Merkel cell carcinoma in situ: A systematic review of prognosis and management

• Published in: Australasian journal of dermatology Vol. 63; no. 1; pp. e6 - e12
• Main Authors: Truong, Kelvin, Goldinger, Simone M, Chou, Shaun, Howle, Julie R, Veness, Michael J, Fernandez‐Peñas, Pablo, Varey, Alexander H R
• Format: Journal Article
• Language: English
• Published: Australia Wiley Subscription Services, Inc 01.02.2022
• Subjects: Biopsy; carcinoma in situ; Carcinoma in Situ - mortality; Carcinoma in Situ - pathology; Carcinoma in Situ - therapy; Carcinoma, Merkel Cell - mortality; Carcinoma, Merkel Cell - pathology; Carcinoma, Merkel Cell - therapy; Case reports; Clinical trials; Humans; intraepidermal merkel cell carcinoma; Invasiveness; Literature reviews; Lymph nodes; Lymphatic system; management; Medical prognosis; merkel cell carcinoma; merkel cell carcinoma in situ; Neuroendocrine tumors; Prognosis; Radiation therapy; Skin Neoplasms - mortality; Skin Neoplasms - pathology; Skin Neoplasms - therapy; Systematic review; carcinoma in situ; merkel cell carcinoma in situ; merkel cell carcinoma; management; intraepidermal merkel cell carcinoma; systematic review; prognosis
• ISSN: 0004-8380; 1440-0960; 1440-0960
• DOI: 10.1111/ajd.13758

Background Merkel cell carcinoma (MCC) is a rare primary cutaneous neuroendocrine tumour. While dermally invasive MCC is known to have a five‐year survival of only 30‐40%, the prognosis and management of MCC in situ (MCCis) is not widely reported. Objective We present a systematic review to elucidate the prognosis and management of MCCis. Methods We performed a systematic review, searching three databases to 01 June 2021. Case reports, cohort studies, clinical trials and literature reviews were considered for inclusion. Results We identified 26 cases of MCCis published in the literature with a median age of 74 years and involving 19 males and 7 females. Most cases were on the face and neck (n = 17), followed by upper limb (n = 8) and lower limb (n = 1). Sentinel lymph node biopsy was performed in three patients, and all were negative. One subject underwent adjuvant radiotherapy. No MCCis‐associated deaths were reported. Conclusion This review suggests that MCCis has an excellent prognosis with minimal, if any, risk of mortality and a very low risk of dermal invasion and recurrence when treated with wide local excision alone. Sentinel lymph node biopsy is unlikely to be useful for MCCis.