From the Research
Primary mucinous adenocarcinoma of the skin has a relatively low metastatic incidence, with the most recent and highest quality study suggesting an incidence rate of less than 0.1 per million 1. This cancer typically presents as a slow-growing, painless nodule most commonly found on the head and neck, particularly the eyelid region, though it can occur anywhere on the body. The low metastatic potential distinguishes it from metastatic mucinous adenocarcinomas originating from other organs (such as breast, gastrointestinal tract, or lung) that have spread to the skin. When metastasis does occur, it usually involves regional lymph nodes first, with distant metastasis being extremely rare. The low metastatic rate is attributed to the tumor's biological behavior, which includes well-circumscribed growth and abundant mucin production that may physically contain tumor cells. Despite the low metastatic potential, wide local excision with clear margins remains the standard treatment, and patients should undergo thorough clinical evaluation to exclude the possibility that the skin lesion represents metastasis from an internal primary tumor. Some key points to consider in the diagnosis and management of primary mucinous adenocarcinoma of the skin include:
- The importance of clinicopathological correlation, histopathology, and immunohistochemistry in the accurate diagnosis of primary mucinous adenocarcinoma of the skin 1.
- The use of immunohistochemical panels to differentiate primary from metastatic mucinous carcinoma of the skin, including markers such as CK7, p63, and CK5/6 2.
- The need for long-term follow-up due to the possibility of local recurrence, which occurs more frequently than metastasis 3.
- The role of Mohs micrographic surgery in reducing recurrence rates and improving outcomes in primary mucinous adenocarcinoma of the skin 4.