Merkel cell carcinoma
Merkel cell carcinoma metastasises in 40% of cases, with a five-year survival after metastasis of less than 50%.
Merkel cell carcinoma is rare, with a reported incidence in one study of 2.2 per million per year.1 On the Skin Cancer Audit Research Database (SCARD), there are 21 cases recorded compared to 5717 primary melanomas (one for every 270 melanomas).2
Although these tumours are rare, it is important that they are recognised at first presentation because metastases occur in approximately 40% of cases and five-year survival after metastasis is less than 50%.3
- Consider Merkel cell carcinomafor any elevated, firm and growing (EFG) skin lesion, particularly if the colour is deep red. Biopsy without delay.
- Never treat EFG skin lesions without submitting a specimen for histology.
- Radiotherapy is emerging as the treatment of choice for Merkel cell carcinoma.5 Refer to a radiation oncologist urgently.
C: dermatoscopy of Merkel cell carcinoma
AN 83-year-old man presented for a skin check. A small red lesion, with an appearance similar to a glazed cherry, was noted on his forehead (Figure 1).
Biopsy was scheduled along with five other suspected non-melanoma skin cancers, but before it was done the patient visited a laser-therapist about another matter and she attempted laser ablation of the forehead lesion without taking a biopsy.4
Subsequent tissue-salvage biopsy discovered a 3mm focus of dermally based Merkel cell carcinoma. Radiotherapy treatment was initiated. During the course of radiotherapy, multiple cutaneous metastases appeared on the other side of the forehead (Figure 2).
Dr Alan Cameron, MBBS, FSccanz
Lecturer at the School of Medicine, The University of Queensland
Co-author: Dr Cliff Rosendahl, MBBS, FSccanz
Tags: , Dermoscopy