2190
Refers to a benign follicular tumor that typically presents as a well-demarcated, firm, mobile, slow-growing nodule, affecting patients in the first and sixth decades of life.
There is no significant gender predominance, however, in a study in the United Kingdom focusing on the pediatric population, the female predominance was 3 to 2, with a maximum peak between 8 and 10 years and an incidence of 1 in 500 to 1 in 2200.
It is the second most common benign skin tumor excised in childhood.
Pilomatricoma is derived the hair-follicle matrix cells.
It is attributed to a mutation in the β-catenin gene of hair-follicle matrix cells together with lymphoid enhancer factor-1 causing unsuppressed β-catenin expression and thus tumor formation.
Most lesions present as a solitary, slow-growing lesion of the head or neck.
Atypical presentations occur in 2% to 3% of cases have and include: abnormal skin pigmentation, painful inflammation or ulceration of overlying skin, or multiple lesions.
It generally progresses over months or years, but in some cases these lesions have grown rapidly.
Histology of centrally located ghost cells enclosed by peripheral basaloid cells is diagnostic.
It has a poor clinical diagnostic accuracy because of the nonspecific presentation.
Pilomatricomas are distinguished by ultrasonography findings of a hypoechoic rim, internal reticulations, and calcifications.
Recommended is a total wide excision.
Prognosis is good, but there is still a recurrence rate of as high as 3%.
Most recurrent lesions occur at a different site.
Cases of malignant transformation into a pilomatrix carcinoma have been reported.
Malignancy is more common among persons from 50 to 79 years old, followed by patients younger than 29 years old, and is 3 to 5 times more common in men.
Malignant lesions are aggressive and tend to recur in approximately 31% of cases months after excision.
Metastasizes to the lung or lymph nodes and other sites have been reported.
Treatment is complete excision with margins of 1 to 2 cm and adjuvant radiotherapy followed by chemotherapy.