Primary cutaneous mucinous carcinoma (PCMC) is a rare, low-grade malignant neoplasm of sweat gland origin (also known as primary mucinous adenocarcinoma of the skin or primary mucinous sweat gland carcinoma), with 0.04 cases per 100 000 person-years.

The average age at diagnosis is 60 years. PCMC typically presents as a slow-growing papule, plaque, or nodule that can be red, pink, gray, blue, or purple. The lesion may have telangiectasias and may develop ulceration or crusting. Lesions are usually smaller than 8 cm and are most common on the eyelid or brow, followed by the rest of the face, scalp, axillae, and trunk. Truncal lesions have been associated with the worst prognoses.

PCMC was initially thought to be most common in men, but recent data has found more cases in females than males. Epidemiologic studies have shown that younger patients have a worse prognosis. Most data suggests that PCMC is most common among White patients, but a recent study revealed a higher prevalence in Black patients.

Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is believed to be a precursor lesion to PCMC, and 50% of patients with EMPSGC have a concomitant invasive lesion.