Juan Vicente de la Sota, Beatriz Losada Vila, Diego Malón Giménez and Jesús Canora Lebrato
Merkel cell carcinoma (MCC) is an uncommon neuroendocrine tumor that represents a small percentage of skin malignancies, with an aggressive behavior and survival rate at 5 years of 20% to 80%. Among the risk factors, we find Ultraviolet radiation, polyomavirus, other malignancies and immunosuppression.
Most of the MCC are diagnosed over 59 years old, being more frequent in men. According to the literature, only 2% to 5% had no skin involvement. Among regions involved, head and neck are the most frequent, followed by limbs and lymph nodes.
We described a case of MCC without skin involvement, atypically located in retroperitoneum and given the rarity of both circumstances, we also conducted a review of the reported cases of retroperitoneal MCC without skin tumor.
Among retroperitoneal MCC without primary skin involvement, we found 13 reported cases, the average age of these patients was 66 years old, being female only one case. They were all diagnosed by computerized tomography (CT) or Positron emission tomographycomputed tomography (PET-CT). The size of the main mass was variable (15 cm to 3 cm) and selected treatments were chemotherapy, surgery and radiation therapy. Survival rate is unknown in most of them.
