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Malignant Neoplasms
Published in Ayşe Serap Karadağ, Lawrence Charles Parish, Jordan V. Wang, Roxburgh's Common Skin Diseases, 2022
Mark Biro, Vesna Petronic-Rosic
Overview: The mean age at diagnosis for MCC is 75 years old, and it is more commonly found in Caucasian patients. MCC is associated with integration of Merkel cell polyomavirus DNA into host cells, eventually leading to loss of cell cycle regulation in Merkel cells. Although approximately 60–80% of the general population have been infected by the Merkel cell polyomavirus, other host factors associated include ultraviolet radiation, immunosuppression, organ transplantation, and HIV infection.
Non-Melanoma Skin Cancer
Published in Pat Price, Karol Sikora, Treatment of Cancer, 2020
Irene De Francesco, Sean Whittaker, Stephen L. Morris
Merkel cells are specialized sensory cells present in the basal or supra-basal layers of the epidermis. They are believed to be neurosensory cells that are derived from the amine precursor uptake and decarboxylation system (APUD). They function as slowly adapting type 1 mechanoreceptors, with a higher density in sun-exposed areas. Forty-seven per cent of cases occur on the head and neck, 40% on the extremities, and 8% on the trunk.288 Risk factors include UV light and immunosuppression.289–293 Rapid progression of MCC occurs with immunosuppressive therapy after organ transplantation.294 A similar pattern of genomic changes has been detected in MCC and neuroendocrine tumors such as melanoma.285 In metastatic MCC, Bcl2 is strongly expressed. In a severe combined immunodeficient (SCID) mouse xeno-transplantation model for human MCC, administration of BCL2 antisense oligonucleotide results in either a dramatic reduction of tumor growth or CR.295 In 2008, the Merkel cell polyoma virus was reported in MCC tumor specimens.296 High levels of clonal integration of the virus in Merkel cell tumors has been reported, but not all cases are associated with the virus infection.297 There may be two independent pathways for the development of MCC, one driven by the virus and the other by sun damage.
Merkel cell carcinoma
Published in Longo Caterina, Diagnosing the Less Common Skin Tumors, 2019
Merkel cell carcinoma (MCC) is a rare, very aggressive neuroendocrine tumor of the skin characterized by frequent recurrences and early metastatic spread. The incidence of MCC has tripled in recent years and is today estimated at about 0.24 per 100,000 person-years. MCC shows a predilection for elderly white men and immunosuppressed patients. Found in approximately 80% of tumors, the Merkel cell polyomavirus (MCV) could play a key etiologic role. MCC usually develop on chronically sun-damaged skin. The most common sites of presentation are the head and neck region and extremities, followed by the trunk and oral and genital mucosa. Clinically it can range from erythematous plaques to erythematous or red, sometimes violaceous, sharply demarcated nodules with a smooth and shiny surface (Figure 34.1a, b). However, in the majority of cases MCC are “cherry red” in color, that is to say strikingly deep cherry red, a color spectrum ranging from dark red to violaceous, which helps to distinguish MCC from other red nodules such as Basal cell Carcinoma (BCC) and squamous cell carcinoma (SCC), which tend to be more pink (Figure 34.2a, b). Often they appeared opalescent. Tumor growth is usually very rapid. The most important clinical features of MCC are summarized under the acronym AEIOU: asymptomatic, rapid expansion, immunosuppression, older patient and located on UV-damaged skin.
Pembrolizumab and other immune checkpoint inhibitors in locally advanced or metastatic Merkel Cell Carcinoma: safety and efficacy
Published in Expert Review of Anticancer Therapy, 2020
Antoine Marchand, Thibault Kervarrec, Shailender Bhatia, Mahtab Samimi
The discovery of the Merkel Cell Polyomavirus (MCPyV) in 2008 as the causative agent of approximately 80% of MCCs [6] has accelerated research in understanding the biology, and subsequently treatment paths, of this hitherto orphan cancer. Until recently, treatment for metastatic disease relied on platinum-based chemotherapy regimens, often combined with etoposide [3–5]. MCC is indeed a chemo-sensitive cancer, with response rates ranging from 30% to 75% after a first line of chemotherapy. However, chemo-resistance occurs rapidly, and median progression-free survival (PFS) and overall survival (OS) after first-line chemotherapy respectively remain as low as 3 and 9.5 months, and further fall to 2 and 4.5 months after a second-line chemotherapy, with response rates below 20% [7–11]. These drugs frequently induce serious side effects, including hematologic toxicity and nephrotoxicity, in these frequently old and fragile patients.
Advanced neuroendocrine carcinoma (Merkel cell carcinoma) of the vulva: a case report and literature review
Published in Southern African Journal of Gynaecological Oncology, 2020
Adam R Botha, Langanani Mbodi, Reubina Wadee
The pathogenesis of vulval neuroendocrine carcinomas has not been extensively studied. Studies of vulval and non-vulval Merkel cell carcinoma have suggested infection by a polyomavirus termed Merkel cell polyomavirus13,2185 and UV light exposure20 as pathogenetic mechanisms. The exact origin of Merkel cells has been a point of debate for many years, with recent suggestions of pre-B cell lymphoid origin, as demonstrated by a study of 21 cases by Jankowski et al.24 of non-vulval Merkel cell carcinoma, which showed immunohistochemical staining for terminal deoxynucleotidyl transferase (TdT) and paired box protein 5 (PAX 5). Immunohistochemical cross-reactivity between PAX5, PAX2 and PAX8 expression has also been documented.25 Whilst it may currently be too soon to suggest a B-cell origin of Merkel cell carcinoma, it is important to bear in mind that positive staining of TdT and PAX5 in Merkel cell carcinoma may be a diagnostic pitfall as these markers tend to be identified in B-cell lymphoblastic lymphomas/leukaemias.
Biologic TNF-alpha inhibitors in the treatment of Stevens-Johnson syndrome and toxic epidermal necrolysis: a systemic review
Published in Journal of Dermatological Treatment, 2020
Shan Zhang, Shunli Tang, Sheng Li, Yunlei Pan, Yingguo Ding
Two case reports, one case series and one small RCT used infliximab or etanercept in combination with other systemic therapies, comprising 10 patients. Among them, four patients utilized the similar treatment protocol, consisting of 500 mg methylprednisolone bolus i.v., 5 mg/kg i.v. infliximab and an IVIG treatment cycle (2 g/kg over five days) (30,31). The lesions improved rapidly and recovered completely, except one TEN case died from multiorgan dysfunction caused by a catheter-related bacteremia in spite of evident skin reepithelialization (30). Maximova et al. (33) reported a 21-year-old girl suffered from SJS after bone marrow transplant for relapsed T-cell acute lymphatic leukemia. No suspicious drug was discovered but Merkel cell polyomavirus DNA was detected in skin lesions and blood from the patient. She was then administered with IVIG 1 g/kg for five days together with methylprednisolone 2 mg/kg/die and etanercept 25 mg. After 44 days, she was in complete remission except for cheratitis and vulvitis, which persisted for months.