Merkel cell carcinoma: An update and review: Pathogenesis, diagnosis, and staging

What's new in HIV dermatology?

HIV has long been associated with a number of inflammatory, infectious, and neoplastic skin conditions. In the era of anti-retroviral therapy, we have discovered even more about the relationship between skin disease and chronic immunosuppression. In particular, clinicians still face the propensity of persons living with HIV to develop difficult-to-control viral infections, chronic skin inflammation, and pruritus and—particularly as patients age—various types of skin cancers. Here, we summarize recent updates in the field of HIV dermatology and make recommendations to providers caring for these patients.

A Report of 13 Cases of Merkel Cell Carcinoma: Single-Center Experience and Review of the Literature

Background

There is limited data knowledge of Merkel cell carcinoma (MCC) in Turkey aside from a few case reports.

Objective

The aim of this study was to describe the clinical characteristics, demographic features, therapeutic parameters, and outcome of primary cutaneous MCC cases from Turkey.

Methods

Digital medical records of the 13 MCC patients who were followed-up at a tertiary referral center were retrospectively analyzed. Clinic, demographic, tumor characteristics, and survival of the patients were retrieved.

Results

Most of our patients were elderly. Female predominance was noticed. The most common primary site of the tumors was the lower extremities. The overall survival was 42 months, 68% at first year, 68% at third years, and 29% at fifth years.

Conclusion

This is the first largest report from Turkish population with female predominance, and lower extremity tendency.

Merkel cell carcinoma in situ: New insights into the cells of origin

We report a case of a 71-year-old male who presented with a small skin-coloured plaque on his cheek. Histopathology demonstrated an intraepidermal carcinoma with follicular involvement. No evidence of dermal invasion was seen. Immunohistochemical studies showed areas of positive staining for CK20, EMA and synaptophysin. Histopathology findings were found to be most consistent with a diagnosis of intraepidermal carcinoma with features of Merkel cell carcinoma in situ, in combination with a squamous cell carcinoma in situ, with follicular involvement. Recent advances and findings suggest Merkel cell polyomavirus MCPyV-positive Merkel cell carcinoma and MCPyV-negative Merkel cell carcinoma have different cells of origin from different germ layers.

The Dynamics of the Skin's Immune System

The skin is a complex organ that has devised numerous strategies, such as physical, chemical, and microbiological barriers, to protect the host from external insults. In addition, the skin contains an intricate network of immune cells resident to the tissue, crucial for host defense as well as tissue homeostasis. In the event of an insult, the skin-resident immune cells are crucial not only for prevention of infection but also for tissue reconstruction. Deregulation of immune responses often leads to impaired healing and poor tissue restoration and function. In this review, we will discuss the defensive components of the skin and focus on the function of skin-resident immune cells in homeostasis and their role in wound healing.

Sentinel lymph node biopsy in Merkel cell carcinoma: Predictors of sentinel lymph node positivity and association with overall survival

BACKGROUND

Merkel cell carcinoma (MCC) is a rare, aggressive malignancy with high rates of recurrence and metastasis.

OBJECTIVE

To evaluate predictors of sentinel lymph node (SLN) positivity in MCC using the National Cancer Database.

METHODS

The National Cancer Database, from 2012 to 2014, was used to identify 3048 patients with MCC, of whom 1174 received an SLN biopsy. Predictors of SLN positivity were evaluated using logistic regression. Overall survival was evaluated using a Cox proportional hazards model.

RESULTS

Of patients who underwent SLN biopsy, those with primary lesions on the trunk (odds ratio, 1.98; 95% confidence interval [CI], 1.23-3.17; P = .004), tumor-infiltrating lymphocytes (odds ratio, 1.58; 95% CI, 1.01-2.46; P = .04), or lymphovascular invasion (odds ratio, 3.45; 95% CI, 2.51-4.76; P < .001) were more likely to have positive SLNs on multivariate analysis. Overall survival was negatively affected by age ≥75 years (hazard ratio [HR], 2.55; 95% CI, 1.36-4.77; P = .003), male sex (HR, 1.78; 95% CI, 1.09-2.91, P = .022), immunosuppression (HR, 3.51; 95% CI, 1.72-7.13; P = .001), and SLN positivity (HR, 3.15; 95% CI, 1.98-5.04; P < .001).

LIMITATIONS

Lack of disease-specific survival and potential selection bias from a retrospective data set.

CONCLUSIONS

Truncal MCC, tumor-infiltrating lymphocytes, and presence of lymphovascular invasion were independent predictors of positive SLNs. Overall survival was negatively affected by advancing age, male sex, immunosuppression, and SLN positivity.

Radiofrequency ablation of isolated liver metastasis from facial Merkel cell carcinoma

Merkel cell carcinoma is a highly aggressive skin neuroendocrine tumor with early malignant potential. Metastasis was previously considered a sign of unresectability and short life expectancy. This report describes an isolated metastasis to the liver from Merkel cell carcinoma of the left frontotemporal area and an effective treatment that may meaningfully prolong life.

A case report of eyelid Merkel cell carcinoma occurring under treatment with nivolumab for a lung adenocarcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is a rare neuroendocrine malignancy of the skin characterized by high aggressiveness. Four main factors are implicated in its development: immunosuppression, ultraviolet radiation, age and the Merkel cell polyomavirus (MCPyV). In recent years, immune checkpoint inhibitors have shown clinical activity in MCC treatment.

CASE PRESENTATION

We report the case of an 82-year-old man with a lung adenocarcinoma diagnosis, who underwent immunotherapy with nivolumab as second-line treatment. Seven months after the diagnosis of lung cancer during the nivolumab treatment, the patient developed an eyelid MCC, initially misdiagnosed as a chalazion. A palliative radiotherapy was performed with clinical benefit. After a total of seven cycles of nivolumab, computed tomography showed a lung and cerebral disease progression. In addition, clinical conditions worsened leading to the patient's death 13 months after the initial lung cancer diagnosis.

CONCLUSIONS

Cases of co-occurrence of MCC and non-small cell lung cancer (NSCLC) have rarely been reported. Interestingly, common risk factors may be postulated for both cancers. Considering the rarity of this adverse event, its short-term temporal relation with the administration of the drug, which makes a relation improbable, and the coexistence of other risk factors, which may provide plausible explanations, it is possible to conclude according to the WHO Adverse Reaction Terminology that a causal relation between the occurrence of this serious adverse event and the exposure to the drug is unlikely. However, the case deserves to be reported in the literature.

Epidemiology of Merkel cell carcinoma. A population-based study from 1985 to 2013, in northeastern of France

Merkel Cell Carcinoma (MCC) is an aggressive skin cancer with an increasing incidence. Population-based epidemiologic data about MCC in France are rare. Our study aims to describe the epidemiology of MCC in Bas-Rhin, Northeastern of France, between 1985 and 2013. Data were collected from the Bas-Rhin Cancer Registry. We measured age-adjusted incidence rates (per 100,000 person-years) and effect of age, sex and period of diagnosis on survival. The world age-standardized incidence rate was 0.17 and it quadrupled between 1985 and 2013. Cases (n = 111) occurred mostly in women (60%) and in persons ≥70 years of age (74%). Incidence rates was close for men (0.18) and women (0.16) and was 25-time higher in people ≥70 years of age but incidence rate similarly increased between 1985 and 2013 in persons older and younger than 70 years. Net 5-year survival was 48.5%; female sex and younger age were positive predictors of survival. Given the low number of cases, incidence and survival data should be interpreted with caution. Incidence of MCC in Bas-Rhin quadrupled between 1985 and 2013. The highest incidence rate was observed in people ≥70 years. Better survival was associated with female sex and younger age. We hypothesize that MCC will still increase and be diagnosed in increasingly younger patients in next generations.

Cellular sheddases are induced by Merkel cell polyomavirus small tumour antigen to mediate cell dissociation and invasiveness

Merkel cell carcinoma (MCC) is an aggressive skin cancer with a high propensity for recurrence and metastasis. Merkel cell polyomavirus (MCPyV) is recognised as the causative factor in the majority of MCC cases. The MCPyV small tumour antigen (ST) is considered to be the main viral transforming factor, however potential mechanisms linking ST expression to the highly metastatic nature of MCC are yet to be fully elucidated. Metastasis is a complex process, with several discrete steps required for the formation of secondary tumour sites. One essential trait that underpins the ability of cancer cells to metastasise is how they interact with adjoining tumour cells and the surrounding extracellular matrix. Here we demonstrate that MCPyV ST expression disrupts the integrity of cell-cell junctions, thereby enhancing cell dissociation and implicate the cellular sheddases, A disintegrin and metalloproteinase (ADAM) 10 and 17 proteins in this process. Inhibition of ADAM 10 and 17 activity reduced MCPyV ST-induced cell dissociation and motility, attributing their function as critical to the MCPyV-induced metastatic processes. Consistent with these data, we confirm that ADAM 10 and 17 are upregulated in MCPyV-positive primary MCC tumours. These novel findings implicate cellular sheddases as key host cell factors contributing to virus-mediated cellular transformation and metastasis. Notably, ADAM protein expression may be a novel biomarker of MCC prognosis and given the current interest in cellular sheddase inhibitors for cancer therapeutics, it highlights ADAM 10 and 17 activity as a novel opportunity for targeted interventions for disseminated MCC.

Predictors of survival in neurometastatic Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is a rare cutaneous malignancy of neuroendocrine origin, with about 30 cases of brain metastasis (BM) reported in the literature. Historically, the treatment of neurometastatic MCC has largely included chemotherapy and radiotherapy. The aim was to investigate predictors of overall survival (OS) in neurometastatic MCC.

METHODS

In this retrospective study, we surveyed institutional databases and conducted a systematic review of the literature to identify cases reporting on management of distant MCC BM. A pooled survival analysis was performed on the institutional and literature cases to assess predictors of OS.

RESULTS

Forty cases were included for analysis, describing operative [14] and non-operative [26] management. Median time to central nervous system involvement was 17.0-mos (interquartile range 10.5-26.5), and most patients had a single BM (62.5%). Management of intracranial disease included radiotherapy (82.5%), systemic therapy (59.5%) and surgical resection (35%). Operative management was associated with a lower intracranial burden of disease (BoD), but similar systemic BoD. Both neurosurgery (hazard ratio [HR] 0.18, 95% confidence interval [CI]: 0.06-0.54, p = 0.002), having RT (HR 0.37, 95% CI: 0.14:0.93, p = 0.04) and having a single BM (extensive intracranial BoD: HR 2.51, 95% CI: 1.12-5.6, p = 0.03) conferred an OS benefit on risk-unadjusted analysis. Only, neurosurgical resection was an independent predictor of OS (HR 0.12, 95% CI: 0.03-0.49, p = 0.003), controlling for age, BoD and radiotherapy.

CONCLUSIONS

Resection of MCC BM may confer a survival benefit given appropriate patient selection. Prospective investigation of multimodal management of neurometastatic MCC is warranted, especially given the promise of new immunotherapy agents in treating MCC.

Treatment of a Patient with Merkel Cell Skin Carcinoma Using Radiation Therapy - A Case Report

BACKGROUND:

Merkel cell carcinoma (MCC) is a rare, very aggressive tumour. The pathogenesis remains unclear, but UV radiation, immunosuppression, and the presence of Merkel cell polyomavirus in the tumour genome appear to have a key role. Merkel cell carcinoma is a highly aggressive tumour that often has a lethal end.

CAS REPORT:

A patient at 93 years of age comes for an examination by a dermatologist due to a rapidly growing nodular tumour growth in the forehead area. A tumour was about 3 cm in size. It had no signs of basal-cell carcinoma, no arborising vascularisation, no pigmentations on dermoscopy. Clinically, an eventual Merkel cell carcinoma was considered for the patient, but other primary skin tumours had to be excluded, as well as the possibility that regarding the patient’s age, it may be a metastatic deposit. A skin biopsy was performed, as well as H-E examination and immunohistochemical analyses (positive CD56, positivity of neuroendocrine markers synaptophysin, chromogranin) which were in favour of Merkel cell carcinoma of the skin. After setting the diagnosis, our patient was treated with therapy which led to a complete withdrawal of a tumour. However, after 3 months the patient had repeated relapse of a tumour at the same site on the forehead and metastases in the retroauricular lymph nodes bilaterally. It shows that the radiotherapy as monotherapy has a great effect on the removal of the tumour formation, but unfortunately, it has no impact on lesion recurrence. It is also compatible with the literature data.

CONCLUSION:

In many adult patients, as our case suggests, radiotherapy could be a good palliative treatment opportunity that should be considered, as well as a combination of radiation therapy with other oncologic therapeutic options.