Pilomatrix carcinoma (PC; also known as pilomatricial or matricial carcinoma) is a rare cutaneous adnexal malignancy derived from follicular matrix cells. It typically presents as an asymptomatic, rapidly growing mass on the head, neck, or back. Its distribution pattern and frequent occurrence on sun-damaged skin suggest that sun exposure may be a risk factor in its development. It typically arises de novo, but may transform from a benign pilomatrixoma. This transformation can occur either from a stable tumor or from the location of a previously excised mass.

The typical presentation of PC is a rapidly growing, nontender, skin-colored or bluish, 2-4 cm solitary mass, though tumor size has ranged from 0.5-20 cm in diameter. It may be either cystic or solid. In addition to the head, neck, and back, it may also be found on the anterior trunk and extremities. It is most often misdiagnosed as a pilomatrixoma, basal cell carcinoma, epidermal or trichilemmal cyst, or lipoma.

PC is most commonly seen in older men of Northern European descent in the sixth decade of life, though it has been documented in African Americans and individuals of Hispanic descent. It has been diagnosed in children and adults with a male to female ratio of 3-4:1.

Diagnosis of PC typically occurs over a year after it is first recognized by the patient. Even after proper surgical excision, it frequently recurs. It has the potential to metastasize, most commonly spreading to regional lymph nodes, the lungs, bone, and brain. Local recurrence is the best predictor of metastasis.