Pilomatrixoma D23.L

A. Painted sherbet 1880

Frequent, mostly solitary, rarely multiple, benign adnexal tumor originating from the hair matrix cells and calcifying early with hair follicle differentiation.

Controversial. Associations with Bcl-2 expression, as well as mutations in the CTNNB1 gene and dysregulation of beta-catenin/LEF expression, are under discussion.

Solitary, rarely multiple, painless, hard to bony, sharply defined, 0.5-3 cm in diameter (rarely larger - giant pilomatricoma), subcutaneous, skin-colored, reddened or reddish-brown nodule. Frequently calcifications, more rarely ossifications. Very slowly progressive, usually growing over several years.

Rare clinical variants are.

• anetodermic variant (skin over the tumor appears atrophic)
• pigmented pilomatrixoma
• ulcerated pilomatrixoma
• giant forms (up to 20 cm in size)
• multiple pilomatrixomas possibly in association with Turner syndrome, trisomy 9, Gardner syndrome
• multiple familial pilomatrixomas

Lobular tumor in the middle to deep dermis, in some places also extending into the subcutis. The appearance depends on age (regressive changes). Basophilic cells with hyperchromatic nuclei and some (sometimes numerous) mitoses are localized in the outer layer. Centrally, there are usually eosinophilic cells (shadow cells). Older tumors show extensive zones of necrosis and metaplastic calcifications. Regressive tumors are surrounded by dense granulation tissue.

Clinic is characteristic, histology is conclusive.

1. Fernandes R et al (2003) Giant pilomatricoma (Epithelioma of Melherbe): Report of a case and review of literature. J Oral Maxillofac Surgery 61: 634-636
2. Fetil E et al (2002) Multiple pilomatricoma with perforation. Int J Dermatol 41: 892-893
3. Grabczynska SA et al (2002) Case 3: Multiple familial pilomatrixoma. Clin Exp Dermatol 27: 343-344
4. Gromiko N (1927) On the knowledge of the malignant transformation of the calcified skin epithelioma. Arch Catholic Anat 265: 103-116
5. Haferkamp B et al (1999) Pilomatrix carcinoma in an unusual localization. dermatologist 50: 355-359
6. Hardisson D et al (2001) Pilomatrix carcinoma: a clinicopathologic study of six cases and review of the literature. At J Dermatopathol 23: 394-401
7. King IC et al (2015) Multiple familial pilomatrixomas in three generations: an unusual clinical picture. Pediatric dermatol 32: 97-101
8. Malherbe A, Chenantais J (1880) Note sur l'épitheliome calcifié des glandes sébacées. Prog Med 8: 826-828
9. Robinson AJ et al (2016) Multiple familial pilomatrixomas in the absence of other clinical features: a case of familial benign pilomatrixoma. Australas J Dermatol 57:75-76
10. Simon RS, Sanchez-Yus E (2002) Multinodular pilomatrixoma. Dermatology 204: 80-81
11. Wang J et al (2002) Pilomatrixoma: clinicopathologic study of 51 cases with emphasis on cytologic features. Diagn Cytopathol 27: 167-172
12. Zamecnik M (2000) Cell death in pilomatricoma. J Cutan Catholic 27: 100