Primary Mucinous Carcinoma of the Skin
Primary mucinous carcinoma of the skin (PMCS) is a rare malignant adnexal tumor. Misdiagnosis of PMCS is common, as it has an uncharacteristic gross appearance and may microscopically resemble cutaneous metastasis from a mucinous carcinoma of the breast, gastrointestinal tract, lungs, ovaries, or prostate. It is important to distinguish between metastatic tumors and PMCS because PMCS generally is more benign and has a better prognosis.
The recommended treatment of PMCS varies from standard excision to wide local excision including dissection of the regional lymph nodes. Alam et al14 reported that Mohs micrographic surgery may be appropriate for first-line therapy because the procedure gives complete margin control and spares tissue. Immunohistochemistry should be used as an adjunct to routine hematoxylin and eosin staining to aid in ensuring negative margins.15 Considering a high potential for recurrence following surgical excision, it is important to detect hormone receptors in this tumor because patients may be treated using antiestrogenic drugs such as tamoxifen. Moreover, recurrent or metastatic PMCS is both resistant to radiotherapy and unresponsive to chemotherapy.3 Annual follow-up is recommended due to the potential for recurrence or metastasis.
