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Pathogenesis, clinical features, and diagnosis of Merkel cell (neuroendocrine) carcinoma

Patricia Tai, MB, BS, DABR, FRCR, FRCPC
Section Editors
Robert S Stern, MD
June K Robinson, MD
Deputy Editor
Rosamaria Corona, MD, DSc


Merkel cell carcinoma (MCC) of the skin is a rare, aggressive cutaneous malignancy that predominantly affects older adults with light skin types and has a propensity for local recurrence and regional lymph node metastases [1]. A variety of other terms have been used to describe this tumor, including neuroendocrine or primary small cell carcinoma of the skin, trabecular cell carcinoma, APUDoma of the skin, and anaplastic cancer of the skin.

The epidemiology, pathogenesis, clinical features, and diagnosis of MCC are discussed here. The staging and treatment of patients with MCC are discussed separately. (See "Staging and treatment of Merkel cell carcinoma".)


Incidence — MCC was first described in 1972 [2]. Data from the Surveillance, Epidemiology and End Results (SEER) Program database indicate that MCC is uncommon; the estimated annual incidence rate in 2006 was 0.6 per 100,000 persons [3]. Incidence rates were higher in males compared with females (0.41 and 0.18 cases per 100,000 person-years, respectively).

Higher incidence rates are reported in Australia and New Zealand [4-6]. Data from the Queensland Cancer Registry indicate an average annual incidence of 1.6 per 100,000 between 2006 and 2010, with a peak rate of 20.7 per 100,000 for individuals 80 years or older [4]. Data from Western Australia between 1993 and 2007 indicate an annual incidence of 0.82 per 100,000 and 15.5 per 100,000 for individuals ≥85 years [6]. An annual incidence of 0.88 per 100,000 has been reported in New Zealand between 2002 and 2011, with a peak rate of 17.6 per 100,000 among individuals ≥85 years [5].

Risk factors — MCC predominantly affects persons with light skin. A study analyzing SEER data from 1973 to 2006 found that 95 percent of cases diagnosed during this interval arose in the white population [3].

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Literature review current through: Oct 2017. | This topic last updated: May 10, 2017.
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