Pilomatrix carcinoma in a child

Pilomatrix carcinoma on the left side of the parotid region: A case report and review of the literature

Pilomatrix carcinoma (PC) is a rare neoplasm, particularly in the parotid region. Thus, it is easily misdiagnosed and an optimal treatment regimen has not yet been established. The present study reports the case of a 43-year-old female who presented with a PC of the parotid region and reviews the associated published literature. The patient underwent three surgical excisions prior to the tumor being completely removed, and was misdiagnosed four times prior to the correct diagnosis. Once the tumor was completely removed, the patient received radiation therapy (RT). At the 2-year follow-up, the patient remained free of local recurrence and metastasis. To the best of our knowledge, only 3 cases of PC on the parotid region have been reported. Although an optimal treatment regimen has not been established, surgery with wide margins is recommended, with RT and chemotherapy producing mixed results.

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.

Pilomatrix carcinoma: a case report and review of the literature

Pilomatrixoma is a common benign neoplasm of children and young adults with a female predilection. In contrast, its malignant counterpart, pilomatrix carcinoma is a rare neoplasm of older adults with a male preponderance. Pilomatrix carcinomas are locally aggressive with a tendency to recur. We report a case of a 44-year-old male who presented with an enlarging soft tissue tumor on the right upper back. Histology revealed an asymmetric, poorly circumscribed, lobulated neoplasm located deeply in the dermis with infiltration into the underlying subcutaneous tissue. The tumor was comprised of basaloid cells containing vesicular nuclei, prominent nucleoli, scant cytoplasm, and brisk mitotic activity. A focus of basaloid cells transitioning to shadow cells with central keratinized material and tumor necrosis was also present. The diagnosis of a pilomatrix carcinoma was rendered. Considering the infiltrative nature of this neoplasm with perineural and intramuscular invasion, the patient underwent 3 surgical excisions before it was completely removed.

Pilomatricomas in Turner syndrome

Pilomatricomas are benign, cutaneous tumors of the hair matrix cells, which present predominantly in childhood. Although usually an isolated finding, they have been described in association with several inherited conditions. We report a 10-year-old girl with Turner syndrome who has two pilomatricomas, including one giant tumor. In combination with a previous report of pilomatricoma in two patients with Turner syndrome, our observation indicates that it is likely a real, although uncommon, association of pilomatricomas with Turner syndrome exists. This apparent predisposition may be etiologically related to the abnormalities of hair-bearing skin observed in Turner syndrome. Doctors involved in the diagnosis and management of cutaneous masses in children should be aware of this association.

Pilomatrix carcinomas contain mutations in CTNNB1, the gene encoding beta-catenin

Mutations in beta-catenin are present in benign pilomatrixomas. beta-catenin is a downstream effector in the WNT-signalling pathway, acting as a signal for differentiation and proliferation. Mutations in CTNNB1, the gene encoding beta-catenin, are present in a wide variety of benign and malignant neoplasms. We examined beta-catenin in a series of pilomatrix carcinomas (15 cases) by using immunohistochemistry and DNA sequencing of exon 3 from CTNNB1, and compared these to a series of benign pilomatrixomas (13 cases). All 11 pilomatrix carcinomas available for examination showed nuclear localization of beta-catenin and mutations in exon 3 similar to those demonstrated in benign pilomatrixomas. Two of 11 pilomatrix carcinomas showed significant nuclear accumulation of p53, whereas this was absent in all 13 benign pilomatrixomas. Expression of nuclear cyclin D1 was similar in both benign pilomatrixomas and pilomatrix carcinomas. Clinical follow-up from the 15 malignant cases reported in this study and by others indicates that wide excision offers superior control of local recurrence, compared to simple excision. Immunohistochemical and molecular analysis of beta-catenin reveals that both pilomatrix carcinomas and benign pilomatrixomas harbour mutations in beta-catenin. This implies a common initial pathogenesis and is compatible with the proposition that pilomatrix carcinomas may at least on occasion arise from their benign counterparts.

Concurrent pilomatrix carcinoma and giant pilomatrixoma

A 52-year-old man presented with a large, fungating mass on the inner aspect of his left thigh and a smaller hard mass on the inner aspect of his left knee with normal overlying skin. Both lesions had first been noted by the patient 1 year previously and for the first 6 months had a similar appearance until the thigh mass rapidly increased in size and fungated. Pathology of the large thigh lesion showed pilomatrix carcinoma while that of the smaller knee lesion was typical of pilomatrixoma. The pilomatrix carcinoma was widely excised and there has been no evidence of recurrence or metastasis after 3 years. The clinical course of the thigh lesion suggested that pilomatrix carcinoma may arise from a pre-existing pilomatrixoma. On review of the literature, pilomatrix carcinoma of the lower limb may be more likely to metastasize than those on other sites.