Pilomatrixoma, also known as pilomatricoma and calcifying epithelioma of Malherbe, is a benign tumor of the hair follicle. It was initially described by Malherbe and Chenantois in 1880 as a “calcified epithelioma,” believed to derive from the sebaceous gland.¹ In 1949, Lever and Griesemer² suggested an origin from the hair matrix cells.

Pilomatrixoma can occur in any hair-bearing area of the body, although it occurs most often in the skin of the head and neck.³,⁴ In the periorbital skin it arises from the matrix cells at the base of the eyelids and the eyebrows.⁵ Although it can be seen in patients from infancy to old age, it is far more common in the first 2 decades of life. Sixty percent of cases arise before the age of 10 years,⁶,⁷,⁸ and 75% occur in patients 20 years or younger.⁹ Some studies have reported little or no gender difference,¹⁰,¹¹ but most have demonstrated a clear female predominance,¹²,¹³,¹⁴,¹⁵ with a female to male ratio of 2:1 to 3:1.⁹,¹⁶,¹⁷ The most common site of occurrence is the head and neck (51.8%), followed by lesions on the extremities (37.7%) and trunk (10.5%)⁷,¹⁸ and other rare sites such as the middle ear.¹⁹ Malignant transformation is rare but has been described, with metastasis to regional lymph nodes, the lung, brain, bones, and visceral organs.⁹,²⁰,²¹ Familial cases have also been observed,¹⁸,²⁰,²² sometimes in association with systemic syndromes. Lesions are typically single, and multiple pilomatrixomas are rare.²³,²⁴,²⁵ When multiple lesions are seen it should raise suspicion for related systemic disorders such as myotonic dystrophy,²⁶ Churg-Strauss syndrome,²⁷ Gardner syndrome,²⁸ trisomy 9,²⁹ Rubinstein-Taybi syndrome,³⁰ xeroderma pigmentosum,³¹ and sarcoidosis.³²

Periocular pilomatrixoma is uncommon, but many cases have been described.¹,⁵,³⁰,³³,³⁴,³⁵,³⁶,³⁷,³⁸,³⁹,⁴⁰,⁴¹ In a series of 16 periocular cases, the mean age of patients at treatment was 17 years (range, 1-74 years),¹⁶ and there was a clear female predominance.