Merkel cell cancer overview: Difference between revisions
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==Historical Perspective== | ==Historical Perspective== | ||
Merkel cell polyomavirus, the pathogen responsible for Merkel cell cancer, was first discovered in 2008. | [[Merkel cell]] was first discovered by Freidrich Sigmund Merkel and also mentioned by Cyril Toker, in 1972.Merkel cell polyomavirus, the pathogen responsible for Merkel cell cancer, was first discovered in 2008. | ||
==Classification== | ==Classification== | ||
Merkel cell carcinoma is classified into 3 subgroups: trabecular, intermediate, and small cell. | Merkel cell carcinoma is classified into 3 subgroups: trabecular, intermediate, and small cell. | ||
==Pathophysiology== | ==Pathophysiology== | ||
It is understood that [[merkel cell cancer]] is the result caused by either [[merkel cell]] [[polyomavirus]], [[ultraviolet]] (UV), [[radiation exposure]] and [[immunosuppression]]. | |||
==Causes== | ==Causes== | ||
Common causes of [[merkel cell carcinoma]] include [[merkel cell]] [[polyomavirus]], age, skin tone, exposure to [[sunlight]] and history of [[immunosuppression]]. | |||
==Differential Diagnosis== | ==Differential Diagnosis== | ||
Merkel cell cancer must be differentiated from other skin lesions, such as [[basal cell carcinoma]], [[squamous cell carcinoma]], [[malignant melanoma]], [[lymphoma]], vascular tumors, and other benign skin tumors. | [[Merkel cell cancer]] must be differentiated from other skin lesions, such as [[basal cell carcinoma]], [[squamous cell carcinoma]], [[malignant melanoma]], [[lymphoma]], vascular tumors, and other benign skin tumors. | ||
==Epidemiology and Demographics== | ==Epidemiology and Demographics== | ||
The incidence of | The [[incidence]] of [[merkel cell carcinoma]] ranges from 0.15 to 0.44 per 100,000 individuals. The median age at diagnosis is approximately 65 years. [[Merkel cell carcinoma]] is more common among males and individuals of Caucasian race. | ||
==Risk Factors== | ==Risk Factors== | ||
Risk factors for the development of | Risk factors for the development of [[merkel cell cancer]] include old age, male gender, caucasian race, chronic exposure to [[sunlight]], [[immunodeficiency]], and personal history of [[cancer]]. | ||
==Screening== | ==Screening== | ||
According to the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for skin cancers, including | According to the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for [[skin cancers]], including [[merkel cell cancer]]. | ||
==Natural History, Complications and Prognosis== | ==Natural History, Complications and Prognosis== | ||
Merkel cell cancer is an aggressive | [[Merkel cell cancer]] is an aggressive [[cutaneous]] cancer that grows very rapidly. [[Merkel cell cancer]] usually [[Metastasis|metastasizes]] first to regional [[Lymph node|lymph nodes]]. [[Merkel cell cancer]] is a highly aggressive tumor with a [[mortality]] rate that approaches 30% to 40% within 3 years of diagnosis. | ||
==Diagnosis== | ==Diagnosis== | ||
===Staging=== | ===Staging=== | ||
The staging of | The staging of [[merkel cell cancer]] is based on the [[TNM staging system]]. | ||
===History and Symptoms=== | ===History and Symptoms=== | ||
Patients with | Patients with [[merkel cell carcinoma]] usually present with a rapid growing, painless, small [[mass]] that is typically located on sun exposed area of the body. | ||
===Physical Examination=== | ===Physical Examination=== | ||
Physical examination findings of Merkel cell cancer include a firm, dome-shaped or raised, red/violaceous skin mass that appear in sun exposed areas. | Physical examination findings of Merkel cell cancer include a firm, dome-shaped or raised, red/violaceous skin mass that appear in sun exposed areas. | ||
Revision as of 15:15, 23 January 2019
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Ahmad Al Maradni, M.D. [2]
Overview
Merkel cell cancer is a rare and highly aggressive cancer where malignant cancer cells develop on or just beneath the skin and in hair follicles. This cancer is a type of neuroendocrine tumor, like small cell lung cancer. Merkel cell carcinoma is the most serious form of skin cancer. Once it has metastasized to the lymph nodes, the 5-year survival rate for a patient is less than 50 percent. However, small tumors (less than 2 cm) that have not metastasized to the lymph nodes are associated with a 5-year survival rate of more than 90 percent. Recurrence may occur in up to half of all patients.[1] Merkel cell cancer usually manifests on either the face, head, or neck. Patients usually present with a rapid growing, firm, painless, red/violaceous skin lesion. It usually metastasizes first to regional lymph nodes and then to other distant organs. and spreads to other parts of the body, especially the liver, lungs, brain and bones. The predominant therapy for Merkel cell cancer is surgical resection, but adjuctive chemoradiation may also be required in more advanced disease.
Historical Perspective
Merkel cell was first discovered by Freidrich Sigmund Merkel and also mentioned by Cyril Toker, in 1972.Merkel cell polyomavirus, the pathogen responsible for Merkel cell cancer, was first discovered in 2008.
Classification
Merkel cell carcinoma is classified into 3 subgroups: trabecular, intermediate, and small cell.
Pathophysiology
It is understood that merkel cell cancer is the result caused by either merkel cell polyomavirus, ultraviolet (UV), radiation exposure and immunosuppression.
Causes
Common causes of merkel cell carcinoma include merkel cell polyomavirus, age, skin tone, exposure to sunlight and history of immunosuppression.
Differential Diagnosis
Merkel cell cancer must be differentiated from other skin lesions, such as basal cell carcinoma, squamous cell carcinoma, malignant melanoma, lymphoma, vascular tumors, and other benign skin tumors.
Epidemiology and Demographics
The incidence of merkel cell carcinoma ranges from 0.15 to 0.44 per 100,000 individuals. The median age at diagnosis is approximately 65 years. Merkel cell carcinoma is more common among males and individuals of Caucasian race.
Risk Factors
Risk factors for the development of merkel cell cancer include old age, male gender, caucasian race, chronic exposure to sunlight, immunodeficiency, and personal history of cancer.
Screening
According to the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for skin cancers, including merkel cell cancer.
Natural History, Complications and Prognosis
Merkel cell cancer is an aggressive cutaneous cancer that grows very rapidly. Merkel cell cancer usually metastasizes first to regional lymph nodes. Merkel cell cancer is a highly aggressive tumor with a mortality rate that approaches 30% to 40% within 3 years of diagnosis.
Diagnosis
Staging
The staging of merkel cell cancer is based on the TNM staging system.
History and Symptoms
Patients with merkel cell carcinoma usually present with a rapid growing, painless, small mass that is typically located on sun exposed area of the body.
Physical Examination
Physical examination findings of Merkel cell cancer include a firm, dome-shaped or raised, red/violaceous skin mass that appear in sun exposed areas.
Laboratory Findings
There are no laboratory findings associated with Merkel cell cancer.
CT
CT scan is useful in detecting metastasis to organs and regional lymph nodes.
Other Imaging Findings
Positron emission tomography (PET) may be used in staging of Merkel cell cancer.
Other Diagnostic Studies
On biopsy, Merkel cell cancer is characterized by positivity on cytokeratin-20 immunohistochemical staining. On electron microscopy, the presence of neurosecretory granules within cytoplasmic extensions is characteristic.
Treatment
Medical Therapy
The predominant therapy for Merkel cell cancer is surgical resection. Adjunctive chemoradiation may also be required in more advanced disease.
Surgery
The majority of cases of Merkel cell cancer are treated with surgery.
Primary Prevention
Primary prevention of Merkel cell cancer includes avoidance of excessive sun exposure and use of sunscreen.
Secondary Prevention
Secondary prevention of Merkel cell cancer includes avoidance of excessive sun exposure and use of sunscreen.
References
- ↑ Allen PJ, Browne WB, Jaques DP; et al. (2005). "Merkel cell carcinoma: Prognosis and treatment of patients from a single institution". Journal of Clinical Oncology. 23 (10): 2300–2309.