The key histologic feature of MCC is a perinuclear dot pattern of cytokeratin-20, "which is the rule, not the exception," he said.
Dr. Nghiem finds MCC treatment guidelines from the National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology to be especially useful. The guidelines are updated annually and are available at www.nccn.org
MCC typically is coded as ICD-9 code 173 (other malignant neoplasm of skin). "Unfortunately, this means that MCC costs can't be tracked at all and, more importantly, patients are denied care," he said. Things should improve on that front shortly, however. Dr. Nghiem said that the CDC is expected to release eight new diagnostic codes specific for MCC this month.
Little is known about MCC biology, but a study from 2008 found that a new polyomavirus is present in the vast majority of cases (Science 2008;319:1096-100). "This is only the sixth example of a virus clearly linked to human cancer," Dr. Nghiem said.
He disclosed that he has received funding from the National Institute of Arthritis and Musculoskeletal and Skin Diseases and the American Cancer Society.
The majority of Merkel cell carcinoma lesions appear on sun-exposed skin, but one in six has been found to appear on sun-protected areas.
Merkel cell carcinoma has a significantly higher mortality rate, compared with melanoma, and reported incidence has increased threefold since 1986.
Source Photos courtesy Dr. Paul Nghiem