Pilomatrixoma in a patient with bilateral retinoblastoma

Pilomatrixoma: A Comprehensive Review of the Literature

INTRODUCTION

Pilomatrixoma, also known as calcifying epithelioma of Malherbe, is a superficial benign skin tumor that arises from hair follicle matrix cells. Although pilomatrixomas are well-recognized lesions, clinically they are frequently misdiagnosed as other skin conditions. By reviewing all the literature over the past 10 years, the aims of this article are to analyze the cause, clinical presentation, management, and outcome of pilomatrixoma among children and adults to gain a more complete understanding of this lesion in today's clinical context.

METHODS

A MEDLINE and EMBASE search was conducted from January 2005 to February 2015 using a combination of the terms: "child," "childhood," "adult," and keywords: "pilomatrixoma," "pilomatricoma," and "calcifying epithelioma of Malherbe." A total of 150 articles were reviewed.

RESULTS

The lesions occurred most commonly in the first and second decades (mean age 16 years and 7 months). The commonest presentation was of an asymptomatic, firm, slowly growing, mobile nodule. Only 16% were accurately diagnosed on clinical examination. Imaging in the form of ultrasound, computed tomography, and magnetic resonance imaging has been reported. Pathological diagnosis was achieved through incision, punch, and shave biopsies. Pathological findings are discussed and summarized in this review.

CONCLUSION

Pilomatrixomas are thought to arise from mutation in the Wnt pathway and has been linked to several genetic conditions. It is commonly misdiagnosed preoperatively; however, with better awareness of the lesion, it can be appropriately treated while avoiding unnecessary diagnostic tests. Complete surgical excision with clear margins is almost always curative.

Pilomatrix carcinoma: 13 new cases and review of the literature with emphasis on predictors of metastasis

BACKGROUND

Pilomatrix carcinoma is a rare cutaneous tumor derived from follicular matrix cells with few cases documented in the literature.

OBJECTIVE

We sought to better characterize this tumor by analyzing its epidemiologic, clinical, and histopathologic features in 13 new cases and by reviewing the literature.

METHODS

All cases of pilomatrix carcinoma from a large regional dermatopathology practice were identified and analyzed by chart review for clinical and histopathologic characteristics. Similar characteristics were compiled from an additional 123 cases in the English-language literature. Cox proportional hazards regression models were used to determine risk factors associated with the development of metastasis for all identified metastatic tumors.

RESULTS

Our 13 tumors were most common in middle-aged to older white men and presented mostly on the head/neck. Histopathologically, tumors were asymmetric, were poorly circumscribed, were composed of basaloid and "ghost" cells, had frequent atypical mitoses, and had infrequent lymphovascular invasion. Wide excision was considered the most definitive treatment modality, but local recurrence was common. When analyzing all reported cases of metastasis using statistics, metastasis was significantly associated (hazard ratio 3.45, P < .0413) with local tumor recurrence.

LIMITATIONS

The retrospective, single-center design and the reliance on electronic medical records are limitations.

CONCLUSIONS

This study helps better characterize pilomatrix carcinoma and identifies potential predictors of metastasis.