Merkel cell carcinoma, Bowen's disease and chronic occupational arsenic poisoning

Clinical features and outcomes of Merkel cell carcinoma in 20 cats

The biological behaviour and prognostic factors of Merkel cell carcinoma (MCC) in 20 cats were studied. The tumours were surgically removed and histopathologically examined. The animals were 8 to 20 years old (median age: 14 years), and the tumours were predominantly located in the neck and head. Follow-up data were available in 17 cases, and 12 cats died within a year of surgery. The overall median survival time after resection was 243 days (range 16-360 days). Recurrence occurred in 11 cases, although 6 of them (55%) were found to be margin-negative. Possible metastasis occurred after the surgery in 10 cases, although 6 of them (60%) were found to be margin-negative. The histopathological features of MCC included tumour necrosis in 16 cases (80%), vascular invasion in 6 cases (38%) and high mitotic counts (median: 28.5 per high-power field). Irregular acanthosis was noted adjacent to the tumours in 9 cases (60%). Immunohistochemically, the tumour cells were positive for cytokeratin (CK) 20 and p63 in all cases, synaptophysin in 19 (95%) cases, and CK18 in 16 cases (80%). The study shows that feline MCC is associated with a poor prognosis and exhibited a strong tendency towards local recurrence, regional lymph node metastasis and distant spread.

Molecular characteristics and potential therapeutic targets in Merkel cell carcinoma

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine skin tumour occurring preferentially in elderly and immunosuppressed individuals. Multiple studies have provided insight into the molecular alterations of MCC, leading to the design of several ongoing clinical trials testing chemotherapy, targeted therapy and immunotherapy in patients with recurrent or metastatic disease. The results of some of these studies are available, whereas others are eagerly awaited and will likely shed light on the understanding of MCC biology and potentially improve the clinical outcomes of patients with this rare disease.

Melanotic and non-melanotic malignancies of the face and external ear - A review of current treatment concepts and future options

Skin has the highest incidence and variety of tumors of all organs. Its structure is of great complexity, and every component has the potential to originate a skin neoplasm (SN). Because of its exposed nature, skin is vulnerable to carcinogenic stimuli such as UV radiation. Various entities can cause SN. Nonmelanotic skin cancers (NMSC) are the most common of all cancers, with over one million cases diagnosed annually in the US. Basal cell carcinoma (BCC) accounts for approximately 80% of all NMSC, most of the remaining 20% being squamous cell carcinoma (SCC). The skin of the head and neck is the most common site for tumors, accounting for more than 80% of all NMSC. BCC, SCC, and malignant melanomas (MM) represent 85-90% of all SN. Merkel cell tumors (MCC), lymphoepithelioma-like carcinomas of the skin (LELCS), dermato-fibro-sarcomas, leiomyosarkomas, and Kaposi-sarcomas are less frequent in the facial skin region and the external ear. Based on data from the German Federal Cancer Registry (2003/2004), 140,000 people in Germany were affected by SN (100,000 BCC, 22,000 SCC, 22,000 MM). This number increases considerably if malignant precursors, such as actinic keratosis, are included. Each year, the frequency of SN diagnosis rises by 3-7%. Among all known malignant tumors, MM exhibits the highest rate of increase in incidence. In the past, SN was primarily diagnosed in people aged 50 years or older. However, recently, the risk for developing SN has shifted, and younger people are also affected. Early diagnosis is significantly correlated with prognosis. Resection of SN creates defects that must be closed with local or microvascular flaps to avoid functional disturbing scar formation and deflection of the nose, eyelids, or lips. All therapeutic strategies for SN, the current standard for adjuvant and systemic treatment, and the management of the increasing number of patients under permanent blood thinner medication are described with regard to the treatment of SN.

Merkel cell carcinoma: diagnosis, management, and outcomes

Merkel cell carcinoma is a rare, aggressive cutaneous malignancy with high rates of recurrence, metastases, and mortality. Its nonspecific clinical presentation often delays the diagnosis, and its treatment is still controversial because of the infrequent nature of the tumor. The authors provide an overview of the current literature on epidemiology, cause, pathogenesis, staging, management, and outcomes of this disease. Effective diagnostic and treatment modalities such as wide local excision of the primary tumor, importance of sentinel node biopsy for staging, evidence for the use of adjuvant radiation therapy, and emphasis on a multidisciplinary treatment approach of Merkel cell carcinoma as it pertains to surgical practice are reviewed.

Merkel Cell Carcinoma Concurrent with Bowen's Disease

Merkel cell carcinoma (MCC) is a rare, aggressive cutaneous malignancy of the elderly and immunocompromised patients. It is occasionally found coexisting with other diseases, such as squamous cell carcinoma, basal cell carcinoma, actinic keratosis, miscellaneous adnexal tumors, and rarely Bowen disease. A 75-year-old woman presented with a 6-month history of an irregularly shaped erythematous patch on the left mandibular angle. Three months later, a 1.5×1.0 cm sized painless and rapidly growing erythematous nodule developed on the patch. Microscopically, the patch lesion was consistent with that of Bowen disease. The nodular lesion showed a number of small uniform hyperchromatic cells with scanty cytoplasm. It showed dense small-cell like nodular infiltration in the dermis. Immunohistochemical staining for cytokeratin 20 showed a positive result with a dot-like perinuclear pattern. Additionally, the result for thyroid transcription factor-1 was negative, which is positive in small cell neuroendocrine carcinoma. From these findings, we diagnosed this lesion as MCC concurrent with Bowen disease.

Updated Review of the Pathogenesis and Management of Merkel Cell Carcinoma

Background:

Merkel cell carcinoma is a rare, aggressive, malignant cutaneous tumor of the elderly or immunosuppressed individuals that usually appears on sun-exposed areas of the body. Its pathogenesis is still debated, and, currently, no standardized treatment exists.

Objective:

To provide a current updated review of the most relevant data concerning the pathogenesis and management of Merkel cell carcinoma.

Methods:

Using relevant MeSH terms, we performed a review of the literature on these subjects from 1980 to June 2009.

Results and Conclusion:

The current management of Merkel cell carcinoma is based on surgical excision as the majority of patients present with localized disease, whereas up to 30% have regional lymph node metastases. In these cases, the best outcome is achieved with multidisciplinary management that includes radiotherapy. Chemotherapy is part of the treatment in advanced cases and is mandatory for distant metastatis. Given that a recent work showed the presence of a previously unknown polyomavirus, which the authors called Merkel cell polyomavirus, the therapeutical approach to Merkel cell carcinoma could be reconsidered in the future.

Intraepidermal and dermal Merkel cell carcinoma with squamous cell carcinoma in situ: a case report with review of literature

Merkel cell carcinoma (MCC), a rare aggressive primary cutaneous neuroendocrine carcinoma, occurs on sun-damaged skin, especially in the elderly. Its unique co-expression of cytokeratin 20 (CK20) and neuroendocrine markers, including neuron-specific enolase (NSE), is diagnostic. Most MCCs are located in the dermis, rarely has an intraepidermal component been reported. We report a case of MCC with an intraepidermal component admixed with squamous cell carcinoma in situ (SCCIS). We were able to identify the differences in the immunohistochemical expression pattern between that of the intraepidermal and the dermal components. Most intraepidermal neoplastic cells of MCC in this case showed a less intense immunoreactivity to CK20 and NSE compared to that of dermal neoplastic cells. This case reports an unusual occurrence of combined SCC and MCC that shows both intraepidermal and dermal components.

Noninfectious dermatological diseases associated with chronic exposure to mine tailings in a Peruvian district

BACKGROUND

Mine tailings are metallic wastes which are deposited in the environment due to mining activity. Long-term exposure to these metals is harmful to human health.

OBJECTIVE

To determine if chronic exposure to mine tailings constitutes a risk factor for the development of dermatological diseases in the district of San Mateo de Huanchor (Lima, Peru).

METHODS

An observational case-control study was carried out in the communities of Mayoc, Daza and Tamboraque (exposed to mine tailings, case group) located in the district of San Mateo de Huanchor, and also in the communities of Choccna and Caruya (not exposed to mine tailings, control group) located in the same district. Out of 230 adults, 121 were exposed and 109 were not exposed to mine tailings and out of 135 children, 71 were exposed and 64 were not exposed to mine tailings.

RESULTS

In the adult group, 71% of the exposed cases had some noninfectious dermatological disease while in the nonexposed group the frequency was 34% [P < 0.001; odds ratio (OR) 5.40; 95% confidence interval (CI) 3.02-9.68]. A statistically significant difference between groups was found for arsenical dermatitis, nonpruritic papulovesicular eruption, atopic dermatitis, contact dermatitis, seborrhoeic dermatitis and xerosis. In the paediatric population, 71 exposed and 64 nonexposed children were evaluated. Sixty-nine per cent of the exposed group had some noninfectious dermatological disease vs. 30% in the nonexposed group (P < 0.001; OR 6.00; 95% CI 2.71-13.31). A statistically significant difference between groups was found for xerosis and atopic dermatitis.

CONCLUSION

Chronic exposure to mine tailings represents a risk factor for development of noninfectious dermatological diseases in both adults and children.

Merkel Cell Carcinomas

Merkel cell carcinoma (MCC) is a rare and extremely aggressive skin cancer that arises from primary neural cells. It presents most commonly in the elderly and immunocompromised patients. Pathologically, MCC should be distinguished from extrapulmonary small cell lung cancer or metastatic small cell lung cancer or a small cell variant of melanoma. The prognosis is based largely on the stage of disease at the time of presentation. Therapeutic options for MCC include wide resection with or without adjuvant radiotherapy or chemotherapy. Novel therapies based on the understanding of the molecular aspects of MCC are currently being explored.

Merkel cell cancer of the skin

Merkel cell carcinoma (MCC) is a rare malignant cutaneous tumor of the elderly with rapidly growing skin nodules found predominantly on sun-exposed areas of the body. The vast majority of patients present with localized disease, while up to 30% have regional lymph node metastases. Despite local excision and the incidence of local recurrence, regional lymph node metastases and distant metastases is high and usually occurs within 2 years of primary diagnosis. The optimal treatment for patients with MCC remains unclear. The best outcome is achieved with multidisciplinary management including surgical excision of primary tumor with adequate margins and post-operative radiotherapy (RT) to control local and regional disease. Patients with regional nodal metastases should be treated with lymph node dissection plus RT. Adjuvant chemotherapy (CT) should be considered as part of the initial management. In case of metastatic disease CT based on regimens used for small-cell lung cancer is the standard treatment of care.

Merkel cell carcinoma in patients with long-term ingestion of arsenic

Merkel cell carcinoma (MCC) is a rare primary neuroendocrine carcinoma of the skin, mostly occurring late in life on sun-exposed body parts. Little is known about the specific etiological factors in the pathogenesis of MCC. A previous report indicated that arsenic exposure might cause MCC, which might be another specific type of skin cancer associated with arsenic exposure. On the southwest coast of Taiwan, high arsenic levels in artesian well water have been documented, and various diseases associated with arsenic exposure have been found to be prevalent in this area. We report two pathologically confirmed cases of MCC in patients who had histories of long-term ingestion of arsenic from drinking water. The tumors were on the anterior chest wall, an area less exposed to the sun, in both cases. The literature on the dose-response relationship between arsenic exposure and MCC is limited. We estimated that the total arsenic ingested by these two cases was around 14.7 and 2.6 gm, respectively. We also tried to assess the cancer risk on the basis of the estimated doses of arsenic exposure and the cancer risk model developed by the U.S. Environmental Protection Agency (EPA). The estimated lifetime target cancer risk was 1.3 x 10(-2) in Case 1 and 2.3 x 10(-3) in Case 2. Both are much higher than the 10(-6) upper limit on lifetime cancer risk put forth by the U.S. EPA health protection standard. We believe that arsenic intoxication played an important role in the carcinogenic process of MCC in our cases.

Epidemiology of primary Merkel cell carcinoma in the United States

BACKGROUND

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer.

OBJECTIVE

We sought to describe primary MCC incidence trends, epidemiology, and predictors of survival.

METHODS

The population covered by the Surveillance, Epidemiology, and End Results Program was analyzed as a prospective cohort. We measured age-adjusted incidence rates (per 100,000 person-years) and effect of age, anatomic site, and stage on survival.

RESULTS

Incidence was higher in males (0.34) than in females (0.17). Cases (n = 1034) occurred mostly in whites (94%), in people older than 65 years (76%), and at the head (48%). The 5-year relative survival was 75%, 59%, and 25% for localized, regional, and distant MCC, respectively. Female sex, limb presentation, localized disease, and younger age were positive predictors of survival.

CONCLUSION

The highest incidence of MCC was observed in whites, males, and in people older than 65 years. Only 49% of cases were reported as localized. Better survival was associated with limb localization, early-stage disease, younger age, and female sex.

Primary neuroendocrine (Merkel cell) carcinoma of the skin: morphologic diversity and implications thereof

A significant proportion of primary neuroendocrine cell carcinomas of the skin (Merkel cell carcinomas [MCCs]) have been reported to occur in intimate association with malignant epithelial neoplasms, mainly squamous cell carcinomas. In addition, divergent differentiation within these tumors, particularly of squamous and eccrine types, is not infrequent. This expanded morphologic spectrum of MCC calls for evaluation of potential biologic implications of the phenotypic diversity and begs reconsideration of the histogenesis of the lesion. The current retrospective review of 29 cases of primary cutaneous neuroendocrine cell carcinoma aims to address these issues by integrating new information with that which is extant. Eleven tumors were associated with evolving or established cutaneous carcinomas: 2 actinic keratoses, 5 Bowen's disease, 3 superficial squamous cell carcinomas, and 1 basal cell carcinoma. Two combined squamous-neuroendocrine tumors occurred in recipients of solid organ transplants, and another developed in a Marjolin's ulcer at the site of a previous burn. Squamous and/or adnexal differentiation within the dermal component of the tumor was observed in 4 instances and was significantly associated with MCCs in intimate association with another cutaneous carcinoma. The outcome of the group as a whole is similar to that recorded in previous series of MCC, with local recurrence in 32% of cases and death caused by the neoplasm in 28%. Only 52% of the patients were alive with no history of metastasis at follow-up. No significant difference in outcome was observed between the patients with pure MCCs and those with MCCs in combination with another cutaneous carcinoma.

Merkel cell carcinoma: report of 10 cases and review of the literature

BACKGROUND

Merkel cell carcinoma (MCC) is a rare primary neuroendocrine skin tumor that usually arises in the head and neck or the extremities of elderly patients. Because of the limitation of retrospective data, optimal treatment is not well defined.

OBJECTIVE

Our purpose was to present the clinical course and treatment of 10 patients with MCC and review the published literature on MCC.

METHOD

We conducted a retrospective analysis and obtained detailed clinical information for all 10 patients treated for MCC at our institution from 1986 through 1998. The medical literature was also reviewed for natural history and treatment recommendations using MEDLINE search.

RESULTS

Five men and 5 women received their treatment between 1986 and 1998 for MCC (5 had stage IA disease, 4 stage IB, 1 stage II). The mean age was 70.3 years (range, 47-86 years). Seven tumors were located on the head and neck and 3 on extremities. Five of 10 patients had a relapse (mean time before recurrence, 5.7 months) (range, 2 weeks-20 months); one patient had local recurrence, one had regional lymph node recurrence, and 3 had both local and regional lymph node recurrence. In 4 patients systemic metastases developed. Long survival is also noted (6 to > 164 months); 4 patients died of MCC. After initial surgery, 9 patients received radiotherapy at some point and 3 patients also received chemotherapy. Five of 10 patients had 13 previously treated or coexisting malignant neoplasms. In one patient MCC developed in a previously irradiated field. Review of 875 cases showed a male/female ratio of 1.5:1; location of tumors was as follows: head and neck, 47%; extremities, 40%; trunk, 8%; unknown primary site, 5%. Local recurrence was observed in 25%, regional lymph node involvement in 52%, distant metastasis in 34%, and MCC was a cause of death in 34%.

CONCLUSION

MCC has a high incidence of locoregional recurrence with distant metastases that is more common with higher stage lesions. Early local management of smaller lesions results in good long-term survival. It is not known whether prophylactic lymph node dissection and/or radiation and adjuvant radiation increases survival. Long survival can be achieved after treating locoregional recurrence. The role of chemotherapy is still controversial and should be considered in patients with advanced disease and those not thought to be candidates for surgery.