Multiple familial pilomatricomas: a cutaneous marker for Gardner syndrome?

Head and neck pilomatricoma in the pediatric age group: a retrospective study and literature review

OBJECTIVE

To discuss the clinical course and management of pilomatricoma involving the head and neck in the pediatric age group and to review the literature.

METHODS

Retrospective analysis of the author's case files between the years of 1996 and 2000, revealed seven cases of head and neck pilomatricoma involving children. A literature review was employed to compare this study to others.

RESULTS

In all cases, the presenting sign was a superficially located rock-hard mass in the head and neck. The mean duration the mass was present at the initial otolaryngologic evaluation was 11 months. There was a total of seven patients of which five (71%) were female while two (29%) were male. Each patient presented with a single pilomatricoma. Five (71%) occurred in the neck while two (29%) occurred in the face. All were treated with surgical excision. There were no recurrences.

CONCLUSION

Pilomatricoma is a rare, benign, skin neoplasm that is superficially located and most commonly occurs in the head and neck, thus otolaryngologists should be aware of its clinical presentation. Although malignant transformation has been described, it is exceedingly rare. Diagnosis is usually suspected based on palpation of a superficial, rock-hard mass and confirmed by histopathologic examination. Since this neoplasm doesn't spontaneously regress, surgical excision is both curative and the treatment of choice. Recurrence is rare.

Two cases of multiple giant pilomatricoma

Pilomatricoma is a skin appendage tumor manifestating as a firm, solitary lesion of the face and upper extremity. It generally measures 0.5 to 3.0 cm in diameter and is typically found in young people. We report a 29-year-old male and a 13-year-old girl who developed three and two protruding masses, respectively. The size of each tumor was larger than 5 cm. The histologic appearance showed sharply demarcated tumor lobules composed of eosinophilic shadow cells and basaloid cells. We describe two unusual cases of multiple giant pilomatricomas and review the literature, emphasizing the number and size.

A common human skin tumour is caused by activating mutations in beta-catenin

WNT signalling orchestrates a number of developmental programs. In response to this stimulus, cytoplasmic beta-catenin (encoded by CTNNB1) is stabilized, enabling downstream transcriptional activation by members of the LEF/TCF family. One of the target genes for beta-catenin/TCF encodes c-MYC, explaining why constitutive activation of the WNT pathway can lead to cancer, particularly in the colon. Most colon cancers arise from mutations in the gene encoding adenomatous polyposis coli (APC), a protein required for ubiquitin-mediated degradation of beta-catenin, but a small percentage of colon and some other cancers harbour beta-catenin-stabilizing mutations. Recently, we discovered that transgenic mice expressing an activated beta-catenin are predisposed to developing skin tumours resembling pilomatricomas. Given that the skin of these adult mice also exhibits signs of de novo hair-follicle morphogenesis, we wondered whether human pilomatricomas might originate from hair matrix cells and whether they might possess beta-catenin-stabilizing mutations. Here, we explore the cell origin and aetiology of this common human skin tumour. We found nuclear LEF-1 in the dividing tumour cells, providing biochemical evidence that pilomatricomas are derived from hair matrix cells. At least 75% of these tumours possess mutations affecting the amino-terminal segment, normally involved in phosphorylation-dependent, ubiquitin-mediated degradation of the protein. This percentage of CTNNB1 mutations is greater than in all other human tumours examined thus far, and directly implicates beta-catenin/LEF misregulation as the major cause of hair matrix cell tumorigenesis in humans.