaform, recurrent BCCs, BCCs in areas difficult to scan, and BCCs with specific properties were excluded from this study. RESULTS Clinical and ultrasonic measurements correlated well in terms of width, depth, and length (p<.0005). Of 50 BCCs, 45 were clear after margin assessment with HFUS. Five BCCs depicted extension past 4-mm surgical margins and returned with positive margins.

CONCLUSION

HFUS delineated tumor margins adequately, and it appeared to depict subclinical extension past 4 mm on less aggressive BCC variants. It could be warranted if clinical or histologic diagnosis is uncertain. The strong association between clinical and ultrasonic measurements initiates more successful forms of therapy, risk-stratifies specific subgroups of patients, and prevents overall morbidity.

Surgical treatment of basal cell carcinomas using standard postoperative histological assessment

SUMMARY Surgical treatment of basal cell carcinomas using postoperative histological assessment is routinely practised in Australia. The efficacy of the procedure depends on key decisions made by the surgeon. The first is case selection that requires an understanding of the limitations of the procedure. The tumour border is then identified and a margin added. The margin selected should achieve the desired balance between incomplete excision rate and mean tissue sacrifice. There is an inverse relationship between these parameters; achieving a 5% incomplete excision rate requires a mean tissue sacrifice of over 4 mm. Factors affecting margin selection are discussed, unfortunately none allows a dramatic reduction in mean tissue sacrifice. The final decision involves interpreting and acting on the histological examination of the excised specimen. Tumour recurrence is rare (less than 2% at 5 years) if the tumour is clear of the surgical margin. The visualized histological margin required to ensure complete excision varies with histological technique and tumour properties. Routine reporting of histological margin in millimetres or horizontal sectioning is recommended. Tumour recurrence averages 38% when the histological margin is involved. The merits of careful clinical follow up of incompletely excised tumours or immediate re-excision are discussed.

Histological evolution of recurrent basal cell carcinoma and therapeutic implications for incompletely excised lesions

BACKGROUND

It has been proposed that the management of incompletely excised recurrent basal cell carcinomas (BCCs) should depend on their histological appearance, and that nonaggressive recurrent BCCs may not require re-excision.

OBJECTIVES

To determine the histological evolution of recurrent BCCs.

METHODS

In a 14-year retrospective study analysing histological sections of recurrent BCCs, 390 specimens from 191 patients were blindly classified by three physicians into aggressive and nonaggressive types according to Sexton's classification. Initial histological sections were available for 33 of the recurrent BCCs. Descriptive analysis was performed.

RESULTS

Eight of 33 (24%) recurrent BCCs became histologically more aggressive. Four of 20 (20%) originally nonaggressive BCCs became aggressive during recurrence and four of 13 (31%) originally aggressive BCCs showed a more aggressive component during recurrence. These incompletely excised aggressive BCCs were sited in periorbital and perinasal areas and on the cheek, and were re-excised.

CONCLUSIONS

Management of incompletely excised nonaggressive BCCs (nodular or superficial types) is still a matter of debate. Previously reported studies have shown recurrence in < 10% of nonaggressive incompletely excised BCCs. Our study showed that rare recurrences of these initially nonaggressive BCCs showed an aggressive component in 20% of cases. These results suggest that initially nonaggressive incompletely excised BCCs do not require re-excision except if they are located in sites with a poor prognosis.

Basal cell carcinoma: a dermatopathological and molecular biological update

The ideal classification of basal cell carcinoma (BCC) should be able to identify subtypes which correlate with clinical behaviour and treatment requirements. Unfortunately, however, such a classification has yet to be defined. In the interim, the currently most favoured classification is one based predominantly on histological growth pattern. This classification contributes to the useful concept of low- and high-risk histological subtypes of BCC. The latter are characterized by an increased probability of subclinical extension and/or incomplete excision and/or aggressive local invasive behaviour and/or local recurrence. The Royal College of Pathologists has published a minimum dataset for the histopathological reporting of BCC and this has been written to be compatible with the British Association of Dermatologists' management guidelines. Growth patterns to be reported include nodular, superficial, infiltrative/morphoeic and micronodular types, together with differentiation when of severely atypical or malignant squamous type (basosquamous carcinoma). Deep and peripheral excision margins will be reported to be either involved or clear. The latter will include a comment of a clearance of less than 1 mm for close margins and a measured distance in whole millimetres for other excisions. Clinical assessment and histology remain the 'gold standard' for evaluating BCC and cancers in general. However, in the postgenomic era emphasis is changing from the gathering and archiving of genomic data to its analysis and use in guiding clinical practice. In this context, a current goal is to define cancer phenotype in terms of molecular abnormalities and use this as a new gold standard. One way to assess whether this goal is being achieved for BCC is to determine whether our knowledge of its molecular pathology has any relevance to the minimum dataset for histological reporting. Knowledge of BCC molecular pathology has been fuelled by the recent discovery that deregulation of the Hedgehog (Hh) signalling pathway, a key player in embryonic patterning, appears to be fundamental to tumour growth. But despite accrual of a large amount of data concerning Hh pathway molecular alterations in neoplasia, little is known about the functional consequences of these changes in BCC, how they lead to tumour development, or how they relate to non-Hh pathway alterations such as TP53 mutation. Recent work suggests that the cellular localization of beta-catenin gives a degree of credence to the growth pattern classification of BCC. Furthermore, it is possible that beta-catenin may have a pathogenetic role in the invasive behaviour of BCC. This review draws on current evidence to discuss these issues and assess whether they are relevant to the minimum dataset.

A correlation of alpha-smooth muscle actin and invasion in micronodular basal cell carcinoma

BACKGROUND

Actin is largely responsible for cell motility and is only sparsely found in normal epithelial cells. An altered expression of actin in some malignancies may facilitate aggressive invasion. Micronodular basal cell carcinoma (BCC) has been shown to require more surgical stages, wider tissue margins, and deeper defects for extirpation during Mohs micrographic surgery relative to nodular BCC.

OBJECTIVE

To provide preliminary data regarding a possible correlation between alpha-smooth muscle actin (alpha-SMA) expression within the cells or stroma of micronodular BCC and aggressive invasion. In addition, the incidence of alpha-SMA expression in micronodular, morpheaform, and nodular BCC is evaluated.

METHODS

Nine micronodular basal cell carcinomas (7 primary, 2 recurrent) were evaluated for neural invasion, depth of tissue invasion, and alpha smooth muscle actin antibodies. The presence of alpha-smooth muscle actin antibodies was assessed using immunoperoxidase staining and compared with 13 morpheaform (13 primary, 0 recurrent) and 12 nodular (12 primary, 0 recurrent).

RESULTS

Six of the nine micronodular (67%), eight of the 13 morpheaform (62%), and 0 of the 12 nodular (0%) BCCs stained positive for alpha-SMA. Of the six micronodular BCCs that stained positive for alpha-SMA, three invaded the fascia or muscle and three displayed neural invasion. In contrast, of the three micronodular BCCs that stained negative for alpha-SMA, none invaded the fascia or muscle and only one exhibited neural invasion.

CONCLUSION

Actin was present in 66% of micronodular, 62% of morpheaform, and 0% of nodular BCC. The presence of actin in micronodular BCC may be a marker for aggressive invasion.

Factors influencing the linear depth of invasion of primary basal cell carcinoma

BACKGROUND

Predicting subclinical growth of basal cell carcinoma (BCC) is important for clinicians to determine adequate surgical margins. However, few attempts to predict the depth of invasion of BCC prior to surgery have been done.

OBJECTIVE

To identify the factors significantly influencing the depth of invasion of primary BCC.

METHODS

In 235 primary BCCs treated with surgical excision, maximum vertical diameter, designated as "invasion index," from the surrounding skin surface to the bottom of the tumor was measured. Multiple linear regression analysis was used to identify the factors significantly influencing the invasion index. Seven variables including age, sex, duration, anatomic location, tumor horizontal diameter, histologic subtypes, and ulceration were entered into the model.

RESULTS

Among seven variables, male sex (P = 0.0003), larger tumor diameter (P = 0.0011), and histologic subtypes including infiltrative, morpheic, and micronodular subtypes (P = 0.0019) had significant strength of influence for the invasion index.

CONCLUSION

The three predictive factors positively related to the linear depth of invasion in this study are important, but not sufficient, considerations at planning of surgery and for postoperative follow-up of BCC.

Why classify basal cell carcinomas?

Basal cell carcinoma of the skin is the commonest form of cancer in the white population. A simple pathological classification is presented and recommended for general use to aid clinicians in their management of cases. Basal cell carcinoma can be classified as nodular, infiltrative, superficial apparently multifocal and mixed in terms of the histological growth pattern. These patterns can be related to the likelihood of complete excision and, if excision is incomplete, to the frequency of recurrence.