Pilomatricomas are a common benign tumor in children.

Pilomatricomas (aka calcifying epithelioma of Malherbe) arise from the outer root sheath of the hair follicle and are thought to be caused by mutations in the b-catenin gene.

Presents as a skin-colored or bluish subcutaneous nodule that may be rock hard to the touch (Fig. 8.2).

Characteristic secondary calcification is often present and contributes to its firmness.

Lesions are mobile and often have irregular contours.

Most are asymptomatic but some are associated with mild tenderness or pain.

Typically found on the head and neck and less often are seen on the upper extremity or trunk in children (Fig. 8.3).

On the face pilomatricomas are most often found in the periorbital, lateral cheek and preauricular areas.

Most pilomatricomas are solitary, although multiple pilomatricomas do occur.

Diagnosis is based on clinical recognition.

The “tent sign” is a useful clinical test that will show the irregular contours of the nodule when the skin is stretched taut.