Imaging of Merkel Cell Carcinoma: What Imaging Experts Should Know

Radiographics. 2019 Nov-Dec;39(7):2069-2084. doi: 10.1148/rg.2019190102.


Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous neuroendocrine tumor with a higher mortality rate than melanoma. Approximately 40% of MCC patients have nodal or distant metastasis at initial presentation, and one-third of patients will develop distant metastatic disease over their clinical course. Although MCC is rare, its incidence has been steadily increasing. Furthermore, the immunogenicity of MCC and its diagnostic and therapeutic application have made MCC one of the most rapidly developing topics in dermatology and oncology. Owing to the aggressive and complex nature of MCC, a multidisciplinary approach is necessary for management of this tumor, including dermatologists, surgeons, radiation oncologists, medical oncologists, pathologists, radiologists, and nuclear medicine physicians. Imaging plays a crucial role in diagnosis, planning for surgery or radiation therapy, and assessment of treatment response and surveillance. However, MCC is still not well recognized among radiologists and nuclear medicine physicians, likely owing to its rarity. The purpose of this review is to raise awareness of MCC among imaging experts by describing the epidemiology, pathophysiology, and clinical features of MCC and current clinical management with a focus on the role of imaging. The authors highlight imaging findings characteristic of MCC, as well as the clinical significance of CT, MRI, sentinel lymph node mapping, fluorine 18 fluorodeoxyglucose PET/CT, and other nuclear medicine studies such as bone scintigraphy and somatostatin receptor scintigraphy. ©RSNA, 2019.

Publication types

  • Review
  • Webcast

MeSH terms

  • Antibodies, Viral / blood
  • Bone Neoplasms / diagnostic imaging
  • Bone Neoplasms / secondary
  • Carcinoma, Merkel Cell / diagnostic imaging*
  • Carcinoma, Merkel Cell / secondary
  • Carcinoma, Merkel Cell / virology
  • Humans
  • Lymphatic Metastasis / diagnostic imaging
  • Magnetic Resonance Imaging / methods*
  • Merkel cell polyomavirus / isolation & purification
  • Neoplasm Staging
  • Oncogene Proteins / immunology
  • Polyomavirus Infections / diagnostic imaging
  • Polyomavirus Infections / virology
  • Positron Emission Tomography Computed Tomography / methods*
  • Prognosis
  • Radiopharmaceuticals / analysis
  • Radiopharmaceuticals / pharmacokinetics
  • Receptors, Somatostatin / drug effects
  • Sentinel Lymph Node Biopsy
  • Skin Neoplasms / diagnostic imaging*
  • Skin Neoplasms / virology
  • Tumor Virus Infections / diagnostic imaging
  • Tumor Virus Infections / virology
  • Viral Proteins / immunology


  • Antibodies, Viral
  • Oncogene Proteins
  • Radiopharmaceuticals
  • Receptors, Somatostatin
  • Viral Proteins