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PubMed1995

[Pilomatrixoma of the auricle. Differential diagnosis with carcinoma pilomatrixoma].

A 34 year-old man, with a two centimeter diameter quickly growing nodule on the auricular pavillion is presented. After mass excision the histologic diagnosis of pilomatrixoma was made. Pilomatrixoma is a rare benign tumor arising on the hair matrix. The differential diagnosis include pilomatrix carcinoma, a locally and recurrent aggressive tumor capable to make pulmonary metastasis. A review of the literature is included, with emphasis on the clinical and histopathological aspects and the therapeutic attitude.

Adult↗

PubMed1999

Expression of human hair keratin basic 1 in pilomatrixoma. A study of 128 cases.

Hard keratins are expressed in normal hair and nails, and are characterized by a higher cysteine content than cytokeratins. Previous studies have suggested a coexpression of hard keratins and cytokeratins in pilomatrixoma, a benign follicular tumour which could originate from the hair matrix. Human hair keratin basic 1 (hHb1) is a newly characterized hair keratin which is expressed specifically by cortical cells of the normal hair shaft. A preliminary study has suggested that hHb1 could be expressed in pilomatrixoma. In order to confirm this hypothesis, we have studied a series of 128 pilomatrixomas by in situ hybridization, using a 35S-labelled hHb1-specific probe. The anti-sense probe was used as a negative control. Among these pilomatrixomas, six were early cases, 60 were classified into the intermediate stage (either fully developed or early regressive cases) and 62 were late regressive tumours made of shadow cells only. Forty-seven tumours showed hHb1 expression (37%), all being intermediate stage pilomatrixomas. The areas positively stained by the probe were band-like structures made of transitional cells only, which were very close to cells showing tricholemmal keratinization features. Neither the basophilic matrix cells nor the shadow cells expressed hHb1. Our results suggest that pilomatrixomas can differentiate towards cortical cells during their maturation process, as this keratin is specifically expressed in the cortex of the normal hair shaft. These data are consistent with previous studies which showed the expression of a hard keratin group in transitional cells by immunohistochemistry. The histogenesis of basophilic cells of pilomatrixoma is controversial, but it is likely that transitional cells represent an equivalent of the hair cortex.

Adolescent↗

PubMed2001

Pilomatrixoma of the head and neck in children.

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. STUDY DESIGN: 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. CONCLUSION: 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.

Adolescent↗

PubMed2001

beta-catenin expression in pilomatrixomas. Relationship with beta-catenin gene mutations and comparison with beta-catenin expression in normal hair follicles.

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. OBJECTIVES: 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.

Adolescent↗

PubMed1998

[Pilomatrixoma often not identified as such].

OBJECTIVE: To inventory incidence, diagnosis and treatment of pilomatrixoma. DESIGN: Retrospective. METHOD: Patients treated in the period 1984-1996 in the department of Surgery of the Medical Spectrum Twente, Enschede for a pilomatrixoma were traced via the Dutch Automatic Morbid-Anatomical Records Office (PALGA). Data were collected by status study. Also, the patients or their parents were interviewed by telephone about recurrences. RESULTS: Forty-eight patients with 54 pilomatrixomas had been treated. The ages varied from 2 to 77 years, 14 patients were younger than 14 years. The correct diagnosis had been made preoperatively in 11 patients (20%) in four of whom (7%) the manifestation was not the first one. In many cases (69%), the condition was mistaken for an atheromatous cyst, in children as well (in 47% of the cases). The pilomatrixoma was localized in the head and neck area 25 times, in eight of these in the parotid region. Owing to incorrect interpretation of the abnormality, three children with a pilomatrixoma in the head and neck area underwent a more radical operation than necessary. CONCLUSION: The clinical diagnosis was frequently missed. In cutaneous tumours occurring in children or localized in the head and neck area the diagnosis of pilomatrixoma should be considered.

Adolescent↗

PubMed2001

Head and neck pilomatrixoma in children.

OBJECTIVE: To provide a review of the current information on the etiology, clinical presentation, management, and outcome of pilomatrixoma of the head and neck in children. DESIGN: Retrospective review. SETTING: A tertiary care pediatric center. PATIENTS: Fifty-one pediatric patients with a diagnosis of pilomatrixoma of the head and neck. INTERVENTION: All patients underwent excision of pilomatrixoma from January 1997 to March 1999. A total of 55 tumors were studied. RESULTS: A preponderance of girls (n = 36; 71%) presented with this condition. The average age at diagnosis was 5.7 years, and the average size of the lesion was 1 cm. The skin of the cheek and the periorbital area were the most commonly involved sites. Only 27 lesions (49%) had a correct preoperative diagnosis. Two (4%) of 55 tumors recurred after complete surgical excision. MAIN OUTCOME MEASURES: The age and sex of the patient, preoperative diagnosis, time elapsed before diagnosis, site and size of the tumor, length of follow-up, presence of multiple or previous pilomatrixomas, and recurrence. CONCLUSIONS: Preoperative diagnosis may be improved with increased awareness of pilomatrixoma, a common, benign skin tumor in children. Clinical findings will aid in an accurate diagnosis. Recurrence after complete local excision is rare.

Adolescent↗

PubMed2002

Pilomatrixoma: clinicopathologic study of 51 cases with emphasis on cytologic features.

The clinical and pathologic features of 51 cases of pilomatrixoma found in our archives from 1990-1999 were reviewed, with emphasis on the cytopathologic features of the 22 cases that were sampled by fine-needle aspiration (FNA) biopsy prior to excision. Although uncommon, almost 20% of the pilomatrixomas in this series occurred in adults over age 30. Of the commonly reported features, the presence of basaloid cells and ghost cells in FNA smears, associated with a cutaneous location of the lesion, was sufficient for a confident cytologic diagnosis of pilomatrixoma. The presence of foreign body-type giant cells, nucleated squamous cells, and calcification, alone or in combination, was less specific, but supported a diagnosis of pilomatrixoma. Although infrequently reported, prominent nucleoli in basaloid cells and smears containing refractile keratin clumps were very useful clues in the diagnosis of pilomatrixoma. Finally, the routine use of cell blocks is recommended because in many of the cases presented ghost cells were fragmented or obscured in smears, but were more readily identified in cell block sections.

Adolescent↗

PubMedDate not supplied

Use of ultrasonography in the diagnosis of childhood pilomatrixoma.

Pilomatrixomas are relatively common childhood tumors that usually occur in the head and neck region. The clinical diagnosis of these lesions may be difficult, especially if the examining physician is unfamiliar with them. Excision is usually recommended, as a foreign body reaction due to calcification of the lesion may occur and cause a vigorous inflammatory response with risk of scarring. A retrospective study was carried out by examining the preoperative ultrasound scans of 28 suspected pilomatrixomas in 25 children. The findings on sonography were correlated with the histologic results in 19 cases (18 pilomatrixomas and one ruptured epidermoid cyst). In the majority of patients, sonography either correctly supported or excluded the clinical diagnosis of pilomatrixoma and contributed to appropriate preoperative assessment and subsequent management of the lesion. We therefore found sonography of suspected pilomatrixomas in children to be a useful and noninvasive procedure, offering a significant improvement in the accurate diagnosis of these lesions.

Adolescent↗

PubMed1997

Cell renewal, cell differentiation and programmed cell death (apoptosis) in pilomatrixoma.

Pilomatrixoma is a benign tumour of the cutaneous adnexa. Histologically, pilomatrixoma comprises masses of immature basophilic cells, small numbers of polygonal squamoid cells, few transitional cells, and clusters of 'shadow cells'. The mechanism leading to the formation of shadow cells is still unknown. Skin biopsy specimens of pilomatrixoma (n = 15) were studied histologically, immunohistologically, and by applying the in situ end-labelling technique. The basal layer of the basophilic cells induced most of the proliferating cells with high expression of bcl-2 and cytokeratin 19. The overlying basophilic cells showed a negligible mitotic activity, a high significant accumulation of p53 protein, and a heterogeneous, but progressive loss of bcl-2 and cytokeratin 19. They developed either into squamoid cells or into transitional cells. The squamoid cells were characterized as differentiated cells resembling mature keratinocytes of stratified mucosa. The transitional cells could be shown to represent apoptotic cells proceeding to shadow cells. The data suggest that apoptosis is the main mechanism leading to the development of the dead shadow cells and is most probably responsible for the banal biological behaviour of pilomatrixoma. Apart from that, pilomatrixoma represents a suitable biological model to study apoptosis in humans.

Apoptosis↗

PubMed1996

Fine needle aspiration (FNA) cytology of pilomatrixoma.

FNA smears from five histologically confirmed cases of pilomatrixoma were reviewed to delineate the cytological features helpful in diagnosis. A combination of basaloid cells, ghost cells and foreign body giant cells appeared to be necessary in FNA smear for a confident cytodiagnosis of pilomatrixoma. Presence of naked nuclei, nucleated squamous cells and calcification were additional features in favour of the diagnosis. Another 10 cases with initial cytodiagnosis of pilomatrixoma or benign skin appendage tumour were reviewed. Using the above criteria, diagnosis of pilomatrixoma was easy in five cases. One case was problematical due to presence of atypical squamous cells. Initially the cytological features were most commonly confused with epidermal inclusion cyst, giant cell lesion or a squamous cell carcinoma. The main reasons for erroneous diagnosis were lack of awareness of cytological features, predominance of one component over the others, and non-representative FNA smears. Atypia in nucleated squamous cells, and misinterpretation of basaloid cells as malignant can lead to diagnostic dilemma. Adequate clinical data are also necessary.

Adolescent↗

PubMed1999

Pilomatrixoma of the eyelids and eyebrows in children and adolescents.

PURPOSE: To review the clinical features of pilomatrixomas of the eyelids and eyebrows in children and adolescents. METHODS: The authors reviewed the medical records of 95 patients, all of whom were 20 years old or younger and had the histopathologic diagnosis of pilomatrixoma made from 1976 through 1995. Special attention was given to that subgroup of patients with tumors involving the eyelids and eyebrows. Data analyzed included age at diagnosis, patient sex, location and size of tumor, preoperative diagnosis, and clinical description of tumor. RESULTS: Eleven (12%) of 95 patients had lesions involving the eyelid or eyebrow. Six of those patients (55%) were female. Eight patients (73%) were 10 years old or younger, and three were 11 to 20 years old. The tumor occurred on the upper lid or in the brow in eight patients, the lower eyelid in two patients, and the medial canthus in one patient. Tumor diameter was 1 cm or less in all 11 patients. Pilomatrixoma was included in the preoperative differential diagnosis in only four of the 11 patients. The most common misdiagnoses were epidermoid and dermoid cyst. Three patients had pink or blue discoloration of the overlying skin, two had visible yellow-white patches in the tumor, and two had dilated vessels on the tumor surface. CONCLUSIONS: Pilomatrixoma is an uncommon tumor that can occur on the eyelids and in the brow region of children and adolescents. It is commonly misdiagnosed preoperatively as an epidermoid or dermoid cyst. Distinctive clinical features, however, suggest the correct diagnosis.

Adolescent↗

PubMed1999

Two cases of pilomatrixoma in Turner's syndrome.

Multiple and familial cases of pilomatrixomas have been reported in myotonic dystrophy. We report 2 cases of pilomatrixoma in Turner's syndrome. Between 5 and 19 years of age, 1 patient developed 6 pilomatrixomas including atypical occurrences on the chest and the posterior aspect of the leg. This is the first report of multiple pilomatrixomas in Turner's syndrome.

Adolescent↗

PubMedDate not supplied

Fine needle aspiration diagnosis of pilomatrixoma. A case report.

BACKGROUND: Fine needle aspiration (FNA) diagnosis of pilomatrixoma is rare. The cytologic presentation can be mistaken for squamous cell carcinoma because of high cellularity, high nuclear/cytoplasmic ratio and presence of anucleate squames. CASE: A 25-year-old male presented to Cook County Hospital with a slowly enlarging neck mass of three months' duration. FNA was interpreted as consisted with pilomatrixoma. Subsequently the patient had the mass removed. Histology confirmed the diagnosis of pilomatrixoma. CONCLUSION: The wide range of cell differentiation in conjunction with pertinent clinical findings, absence of nuclear atypia, tumor diathesis, mitotic figures and awareness of the entity lead to the correct diagnosis of pilomatrixoma.

Adult↗

PubMed1984

Pilomatrixoma of the head and neck.

Pilomatrixoma is an uncommon neoplasm which occurs most frequently in the head and neck region. It usually presents as a slowly growing dermal or subcutaneous mass. Unfamiliarity with this lesion may lead the physician to mistake it for more common infectious or neoplastic processes. Most pilomatrixomas are benign and are adequately treated by local excision. Since a spectrum of clinical and histologic aggressiveness (pilomatrixoma carcinoma) has been noted in some lesions, a more aggressive surgical approach for such tumors is recommended. Two patients with pilomatrixoma are presented to emphasize the diagnostic confusion that can occur.

Aged↗

PubMed1985

Pilomatrixoma of the head and neck in children.

Pilomatrixoma, also known as calcifying epithelioma of Malherbe, is a benign tumor of hair cell origin. It is an unusual, but not particularly rare, tumor. Fifty percent or more of pilomatrixomas occur in the head and neck, and 40% occur in patients under 10 years of age. Pilomatrixomas may be mistaken for cysts, calcified lymph nodes, calcified hematomas or hemangiomas, or parotid gland tumors. We describe our experience with 15 children, 1 1/2-12 years of age, in whom we have excised pilomatrixomas from the head and neck.

Child↗

PubMed1988

Cytokeratin analysis of pilomatrixoma: changes in cytokeratin-type expression during differentiation.

The various structural components of pilomatrixoma (calcifying epithelioma of Malherbe) were studied for the expression of hair-specific (trichocytic) cytokeratins as well as epithelial cytokeratins, using immunoperoxidase and immunofluorescence microscopy of frozen sections as well as two-dimensional gel electrophoresis and immunoblotting. Trichocyte-type cytokeratins were detected in only a minor subpopulation of basophilic cells but more prominently in most "transitional" cells as well as in "shadow" cells. In contrast, antibodies against certain epithelial cytokeratins (including antibody KA1 against cytokeratins of stratified squamous epithelia and antibodies against cytokeratin 19) revealed an extensive but heterogeneous staining of basophilic cells. In regions of squamoid cells, epithelial cytokeratins in an unusual pattern were found. An antibody against vimentin was negative on pilomatrixoma cells. An antibody against desmoplakins decorated true desmosomes in basophilic and transitional cells. Biochemically, trichocytic cytokeratin polypeptides as well as epithelial cytokeratins 5, 6, 14, 16, 17, and 19 were positively detected. These results provide evidence in support of the notion of a trichocytic differentiation and probably derivation of pilomatrixoma. According to the cytokeratin expression patterns the majority of pilomatrixoma cells resemble the normal hair cortex lineage but some enter a pathway of squamous cell differentiation.

Adult↗

PubMedDate not supplied

Fine needle aspiration diagnosis of pilomatrixoma. A monomorphic population of basaloid cells with squamous differentiation not to be mistaken for carcinoma.

In a case of pilomatrixoma, an initial fine needle aspiration (FNA) biopsy of a skin lesion yielded only a monomorphic population of mitotically active basaloid cells with squamous differentiation, without anucleated ghost cells, chronic inflammatory cells or foreign-body giant cells. These findings suggested a metastatic squamous-cell carcinoma or a malignant tumor of adnexal skin. The correct diagnosis was made by repeat FNA, which yielded the basaloid cells and ghost cells characteristics of pilomatrixoma; the FNA diagnosis was confirmed by subsequent excisional biopsy. This case demonstrates that pilomatrixoma should be considered in the differential diagnosis of skin aspirates that contain a dominant population of basaloid cells. The differentiation of pilomatrixoma from malignant lesions of the head and neck region is discussed.

Biopsy, Needle↗

PubMed1998

Pilomatrixoma of the head and neck in children: a study of 38 cases and a review of the literature.

OBJECTIVES: To describe the clinical presentations and discuss the guidelines for surgical management of pilomatrixoma involving the head and neck in children. DESIGN: Retrospective study. SETTING: A tertiary care center. PATIENTS: Thirty-three patients, with a mean age of 4.5 years, underwent surgical treatment for pilomatrixoma (n = 38) between 1989 and 1997. INTERVENTION: 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.

Adolescent↗