Primary neuro-endocrine carcinoma of the skin. Management of 13 cases.

Introduction. Since the description by Toker in 1972, neuroendocrine carcinoma or Merkel cell carcinoma, is a well identified clinical entity although the appropriate treatment is still debated. Wide surgical exeresis is indicated as first line treatment in all cases but the question concerning protocols for adjuvant radiotherapy or chemotherapy remains open. We analyzed retrospectively our series of 13 patients with neuroendocrine carcinoma looking for an association between radiotherapy and surgery. Patients. There were 7 women and 6 men in our study population (age range 43-88 years). Two cancers of the rectum and one prostate cancer were associated. In 6 cases, the tumor was localized on the limbs, in 5 on the face and in 2 on the buttocks. Mean delay to diagnosis was 2.5 months. At diagnosis, only 1 patient had satellite nodes. The pathology examination evidenced intermediary cell type and architecture. Immunohistochemistry tests were positive for NSE, NF, KI1 and the ultrastructure confirmed the diagnosis. Nine patients were treated with surgical exeresis with wide 1 cm margins and was completed with radiotherapy of the tumoral bed at homogeneous doses of 45 to 60 Gy. Surgery alone was used in 4 patients. Results. Mean follow-up was 27 months (5-98). Among the 13 operated patients, 11 have survived, 1 died due to the neoplasia and in 1 other from another cause. Local and regional recurrence rate after exeresis alone was 50 p. 100(2/4) with concomitant development of metastasis in both cases. When local or locoregional post-operative radiotherapy was given, local or regional recurrence rate was 33 p. 100 (2/6). Discussion. Cutaneous neuroendocrine carcinoma or Merkel cell carcinoma is an uncommon skin tumor. It is difficult to determine the management protocol on the basis of data in the literature. Due to risk of locoregional recurrence, we currently propose post-operative radiotherapy of the tumor bed and drainage nodes in all patients.