Pilomatrixoma
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Pubmed
Journal: Cell
December/27/1998
Abstract

An effector of intercellular adhesion, beta-catenin also functions in Wnt signaling, associating with Lef-1/Tcf DNA-binding proteins to form a transcription factor. We report that this pathway operates in keratinocytes and that mice expressing a stabilized beta-catenin controlled by an epidermal promoter undergo a process resembling de novo hair morphogenesis. The new follicles formed sebaceous glands and dermal papilla, normally established only in embryogenesis. As in embryologically initiated hair germs, transgenic follicles induce Lef-1, but follicles are disoriented and defective in sonic hedgehog polarization. Additionally, proliferation continues unchecked, resulting in two types of tumors also found in humans. Our findings suggest that transient beta-catenin stabilization may be a key player in the long-sought epidermal signal leading to hair development and implicate aberrant beta-catenin activation in hair tumors.

Pubmed
Journal: Nature genetics
April/25/1999
Abstract

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.

Pubmed
Pubmed
Journal: Plastic and reconstructive surgery
January/5/2004
Abstract

Pilomatrixoma, also known as calcifying epithelioma of Malherbe, is a benign skin neoplasm that arises from hair follicle matrix cells. Pilomatrixoma is a common skin neoplasm in the pediatric population that is often misdiagnosed as other skin conditions. This study reviews an 11-year experience at a tertiary children's hospital, examining the cause, clinical and histopathological presentation, management, and treatment outcomes of pilomatrixoma. A review of the pathology database at Children's Hospital Los Angeles revealed 346 pilomatrixomas excised from 336 patients between 1991 and 2001. The hospital charts, pathology records, and plastic surgery clinic charts were reviewed with respect to variables such as sex, age at the time of presentation, clinical and histopathological presentation, preoperative diagnosis, management, recurrence, and treatment outcome. The main presenting symptom was a hard, subcutaneous, slowly growing mass. The preoperative diagnosis was accurate and consistent with the pathological diagnosis of pilomatrixoma in only 100 cases (28.9 percent). This entity should be considered with other benign or malignant conditions in the clinical differential diagnosis of solitary firm skin nodules, especially those on the head, neck, or upper limbs. The diagnosis can generally be made with a clinical examination. Imaging studies are not required unless symptoms or the location of the lesion warrants such diagnostic assessments. The treatment of choice is surgical excision, and the recurrence rate is low.

Pubmed
Journal: Archives of otolaryngology--head & neck surgery
January/5/2004
Abstract

OBJECTIVE

To describe the clinical presentations and management of pilomatricoma, formerly known as pilomatrixoma, of the head and neck.

METHODS

Retrospective study.

METHODS

Tertiary care center.

METHODS

The study included 179 patients with a diagnosis of pilomatricoma of the head and neck.

METHODS

All patients underwent surgical excision for pilomatricoma of the head and neck between 1991 and 2002.

RESULTS

Pilomatricoma occurred at any age (mean age, 29.8 years); 45.3% of the cases occurred in patients younger than 18 years. The female-male ratio was 0.97:1. The average size of the lesion was 1 cm. The most common sites of occurrence were the neck (30.2%), cheeks (16.8%), scalp (16.2%), and brow and periorbital area (14.0%). Multiple occurrence was found in 1 case. Two of 179 tumors recurred after surgical excision.

CONCLUSIONS

Because preoperative diagnosis of pilomatricoma is usually incorrect, careful clinical examination and a high index of suspicion would result in a more accurate diagnosis. Complete surgical excision is the treatment of choice. Otolaryngologists should consider pilomatricoma in the differential diagnosis of neck masses.

Pubmed
Journal: American journal of clinical pathology
December/2/2003
Abstract

We studied the beta-catenin immunohistochemical profile in tumors expressing shadow cells: pilomatricoma, 10 cases; calcifying odontogenic cyst, 6 cases; and craniopharyngioma, 9 cases. There was strong membranous, cytoplasmic, and nuclear staining of the immature basaloid cells in all of these tumors. Shadow cells were negative in all tumors. It has been documented that rising levels of free beta-catenin drive the formation of complexes with T-cell factor/lymphoid enhancer factor (TCF-Lef) and up-regulate the wingless-Wnt cell-cell signals. The end result is an abnormality of beta-catenin degradation and, thus, a buildup of free beta-catenin in the cytoplasm and/or nucleus, resulting in the stimulation of cellular proliferation and/or inhibition of cell death. beta-Catenin seems to have an important role in the oncogenesis of these tumors. The similar pattern of keratinization in these tumors and the similar pattern of beta-catenin immunoreactivity in the cytoplasm and the nucleus are important findings. It seems that the activation of a common cellular pathway, namely Wnt-beta-catenin-TCF-Lef, has a role in the pathogenesis of these tumors. The latter could be related to their shared method of keratinization or shared dysfunction of the cellular adhesion complex leading to tumorigenesis.

Pubmed
Journal: Journal of the American Academy of Dermatology
August/30/1998
Abstract

BACKGROUND

Pilomatricomas have a wide variety of clinical characteristics and are often misdiagnosed. This can result in extensive surgery for an essentially benign condition.

OBJECTIVE

The purpose of this study was to define the clinical and histologic spectrum of these tumors to aid diagnosis.

METHODS

Two hundred nine cases were analyzed retrospectively with regard to age at presentation, site, size, and physical appearance.

RESULTS

Pilomatricomas appear at any age, with peak presentation bimodally in the first and sixth decade. Their most common site is the head and neck. Presentation is of a hard nodule, either deeply subcutaneous and invisible or superficial with possible erosion through the skin surface. This may lead to a false diagnosis of malignancy or of an epidermoid cyst. An association with myotonic dystrophy has been confirmed, as is the rare occurrence of malignant transformation.

CONCLUSIONS

Careful clinical examination and a high index of suspicion results in an accurate diagnosis, appropriate treatment, and the avoidance of unnecessarily extensive surgery.

Pubmed
Journal: Journal of dermatological science
June/1/2006
Abstract

BACKGROUND

beta-Catenin has been shown to play an important role in the formation of hair follicle-related tumors, including pilomatricomas. Several investigators have shown that beta-catenin gene mutation is observed in pilomatricomas. However, the relationship between the pattern of beta-catenin localization in the cell and beta-catenin gene mutation is still controversial.

OBJECTIVE

This work was performed to determine the frequency of beta-catenin nuclear localization in pilomatricoma, the relationship between the pattern of beta-catenin localization and beta-catenin mutation, and the involvement of APC mutation.

METHODS

Typical 32 pilomatricomas were examined for beta-catenin expression by immunostaining. Genomic DNA was extracted, amplified and sequenced from 23 pilomaticomas with nuclear beta-catenin staining and 4 pilomaticomas without nuclear beta-catenin staining. Mutations of beta-catenin gene were confirmed by subcloning assay and restriction endonuclease assay.

RESULTS

Using immunostaining, we found that 81% (26/32) of pilomatricomas displayed nuclear beta-catenin staining in basophilic cells. Sequence analysis revealed that 61% (14/23) contained mutations in exon 3 of beta-catenin. However, no mutations were detected in 4 pilomaticomas without beta-catenin nuclear staining. Detected mutations were adjacent to or abolished well-known regulatory phosphorylation sites of beta-catenin. APC gene mutations were not detected in 27 pilomatricomas with/without beta-catenin nuclear staining.

CONCLUSIONS

These results confirmed that beta-catenin mutation and its nuclear localization are frequent causes of Wnt signaling pathway activation and suggested that beta-catenin activation mutations contribute to tumorigenesis of pilomatricomas.

Pubmed
Journal: International journal of pediatric otorhinolaryngology
April/18/2001
Abstract

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.

CONCLUSIONS

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.

Authors
Pubmed
Journal: The American journal of pathology
September/21/2003
Abstract

The proliferation of keratinocytes in the hair follicle varies from slowly cycling, intermittently proliferating stem cells in the bulge to rapidly proliferating, transient cells in the bulb. To better understand the biological differences between these two compartments, we sought to identify differentially expressed genes using cDNA macroarray analysis. Cyclin D1 was one of 13 genes increased in the bulge compared to the bulb, and its differential expression was corroborated by quantitative real-time polymerase chain reaction (PCR) on the original samples. Using immunohistochemical staining, laser-capture microdissection (LCM) and quantitative real-time PCR, we localized cyclin D1 to the suprabasal cells of the telogen bulge and anagen outer root sheath (ORS). Surprisingly, cyclin D1, D2, and D3 were not detectable by immunohistochemistry in the rapidly proliferating hair-producing cells of the anagen bulb (matrix cells), while these cells were strongly positive for Ki-67 and retinoblastoma protein. In contrast, pilomatricoma, a tumor thought to be derived from matrix cells, was positive for cyclin D1, D2, and D3. Our results suggest that cyclin D1 may mediate the proliferation of stem cells in the bulge to more differentiated transient amplifying cells in the suprabasal ORS. In contrast, non-cyclin D1-proteins appear to control cell division of the highly proliferative bulb matrix cells. This non-cyclin D1-mediated proliferation may provide a protective mechanism against tumorigenesis, which is overridden in pilomatricomas. Our data also demonstrate that the combination of DNA macroarray, LCM and quantitative real-time PCR is a powerful approach for the study of gene expression in defined cell populations with limited starting material.

Pubmed
Journal: Pathology international
October/17/2001
Abstract

beta-Catenin, a multifunctional protein related to the adherens junction and to signal transduction, is a key molecule of cell proliferation, and it is central to epithelial architecture, regulating the polarity of cells and tissues. beta-Catenin stabilization may play a key role in epidermal signaling leading to hair development, and its aberrant activation may be implicated in formation of hair tumors. Several investigators have shown that pilomatricomas are frequently associated with beta-catenin mutation. In this study, we confirmed beta-catenin gene (CTNNB1) mutation in human pilomatricomas (100% frequency) from which adequate DNA could be obtained for gene analysis. A novel mutation, D32N, was found in one case of pilomatricoma. A preliminary immunohistological study revealed prominent beta-catenin staining in basophilic cells of pilomatricomas, especially in nuclei. Benign tumors which were considered to be derived from hair matrix or hair follicles, and other benign skin tumors, were also investigated. beta-Catenin mutations were not detected in any of the these tumors. These results seem to indicate that hair matrix cells are key players in hair development. Investigation into gene abnormalities of hair-follicle tumors may elucidate the cause of their neoplastic transformation, and may provide a suggestion for the mechanism of hair development.

Pubmed
Journal: American journal of medical genetics. Part A
June/26/2005
Abstract

MYH-associated polyposis (MAP) is a recently described autosomal recessive form of familial adenomatous polyposis (FAP) associated with susceptibility to colorectal carcinoma (CRC). MAP is caused by biallelic inactivating mutations of the MYH gene, a component of the base excision repair (BER) machinery, whose dysfunction leads to an increase in the rate of G > T transversions following DNA oxidative damage. MAP patients can present with either classic or attenuated polyposis. However, the MAP colonic and extracolonic phenotype has yet to be defined. We report on two siblings, born from consanguineous parents, who were found to be homozygotes for an MYH frameshift mutation. The propositus presented with a low number of colonic lesions and an early-onset CRC. Both siblings had a history of pilomatricomas, benign tumors derived from hair follicles, in childhood. The findings presented provide further evidence of phenotypic variability in MAP, and suggest that multiple pilomatricomas may be a useful cutaneous marker of MAP.

Pubmed
Journal: Archives of otolaryngology--head & neck surgery
January/2/2001
Abstract

BACKGROUND

Noninflammatory masses of the salivary gland region in children are extremely rare. Therefore, very few published individual and institution-based experiences exist.

METHODS

Retrospective chart review from 1990 through 1997.

METHODS

University-based children's hospital.

METHODS

Patients 18 years of age or younger with a tumor in the salivary gland region. Masses of infectious origin were excluded. Hemangiomas and lymphangiomas were tallied for relative incidences only.

RESULTS

Three hundred twenty-four consecutive cases of salivary gland masses were found: 192 hemangiomas (59.2%), 89 lymphangiomas (27.5%), and 43 (13.3%) solid masses. No significant difference was found between the age at presentation of the patients with benign solid tumors and the patients with malignant solid tumors (mean + SEM age, 7.2 + 0.7 years). Sixty-one percent of the masses were found in the parotid region; 18% were localized to the submandibular gland region; and the remaining 21% were located in a minor salivary gland site. The most common benign perisalivary masses were pilomatrixomas (20.9%), followed by pleomorphic adenomas (11.6%). The most common malignant masses were mucoepidermoid carcinomas (9.3%), followed by rhabdomyosarcomas (7.0%). Treatment was individualized to the disease. Twenty-two patients had adequate data for follow-up analysis (mean + SEM follow-up, 30.0 + 8.4 months). Four patients (18.2%) experienced recurrent or residual disease and were alive with disease at last follow-up, and 100% of our population demonstrated disease-specific survival at last follow-up.

CONCLUSIONS

Vascular lesions outnumber solid tumors of the salivary gland region. The most common salivary tumors were pleomorphic adenomas, followed by mucoepidermoid carcinomas. Although certain solid salivary masses may demonstrate locally aggressive behavior, the overall prognosis is favorable. Arch Otolaryngol Head Neck Surg. 2000;126:1435-1439

Pubmed
Journal: The British journal of dermatology
December/9/2001
Abstract

BACKGROUND

beta-catenin functions in signal transduction in the Wnt signalling pathway, which has recently been implicated in hair follicle (HF) morphogenesis. beta-catenin gene mutations affecting exon 3 have been reported in a high percentage of human pilomatrixomas. However, the expression pattern of beta-catenin in human HFs and pilomatrixomas has not been reported.

OBJECTIVE

To analyse immunohistochemically the expression pattern of beta-catenin in normal anagen HFs and in 40 human pilomatrixomas.

METHODS

In 11 of these tumours we also studied exon 3 beta-catenin gene mutations by polymerase chain reaction and direct sequencing. As these mutations have been related to a replication error (RER) phenotype in other tumour types, we explored whether or not this association also occurs in pilomatrixomas.

RESULTS

beta-catenin was expressed in the cell membranes of the outer and inner root sheaths and in matrix cells located at the base and periphery of the HF bulb. However, central matrix cells that differentiate into cortical cells, cortical and cuticular cells expressed beta-catenin in the nucleus, suggesting a role in signal transduction. In addition, some fibroblasts of the dermal papilla also showed nuclear expression of beta-catenin. All 40 analysed pilomatrixomas showed intense nuclear and cytoplasmic beta-catenin expression in proliferating matrix (basaloid) cells. In areas of maturation, transitional cells mainly showed cytoplasmic and membranous expression of beta-catenin, while only a few cells retained nuclear expression. Shadow or ghost cells did not show beta-catenin expression. Three of 11 tumours (26%) had beta-catenin mutations. All three had the same heterozygote mis-sense mutation: a G to T change affecting the first nucleotide at codon 32 (D32Y). None of the 11 tumours studied had a positive RER phenotype.

CONCLUSIONS

Present and previous studies suggest that the Wnt/beta-catenin/Tcf-Lef pathway is activated in normal matrix cells of the HF to induce differentiation to the hair shaft. Additionally, the beta-catenin mutation in matrix cells of the HF stabilizes beta-catenin protein, which translocates into the nucleus, where it activates of gene transcription together with lymphoid enhancer factor-1 producing pilomatrixoma. These mutations occur without an underlying defect in DNA mismatch repair.

Pubmed
Journal: Journal of pediatric surgery
October/26/2006
Abstract

OBJECTIVE

Pilomatrixoma is a common tumor of skin appendages in children. The aim of the study was to assess the accuracy of clinical diagnosis and factors contributing to misdiagnosis.

METHODS

A retrospective case note review of patients who had pilomatrixoma excised during a 5-year period in a tertiary referral children's hospital in the UK.

RESULTS

From 75 patients, 78 pilomatrixomata were excised. The diagnosis was achieved preoperatively in 46% of patients. Other diagnoses included sebaceous and dermoid cysts, foreign body reaction, calcification in lymph gland, and fat necrosis.

CONCLUSIONS

Factors contributing to misdiagnosis include cystic lesions with varying consistency, punctum-like appearance, atypical location, and absence of clinically recognizable calcification. Despite close excision, the recurrence rate is low.

Pubmed
Journal: Microscopy research and technique
January/16/2006
Abstract

Raman microspectroscopy was applied to analyze the changes in structural conformation and chemical composition of the mass of human skin pilomatrixoma (PMX). The normal skin dermis, collagen type I, and hydroxyapatite (HA) were used as control. The excised specimens from two patients diagnosed as a typical PMX were detected, in which one specimen was a soft mass, but the other was a hard mass with somewhat calcified deposits via histopathological examination. The Raman spectrum of normal skin dermis was found to be similar to the Raman spectrum of collagen type I, confirming that the collagen type I was a predominant component in normal skin dermis. The differences of Raman peak intensity between normal skin dermis and soft or hard PMX mass were obvious at 1,622-1,558, 1,400-1,230, 1,128, 1,000-850, 749, and 509 cm(-1). In particular, the peak at 1,665 cm(-1) assigned to amide I band shifted to 1,655 cm(-1) and the peak at 1,246 cm(-1) corresponding to amide III band was reduced in its intensity in hard PMX mass. The significant changes in collagen content and its structural conformation, the higher content of tryptophan, and disulfide formation in PMX masses were markedly evidenced. In addition, the shoulder and weak peak at 960 cm(-1) assigned to the stretching vibration of PO(4) (3-) of HA also appeared respectively in the Raman spectra of soft and hard PMX masses, suggesting the occurrence of calcification of HA in the PMX tissue, particularly in the hard PMX mass. The result indicates that the micro-Raman spectroscopy may provide a highly sensitive and specific method for identifying normal skin dermis and how it differs in chemical composition from different PMX tissues.

Pubmed
Journal: British journal of plastic surgery
August/11/1999
Abstract

The association of pilomatrixoma and myotonic dystrophy has been described in the past in 13 publications in the English literature. The association seems to involve the development of pilomatrixomata before signs of myotonic dystrophy. Myotonic dystrophy is the commonest adult dystrophy and is an autosomaldominant disease with a variable phenotypic penetrance. The disease is determined by a genetic locus on chromosome 19q and can be diagnosed using methods of DNA testing. We describe the 25th case of a patient with both conditions together with a review of the literature. To our knowledge, no other patient has had such a large number of histologically proven pilomatrixomata.

Pubmed
Journal: Archives of otolaryngology--head & neck surgery
November/30/1998
Abstract

OBJECTIVE

To describe the clinical presentations and discuss the guidelines for surgical management of pilomatrixoma involving the head and neck in children.

METHODS

Retrospective study.

METHODS

A tertiary care center.

METHODS

Thirty-three patients, with a mean age of 4.5 years, underwent surgical treatment for pilomatrixoma (n = 38) between 1989 and 1997.

METHODS

All patients were treated surgically. In 34 cases, a direct approach was used to achieve complete removal of the lesion with (n = 11) or without (n = 23) skin resection. In the remaining 4 cases, an indirect approach via a parotidectomylike incision was used.

RESULTS

In 88% of cases, the presenting symptom was a hard, slow-growing, subcutaneous tumor. The lesion was associated with pain and inflammation in 7 cases (18%) and abscess or ulceration in 4 cases (11%). Twenty-nine patients presented with single nodules and 4 presented with multiple occurrences. The lesions were located on the face (cheek, eyelid, or forehead) in 20 cases (53%), on the neck in 8 cases (21%), in the parotid region in 8 cases (21%), and on the scalp in 2 cases (5%).

CONCLUSIONS

Pilomatrixoma is a rare, benign skin tumor, but practitioners should be aware of its clinical features. Diagnosis is usually easy based on clinical findings, but computed tomographic scan is helpful, especially in cases involving tumors located in the parotid region. Spontaneous regression is never observed. Complete surgical excision, including the overlying skin, is the treatment of choice.

Pubmed
Journal: Journal of cutaneous pathology
June/7/2005
Abstract

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.

Pubmed
Journal: Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine
December/22/2005
Abstract

OBJECTIVE

The purpose of this series was to describe typical ultrasonographic features of 20 cases of pilomatricoma and to improve its diagnostic rate with the use of an ultrasonographic approach.

METHODS

For 20 pilomatricomas in 19 patients with preoperative ultrasonography from 1995 to 2004, we reviewed age, sex, symptoms, duration, referring clinician, and tumor sites. The ultrasonographic findings were retrospectively analyzed for tumor location, shape, size, margin, echo texture, echogenicity, presence, amount, and shape of calcification, presence of a hypoechoic rim, and Doppler flow pattern.

RESULTS

The mean age of the 19 patients was 6.9 years (range, 1-21 years), and the female-male ratio was 1.1:1. Patients had a painful palpable mass in 10 cases (50%). Nine lesions occurred in the neck, 5 in the cheek, 2 in the preauricular region, and 4 in the extremity. All tumors were located in the subcutaneous layer. The mean size of the tumors was 13.4 mm. Fourteen pilomatricomas (70%) appeared as well-defined oval masses. Tumors were heterogeneously hyperechoic in 80% of cases. All tumors had internal echogenic foci. A hypoechoic rim was seen in 17 cases (85%). Doppler flow signals were observed in the peripheral region in 14 cases (70%). A correct preoperative diagnosis was made in 33% on the basis of clinical findings and in 76% by ultrasonography.

CONCLUSIONS

Diagnosis of pilomatricoma should be considered when a well-defined mass with inner echogenic foci and a peripheral hypoechoic rim or a completely echogenic mass with strong posterior acoustic shadowing in the subcutaneous layer of the head, neck, or extremity is found on ultrasonography.

Pubmed
Journal: Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery
December/18/2001
Abstract

OBJECTIVE

Pilomatrixomas are benign skin neoplasms of hair follicle origin. They are one of the most common superficial masses of the head and neck excised in children. Although the entity has been well studied in the literature, few studies have been undertaken to evaluate the clinical characteristics of head and neck pilomatrixomas specifically in children. The purpose of this study was to review the clinical characteristics and management of children presenting with pilomatrixomas of the head and neck at a large tertiary care pediatric hospital.

METHODS

A retrospective chart review was performed of all patients with histologically confirmed pilomatrixoma of the head and neck excised during a 6-year period (1992-1997) at the Children's Hospital of Philadelphia.

RESULTS

Ninety-one cases of pilomatrixoma were confirmed in 86 patients. The age range was 5 months to 17 years. The median age at time of excision was 6.0 years. The most common sites of occurrence were the cheek (36%), neck (20%), periorbital region (14%), and scalp (9%). The male to female ratio was 1:1.5. Multiple lesions were found in 8.2% of patients. Surgical excision was curative in all cases.

CONCLUSIONS

Pilomatrixoma is a cutaneous neoplasm that is one of most common causes of superficial head and neck masses in children. Although the presurgical diagnosis may be difficult in some cases, pilomatrixoma must be kept in the differential of superficial head and neck masses in children. Surgical excision is almost always curative.

Pubmed
Journal: The American Journal of dermatopathology
March/28/2005
Abstract

We investigated the expression of CD10 by an immunohistochemical method in 51 basal cell carcinomas (BCCs), eight pilomatricomas, five trichoblastomas, two trichofolliculomas, three sebaceomas, five sebaceous carcinomas, ten syringomas, two spiradenomas, ten poromas, four porocarcinomas, one eccrine duct carcinoma (not otherwise specified, NOS), six mixed tumors of apocrine origin, and nine squamous cell carcinomas (SCCs). We detected strong expression of CD10 in tumor cells of BCC (86%), and found that the smaller the number of positive tumor cells, the larger the number of positive stromal cells, in particular in sclerosing BCCs. Spearman's rank correlation test revealed a significant negative correlation in BCCs between the expression of CD10 in tumor cells and that in stromal cells (P = 0.001). In all pilomatricomas (100%) and in four trichoblastomas (80%), strong expression was also detected in tumor cells. There was no detectable expression in trichofolliculomas. One sebaceoma (33%) and two sebaceous carcinomas (40%) expressed CD10 in a similar fashion to BCCs. All tumors of eccrine gland origin, including syringoma, spiradenoma, poroma, porocarcinoma, and eccrine duct carcinoma (NOS), did not express CD10. Five mixed tumors (83%) were immunopositive. In SCC, CD10 was overexpressed only in the stromal cells. These findings support the hypothesis that BCC is derived from the folliculo-sebaceous apocrine unit, especially having the same origin as trichoblastoma and pilomatricoma. CD10 might be an indicator of tumor invasiveness if it is expressed in stromal cells, while it might be a marker of follicular differentiation if it is expressed in the actual tumor cells of cutaneous epithelial neoplasms.

Pubmed
Journal: Cancer
May/27/1996
Abstract

BACKGROUND

The malignant variant of pilomatrixoma is pilomatrix carcinoma, a low-grade, malignant lesion with a tendency to recur. Only three cases with visceral metastases, occurring some years after primary diagnosis, have been reported.

METHODS

A case of metastatic pilomatrix carcinoma of the neck in a patient, age 50 years, is presented.

RESULTS

Histologic examination of the cutaneous lesion showed a dense infiltrate of basaloid cells, an abrupt transition to shadow cells, and central necrosis. Two months after primary diagnosis, pulmonary and brain metastases developed. Despite chemotherapy and irradiation, the patient died a widespread disease 18 months after the primary diagnosis. An autopsy confirmed the diagnosis of pilomatrix carcinoma with metastases to several organs including the heart, lung, brain, liver, pancreas, kidney, adrenal gland, gastric and colorectal submucosa, skin, and bone.

CONCLUSIONS

Pilomatrix carcinoma is very rare and usually behaves like a low-grade, malignant lesion with a tendency to recur. This patient's tumor is unique because of its highly aggressive behavior and visceral metastases.

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