Cutaneous squamous cell carcinomas of the lower extremity: a distinct subset of squamous cell carcinomas

Cognitive bias in pathology, as exemplified in dermatopathology

Cognitive bias refers to human thinking patterns, as well as pitfalls, that are reproducible. Importantly, cognitive bias is not intentionally discriminatory and is necessary to properly interpret the world around us, including microscopic slides. Thus, it is a useful exercise to examine cognitive bias in pathology, as exemplified in dermatopathology.

Skeletal Mets From Squamous Cell Carcinoma of the Lower Limb: A Case Report

Squamous cell carcinoma (SCC) is the second most common non-melanoma skin cancer worldwide and one of the most capable of metastasis. The bone is a common metastatic site of cancers, which is a major cause of morbidity, with an estimated 350,000 people dying yearly from bone metastases. However, bone metastasis from an SCC in the lower limb is rarely reported in the literature and the role of systemic chemotherapy is not well established. We report a case of a 72-year-old gentleman with an SCC metastasis of the bone. This patient received six cycles of platinum-based chemotherapy with no surgical or radiation intervention.

KLF9 (Kruppel Like Factor 9) induced PFKFB3 (6-Phosphofructo-2-Kinase/Fructose-2, 6-Biphosphatase 3) downregulation inhibits the proliferation, metastasis and aerobic glycolysis of cutaneous squamous cell carcinoma cells

Cutaneous squamous cell carcinoma (CSCC) is the second most common skin cancer in humans with increasing incidence. In this paper, we focused on the effects of krueppel-like factor 9 (KLF9) on the progression of CSCC cells by binding to PFKFB3. mRNA and protein expressions of KLF9 and PFKFB3 in human HaCaT and CSCC cells were, respectively, examined by RT-qPCR analysis and Western blot. The viability, proliferation, invasion and migration of A431 cells after transfection were analyzed with MTT, clone formation, transwell and wound healing assays. The levels of glucose, lactic acid and ATP in transfected A431 cells were detected by their commercial kits. Ki-67 expression in transfected A431 cells was determined using immunofluorescence analysis and in tumor tissues was analyzed by immunohistochemistry. The levels of migration, EMT and aerobic glycolysis-related proteins were tested with Western blot. The combination of KLF9 and PFKFB3 was confirmed by dual-luciferase reporter assay and ChIP. As a result, PFKFB3 expression was elevated in CSCC cells compared with HaCaT. Knockdown of PFKFB3 restrained the proliferation, metastasis, and aerobic glycolysis of CSCC cells. In addition, KLF9 could bind to PFKFB3. Downregulation of KLF9 crippled the inhibitory effect of knockdown of PFKFB3 on the proliferation, metastasis, and aerobic glycolysis of CSCC cells. In conclusion, PFKFB3 was transcriptionally regulated by KLF9, and PFKFB3 silencing inhibits the proliferation, metastasis, and aerobic glycolysis of cutaneous squamous cell carcinoma cells.

Cryotherapy-Enhanced Chemowrap Treatment of Squamous Cell Carcinoma: A Case Series

An estimated 20% of all malignant cutaneous neoplasms are diagnosed as squamous cell carcinoma (SCC). Chemotherapeutic wraps, or chemowraps, consist of application of topical 5-fluorouracil (5-FU) 5% cream along with occlusive zinc oxide and a compressive bandage (e.g., Unna boot). This treatment modality is often used as a less invasive option compared to surgery, especially in the presence of numerous SCCs. Cryotherapy, the use of liquid nitrogen gas, can be utilized to obliterate pre-malignant and malignant skin lesions. In this report, we present four cases in which females between the ages of 65 and 80 with multiple lower extremity SCCs were treated with cryotherapy prior to each chemowrap application, resulting in favorable clinical tumor improvement. Our observations indicate that cryotherapy may enhance the effectiveness of chemowrap treatment when used before each application. To our knowledge, the use of cryotherapy to synergistically enhance the efficacy of chemowraps has not yet been reported. We hypothesize that cryotherapy induces edema and first strips the outer, hyperkeratotic layers of skin, which facilitates deeper penetration of the 5-FU cream from chemowraps. Chemowraps may also relieve the pain associated with cryotherapy. Therefore, dual cryotherapy and chemowrap treatment may be considered to maximize skin penetration, thus minimizing the extent of surgical intervention in patients with a significant number of SCC lesions.

Sex-based differences in the anatomic distribution of cutaneous squamous cell carcinoma

Background

Cutaneous squamous cell carcinoma (cSCC) is the second most common malignancy in the United States, and its incidence is increasing. Ultraviolet radiation is the main environmental risk factor for cSCCs; thus, they tend to arise on sun-exposed skin. Most publications cite the head and neck as the predominant location for cSCCs, but these papers do not account for the differential anatomic predication of cSCCs by sex. No prior studies have examined the differential distribution of cSCCs by sex, particularly invasive cSCCs that have the potential for recurrence and metastasis.

Objective

We examined the association between cSCC tumor features, including anatomic site and invasiveness, by key patient features, including age and sex.

Methods

Using an institutional cSCC registry, we identified 618 non-Hispanic white patients diagnosed with 2,111 histologically-confirmed cSCCs between 2000–2016.

Results

We found differential anatomic distributions of cSCC by patient sex. Men were more likely to have cSCCs arise on the head and neck (51.7%), whereas women were more likely to have cSCCs develop on the lower extremity (41.2%). Stratification by dichotomized age (younger [<65 years] vs. older [≥65 years]) revealed that nearly half of invasive cSCCs (47.7%) among older women arose on the lower extremities, whereas approximately half of the invasive cSCCs (52.4%) arose on the head and neck among older men.

Conclusion

Lower extremities can be easily overlooked, particularly when practitioners perform waist-up-only skin examinations in time-limited settings. Understanding the anatomic predilection for invasive cSCCs by patient characteristics, including our findings, which suggest that the lower extremities are an important anatomic site for invasive cSCCs among women, can help further inform skin cancer screening and prevention efforts.

The management of malignant lower limb ulcers: clinical considerations

Lower limb malignant ulcers are an uncommon finding, making diagnosis complex and their management costly. Yet, despite this, the increase in skin cancers over the past 30 years means that clinicians require an awareness and understanding of their existence, particularly in the primary care setting. Familiarity with common aetiologies and presentations is vital for prompt recognition, diagnosis and referral of wounds suspicious for malignancy. Lower limb malignant wounds often develop insidiously, with a wide variation in clinical presentation that overlaps between entities. Therefore, a fundamental algorithm for approaching lower limb ulcers that raise suspicion of malignancy should be possessed by all clinicians. This article reviews the clinical features of malignant wounds that should alert clinicians to the need for further evaluation, such as atypical location and appearance. The authors also highlight the various diagnostic and therapeutic modalities available and review current clinical guidelines for the referral and follow-up of suspicious lesions.

Prognostic Significance of RAS Mutations and P53 Expression in Cutaneous Squamous Cell Carcinomas

TP53 is considered the most commonly-altered gene in cutaneous squamous cell carcinoma (cSCC). Conversely, RAS mutations have been reported in a low percentage of cSCC. The objective of our study was to evaluate the frequency of p53 expression and RAS mutations in cSCC and correlate them with clinicopathological features and patient outcome. We performed immunohistochemistry for p53 and genetic profiling for RAS mutations in a retrospective series of cSCC. The predictive value of p53 expression, RAS mutations, and clinicopathological parameters was assessed using logistic regression models. The overall frequency of RAS mutations was 9.3% (15/162), and 82.1% of the cases (133/162) had p53 overexpression. RAS mutations rate was 3.2% (1/31) of in situ cSCCs and 10.7% (14/131) of invasive cSCCs. RAS mutations were more frequently associated with an infiltrative than an expansive pattern of invasion (p = 0.046). p53 overexpression was a predictor of recurrence in the univariate analysis. Our results indicate that RAS mutations associate with features of local aggressiveness. Larger studies with more recurrent and metastatic cSCCs are necessary to further address the prognostic significance of p53 overexpression in patients’ risk stratification.

Antitumor Effect of Albendazole on Cutaneous Squamous Cell Carcinoma (SCC) Cells

Drug repurposing and/or repositioning is an alternative method to develop new treatment for certain diseases. Albendazole was originally developed as an anthelmintic medication, and it has been used to treat a variety of parasitic infestations. In this study, we investigated the antitumor effect of albendazole and putative action mechanism. Results showed that albendazole dramatically decreased the cell viability of SCC cell lines (SCC12 and SCC13 cells). Albendazole increased apoptosis-related signals, including cleaved caspase-3 and PARP-1 in a dose-dependent fashion. The mechanistic study showed that albendazole induced endoplasmic reticulum (ER) stress, evidenced by increase of CHOP, ATF-4, caspase-4, and caspase-12. Pretreatment with ER stress inhibitor 4-PBA attenuated albendazole-induced apoptosis of SCC cells. In addition, albendazole decreased the colony-forming ability of SCC cells, together with inhibition of Wnt/β-catenin signaling. These results indicate that albendazole shows an antitumor effect via regulation of ER stress and cancer stemness, suggesting that albendazole could be repositioned for cutaneous SCC treatment.

Cutaneous immunohistochemical staining pattern of p53β isoforms

p53 is considered the guardian of the genome and as such has numerous functions. The TP53 gene is the most commonly mutated gene in cancer, and yet the exact biological significance of such mutations remains unclear. There are at least 12 different isoforms of p53, and the complexity of the p53 pathway may be in part related to these isoforms. Prior research has often not teased out what isoforms of p53 are being studied, and there is evidence in the literature that p53 isoforms are expressed differently. In this paper, we document the staining pattern of p53β isoforms in the skin and correlate it with mutational status in a subgroup of squamous proliferations of the skin. p53β isoforms are present in the cytoplasm of the differentiated layer of the epidermis and hair follicles (granular layer, infundibular and isthmus-catagen). p53β isoforms are diffusely expressed within the cytoplasm of well-differentiated squamous tumours with tetramerisation (C-terminal) domain mutations in TP53 Our results lend support to p53β isoforms being a marker of differentiation in keratinocytes.

Effect of Postoperative Dressing on Excisions Performed on the Leg: A Comparison Between Zinc Oxide Compression Dressings Versus Standard Wound Care

BACKGROUND

Wound healing on the legs may be complicated by delayed healing and other postoperative problems. Two potential postoperative wound care regimens for sutured excisions on the legs include a standard pressure dressing and zinc oxide compression dressings. Limited data exist comparing the efficacy of these 2 options.

OBJECTIVE

To compare outcomes of standard postoperative wound care dressing versus postoperative use of a zinc oxide compression dressings for sutured repairs on the legs.

METHODS

In this retrospective cohort study, healing time and complication rate of 44 patients treated with standard dressing and 36 patients treated with zinc oxide compression dressings were compared.

RESULTS

At 19 days, 91.7% of patients receiving zinc oxide dressing were fully healed, whereas only 65.9% of patients receiving standard wound care were healed. Complications were noted in 6 of the patients receiving standard dressing (13.6%); no complications occurred in the zinc oxide dressing group.

CONCLUSION

Zinc oxide compression dressings were a practical option for postoperative wound care, with decreased incidence of delayed wound healing, and fewer complications versus standard postoperative wound dressing.

Histopathologic features of multiple cutaneous squamous cell carcinomas of the lower extremity

Recent studies suggest cutaneous squamous cell carcinomas (SCCs) of the leg, particularly those occurring multiply in sun exposed skin of nonimmunosuppressed women, are a distinct clinical subtype. There are few reports of the histopathologic features of this subtype. A retrospective chart review of 4 patients with multiple SCCs on the leg was performed and a total of 35 biopsies from the legs examined. Histopathologically, the tumors lacked adjacent actinic keratosis (AK) and often had adjacent basaloid retiform proliferations. Most lesions (all but one) were well differentiated and about 40% could be classified histopathologically as keratoacanthoma. Perineural invasion was absent in all but one case. Using the American Joint Committee on Cancer (AJCC) staging criteria for SCC, 21 tumors were Stage I, and 9 Stage II. During 7-10 years of follow-up, no recurrence or metastasis occurred. Patients with multiple SCCs on the lower extremities can have a range of histopathologic features, from keratoacanthoma-like to well-differentiated SCC.

Cutaneous Squamous Cell Carcinomas of the Lower Extremities Show Distinct Clinical and Pathologic Features

Cutaneous squamous cell carcinomas mainly affect older, predominantly male patients. Most are due to chronic ultraviolet exposure, and associated with actinic keratoses. On the lower extremities, they occur more commonly in women. However, data on these tumors as a distinct group are scarce. We evaluated 61 squamous cell carcinomas of the lower extremities. Overall, 69% of patients were female. Mean age was 75 years. More than 90% of tumors were well differentiated, 3% showed perineural invasion, and none lymphovascular invasion. In all, 63.9% showed evidence of severe chronic sun damage. Associated actinic keratoses were identified in only 13% of cases. By contrast, 80% were associated with distinctive basal epidermal proliferations with a retiform growth pattern. These proliferations were evaluated immunohistochemically for keratinocyte stem cell markers, p53 and Notch1 in 15 cases. All cases were positive for cytokeratin 14, p53, and Notch1 (with variable intensity in the latter 2), and predominantly negative for cytokeratin 19. Interestingly, basal retiform proliferations were positive for cytokeratin 15 in 66% of cases. Fifteen head and neck squamous cell carcinomas were evaluated in comparison. Those lacked associated basal retiform proliferations except in 1 case. In contrast, 87% were associated with actinic keratoses and 100% with severe chronic sun damage. Actinic keratoses associated with head and neck tumors showed cytokeratin 15 staining only in 7% of cases (P = .003 compared with cytokeratin 15 in basal retiform proliferations associated with leg carcinomas). These findings support the hypothesis that lower extremity squamous cell carcinomas are distinct and may exhibit a pathogenesis less reliant on actinic damage.