Pilomatrixoma of the head and neck in children

Pilomatrixoma of the Arm: A Case Report and Review of Literature

Pilomatrixoma (PMX), also known as calcifying epithelioma of Malherbe, is a rare benign neoplasm that arises from the hair matrix cells, commonly in the head, neck, and upper trunk regions, infrequently affecting upper and lower extremities. It has to two peaks of presentation: under 20 years of age or between 50 and 65 years of age, slightly more common in females. The neoplasm exhibits diverse clinical manifestations and is frequently subject to misdiagnosis with alternative dermatological diseases. We present an atypical case of PMX affecting the upper extremity of a 62-year-old female patient. Surgical removal of the affected tissue under local anesthesia was performed, and subsequent histopathological analysis confirmed the presence of PMX. Based on the literature search we performed, we found out that this pathology is underreported in Jordan, with only one study published describing this tumor in the maxillofacial region. Physicians should be aware of this condition and its different presentations to include it in the differential diagnosis of suspected cases to provide the appropriate management and follow-up.

Cytological Diagnosis of Pilomatrixoma and its Diagnostic Pitfalls

Background

Pilomatrixoma (PMX) is a relatively uncommon benign cutaneous neoplasm arising from skin adnexa. It presents as a subcutaneous asymptomatic nodule mostly in the head and neck region and is frequently misdiagnosed by the clinicians. Although easily diagnosed on histopathology, the cytologic features of PMX are less distinctive, depending on the stage and evolution of disease and may mimic other benign or even malignant lesions.

Aim

To study the cyto-morphological features of this uncommon neoplasm and identify its potential diagnostic pitfalls on fine needle aspiration cytology (FNAC).

Material and Methods

Archival records of histopathologically diagnosed Pilomatrixoma were analyzed during study period of 2.5 years. Clinical diagnosis, preoperative FNA characteristics, and histopathological details were studied in each case. Cytologic pitfalls resulting in misdiagnosis of PMX cases on FNAC were evaluated in discordant cases.

Results

The series showed male preponderance, with head and neck being the commonest site. Out of 21 histopathologically proven cases of PMX, cytological correlation was available in 18 cases. A correct cytologic diagnosis of PMX/adnexal tumor was rendered in 13 cases. Erroneous diagnosis was given in 5 cases mainly because of the predominance of one component over the other or non-representative-aspirated material.

Conclusion

The present study highlights the importance of careful screening of FNAC smears keeping in mind the variability in the relevant cytologic features of PMX and creates awareness about the lesions that can mimic Pilomatrixoma resulting in diagnostic dilemma.

Cytomorphological spectrum of pilomatricoma - A series of 28 cases

BACKGROUND

Pilomatricoma is a benign tumour that originates in the outer sheath of the hair follicle root. The clinical diagnosis of this rare entity is often missed, possibly due to a lack of awareness. Its characteristic cytomorphological features are sheets of ghost cells, basaloid cells, calcification and foreign body giant cell reaction. However, the above features may not all be present in all cases, rendering cytological diagnosis difficult.

MATERIALS AND METHODS

This retrospective study included all cases of pilomatricoma diagnosed on fine needle aspiration over a period of 4 years. The histopathological diagnosis was retrieved for the cases wherever possible. A detailed histopathological and cytological evaluation was performed for the various components-basaloid cells, ghost cells, calcified debris, foreign body giant cells, bare nuclei, neutrophils, and macrophages-and they were graded on a scale of 0 to 3+.

RESULTS

The 28 cases included 8 female and 20 male patients with a mean age of 34.6 years. Most cases (22 cases; 78.6%) were located in the head and neck, with the scalp being the most common site. Twenty-five cases were cytologically diagnosed as pilomatricoma based on a variable admixture of the various components-nests of basaloid cells, ghost cells, foreign body giant cell reaction, calcified debris and viable squamous cells. However, in two cases which showed an absence of basaloid cells, a differential diagnosis of epidermal inclusion cyst was also included. Another case showed a predominance of basaloid cells with a paucity of ghost cells, so a differential diagnosis of adnexal tumour was also included. Among all the cytological parameters, sheets of ghost cells followed by nests of basaloid cells and foreign body giant cell reaction had the highest sensitivity in the cytological diagnosis of pilomatricoma.

CONCLUSION

The presence of sheets of ghost cells is the most sensitive parameter for the cytological diagnosis of pilomatricoma. It is important that pilomatricoma should be considered in the differential diagnosis of subcutaneous masses, particularly in the head and neck region.

Commonly Misdiagnosed Facial Lesion: Pilomatricoma

Pilomatricoma, also known as Pilamatrixoma or Malherbe's calcifying epithelioma, is a benign skin tumour with a bimodal age distribution between the paediatric and elderly age groups. Although it was previously thought to be rare, recent studies have revealed that it is quite common. Typically, pilomatricoma is diagnosed following histopathological examination of the lesion as it is frequently misdiagnosed with other types of skin pathology. In our case, the child presented with painless swelling of the left infraauricular region. The initial cytology and imaging were unable to provide a definite diagnosis. An excision biopsy was done, and a histopathological examination was suggestive of Pilomatricoma. Therefore, Pilomatricoma ought to be considered in the differential diagnosis of head and neck lesions in hopes of providing a better understanding on this pathological lesion.

The Girl With the Bleeding Earlobe Mass

ABSTRACT

Pilomatrixomas, also known as epithelioma calcificans, are benign tumors of hair follicle matrix cells that are often mistaken for other lesions, especially cutaneous abscesses. We report an illustrative case in which a teenage girl developed a red, swollen earlobe that required multiple care visits and interventions until definitive diagnosis and treatment were provided. Although the lesion was initially treated as an abscess, it continued to progress in size and discomfort. The correct diagnosis was established after imaging and complete excision with pathologic examination. Ultimately, our patient was subjected to avoidable procedures that carried the risk of potentially negative cosmetic sequelae before the proper intervention. Although abscesses are common, it is important for clinicians to avoid incision and drainage of lesions, unless the diagnosis is certain.

Bilateral Cervical Pilomatricoma: A Diagnostic Dilemma for the Pediatric Otolaryngologist

Pilomatricomas are benign skin tumors often encountered by otolaryngologists but frequently misdiagnosed. Although they can occur at any age, they commonly present in children as a discolored superficial lesion adhered to the overlying skin. Accurate preoperative diagnosis is crucial for appropriate management, which is surgical in most cases. Here, we present bilateral pilomatricomas mimicking features of several other diagnoses in a pediatric patient. The patient was successfully treated with surgical excision. This case presented a unique diagnostic challenge, as the lesions exhibited features of several common diagnoses. In general, surgical management of pilomatricoma is curative, and recurrence is rare.

Multiple pilomatrixomas: Case report and literature review

Pilomatrixoma is a rare, benign, circumscribed, calcifying epithelial neoplasm that is derived from hair matrix cells. Multiple pilomatrixomas are uncommon. We describe a case of multiple pilomatrixomas in a 23-year-old black woman who presented with lesions on her face and back. Based on the results of the clinical examination, she was provisionally diagnosed with either calcified sebaceous cysts or calcified lymph nodes. She underwent surgical excision of the masses. On histopathology, the lesions were identified as pilomatrixomas. We attribute our original failure to diagnose this condition to our lack of familiarity with it. We discuss the presentation, differential diagnosis, and other characteristics of pilomatrixomas.

Preauricular Pilomatricoma Manifesting as an Aggressive Mass

Pilomatricoma is an uncommon benign skin tumor arising from the hair follicle. It usually occurs in the head and neck region and is typically found in the pediatric age group particularly girls. The tumor has inconsistent clinical features and may manifest as a small superficial lesion with benign features or a large and seemingly aggressive lesion with local invasion. Due to its variable clinical presentations, it can occasionally be misdiagnosed as a malignant tumor. We encountered a case of pilomatricoma in a 12-year-old girl with a left preauricular swelling for two years, which became progressively larger and more painful in the few weeks before presentation. Clinically, the swelling resembled a malignant parotid tumor. Multiple fine-needle aspirations were performed, but the cytology results were all inconclusive. Subsequent computed tomography scan revealed a well-defined calcified subcutaneous mass with suspicious parotid involvement. The case was posted for tumor excision and superficial parotidectomy. Intraoperatively, however, the mass could be easily separated from the parotid gland. Histopathological examination of the excised specimen showed characteristic ghost cells, basophilic cells, and ossifications typical of pilomatricoma. In conclusion, preauricular pilomatricoma may pose a diagnostic dilemma. A heightened knowledge of the disease is needed for early recognition of its clinical and imaging features to prevent aggressive therapy than is required.

Paediatric neck ultrasonography: a pictorial essay

The neck structures are located very superficially and are therefore easy to explore by ultrasound examination. Ultrasonography is crucial for the detection of neck pathologies in children. High-frequency probes (10-15 MHz) are used for the ultrasound examination on the patient lying in supine decubitus and with their neck stretched out. The outcome of the exam depends mainly on the child's cooperation-hence the need for warm sonographic gel and a comfortable cushion to place under the patient's shoulders. The complete scan of the neck includes the evaluation of the thyroid and salivary glands and the vascular structures as well as the lymph node analysis. In children and adolescents, the thymus is often visualised in the supraclavicular and jugular scans. It appears as a structure, usually hypoechoic, with thin hyperechoic straps, though echogenicity increases with age. In this pictorial essay, the main pathological conditions of the neck in paediatric age will be examined, such as thyroid dysgenesis, thyroiditis, thyroid nodules, lymphadenopathies, cystic lesions, haemangiomas and vascular malformation, cervical thymus, fibromatosis colli and pilomatrixoma.

[Pilomatricoma: a study of 22 cases]

Pilomatricoma is a common and benign skin tumor of childhood arising from the hair follicle matrix. It is an often misunderstood adnexal tumor, confused with other skin lesions. The most common sites of pilomatricome are the head and the neck. The aim of this study was to report a series of 22 cases with unusual forms collected in the dermatology department from January 2006 to May 2015. The study included 16 women and 6 men. The average age was 23.3 years (4- 80 years). Cervicofacial location was observed in 12 cases, 2 patients had multiple locations, a 4 year-old boy had frontotemporal location, a 14 year-old girl had face and forearm location and a 48 year-old patient had subungual location. Clinical features were typical in all cases, with subcutaneous nodules with a stony-hard consistency. All patients underwent excision of nodules under local anesthesia. Histological study supported a completely excised Malherbe's mummified tumor without malignancy. No patients relapsed. The originality of our study lies in the presence of exceptional locations in laterovertebral region, on limbs and in the subungual region and of unusual age of onset (80 year-old) as well as the presence of multiple tumor locations reported in 2 children.

Review of pediatric head and neck pilomatrixoma

INTRODUCTION

Pilomatrixoma is a benign skin tumor, which is commonly found in the head and neck region. It usually presents as an isolated lesion and rarely undergoes malignant transformation. It is not uncommon for these tumors to be misdiagnosed.

OBJECTIVE

To review the clinical characteristics of head and neck pilomatrixomas in the pediatric population.

METHODS

A systematic review was completed by searching ten databases to identify studies reporting findings on pilomatrixoma in the pediatric population. Eligible articles were independently assessed for quality by two authors.

RESULTS

A total of 17 studies met the inclusion criteria totaling 318 pediatric patients. The age of diagnosis ranged from 3 months to 17 years of age. The female to male ratio was 1.65:1. In 14 articles, in which pilomatrixoma was located in the head and neck region, 76 (25%) lesions were found in the neck while 229 (75%) were present in the head region. Three articles exclusively described ophthalmologic pilomatrixoma. Even though pilomatrixoma presents with classical features, the clinical diagnostic accuracy when confronting this lesion averaged 43%. The definitive treatment was surgical excision with a very low recurrence rate.

CONCLUSION

Head and neck pilomatrixoma in the pediatric population has a typical presentation with a low clinical diagnostic accuracy. Awareness of this lesion and its clinical appearance can improve its diagnosis. We hereby suggest a management algorithm for suspected pilomatrixoma.

Uncommon benign tumour of the skin: infraorbital pilomatricoma

Pilomatricoma is a relatively rare tumour of the skin derived from primitive basal cells of epidermis that differentiate into hair matrix cells. It comprises approximately 1% of all benign skin tumours. The most common sites for pilomatricomas are the head, neck and upper extremities. A 44-year-old woman, admitted to our department, underwent an orthopantomography examination, which revealed a well-circumscribed 1.6×1.4 mm radiopaque mass superimposed between the medial wall of the right maxillary sinus and lateral wall of the nasal cavity. Clinically, it was firm and mobile, and remained attached to the underlying skin when palpated. A cone beam CT scan was performed to ascertain its location and anatomic relations. Subsequently, it was totally excised under local anaesthesia. Histopathological evaluation of the lesion reported it to be a pilomatricoma.

TGF-β1-dependent induction and nuclear translocation of FHL2 promotes keratin expression in pilomatricoma

Pilomatricoma is a tumour derived from hair matrix cells, which shows progressive keratin expression. Tumorigenesis is frequently associated with activating mutations in β-catenin gene inducing nuclear expression of β-catenin protein. The present study analysed the role of transforming growth factor-β1 (TGF-β1) and four-and-a-half LIM domain protein 2 (FHL2) in pilomatricoma in synopsis with their expression patterns in human anagen hair. Human anagen hair showed TGF-β1 and nuclear FHL2 expression in the outer root sheath layer separated from nuclear β-catenin staining, which was observed in cells of matrix and inner root sheath layers. Correspondingly, 41 out of 50 pilomatricomas showed co-labelling of TGF-β1 and nuclear FHL2 in tumour cells, which mostly lacked nuclear β-catenin expression. Tumoural proliferation (ki67) was associated with nuclear β-catenin staining but not with expression of nuclear FHL2. In early pilomatricomas, TGF-β1 expression was observed in few peripheral tumour cells showing absent or faint nuclear FHL2 co-staining. TGF-β1 expression extended in growing tumours going along with strong nuclear FHL2 co-labelling as well as progressive keratin 14 and keratin 1 expression. In vitro, cultured human keratinocytes showed weak to marked autocrine TGF-β1 expression; in case of enhanced TGF-β1 expression associated with keratin 10 staining. TGF-β1-treatment of cultured human keratinocytes induced nuclear and cytoplasmatic FHL2 staining as well as keratin 14 staining. Accordingly, siRNA-mediated FHL2 knockdown of TGF-β1-stimulated keratinocytes reduced keratin 14 staining. In conclusion, tumoural TGF-β1 secretion seems to induce nuclear translocation of co-factor FHL2 mediating progressive keratin expression in pilomatricoma.

Molecular pathology of skin neoplasms of the head and neck

CONTEXT

Skin neoplasms include the most common malignancies affecting humans. Many show an ultraviolet (UV)-induced pathogenesis and often affect the head and neck region.

OBJECTIVE

To review literature on cutaneous neoplasms that show a predilection for the head and neck region and that are associated with molecular alterations.

DATA SOURCES

Literature review.

CONCLUSIONS

Common nonmelanoma skin cancers, such as basal and squamous cell carcinomas, show a UV-induced pathogenesis. Basal cell carcinomas are characterized by molecular alterations of the Hedgehog pathway, affecting patched and smoothened genes. While squamous cell carcinomas show UV-induced mutations in several genes, driver mutations are only beginning to be identified. In addition, certain adnexal neoplasms also predominantly affect the head and neck region and show interesting, recently discovered molecular abnormalities, or are associated with hereditary conditions whose molecular genetic pathogenesis is well understood. Furthermore, recent advances have led to an increased understanding of the molecular pathogenesis of melanoma. Certain melanoma subtypes, such as lentigo maligna melanoma and desmoplastic melanoma, which are more often seen on the chronically sun-damaged skin of the head and neck, show differences in their molecular signature when compared to the other more common subtypes, such as superficial spreading melanoma, which are more prone to occur at sites with acute intermittent sun damage. In summary, molecular alterations in cutaneous neoplasms of the head and neck are often related to UV exposure. Their molecular footprint often reflects the histologic tumor type, and familiarity with these changes will be increasingly necessary for diagnostic and therapeutic considerations.

Recurrent giant pilomatrixoma of the face: a case report and review of the literature

Pilomatrixoma, also known as pilomatricoma, is a benign tumor that originates from the matrix of the hair root. It usually presents as a single, slow-growing subcutaneous or intradermal firm nodule with a general size of less than 3 centimeters (cm) in diameter. However, giant pilomatrixomas (more than 5 cm) have been reported infrequently. It is more common in females and usually presents during the first two decades of life (60%) as an asymptomatic, mobile, hard, elastic mass. Most of the cases are benign and affect the face. The authors report a rare case of a giant pilomatricoma of the cheek and discuss the surgical management of these lesions, histopathological findings, and review of the literature.

Facial dermatologic lesions in children

This article briefly reviews some of the most common skin lesions in the head and neck of a child. Benign "lumps and bumps" are very common in children and it is prudent for the pediatric maxillofacial surgeon to be familiar with their presentation, workup (including radiographic studies), and definitive surgical management. Inflammatory and infectious lesions require prompt treatment to avoid more serious sequelae of progressive infection and scarring.

Imaging and review of a large pre-auricular pilomatrixoma in a child

A 10-year-old girl presented with a mildly tender mass in the right preauricular region. The mass became larger, and the overlying skin turned purple. There was no clinical response to a course of either cephalexin or clarithromycin. The remainder of the head and neck examination was normal including normal facial nerve function. Lyme titers and a computed tomographic (CT) scan with contrast of the facial region were obtained. The CT scan demonstrated the lesion to be superficial to the parotid gland. The lyme titer was elevated and doxycycline was begun. The mass appeared to reduce in size after doxycycline treatment, but then grew and turned erythematous. The lesion was surgically excised and was vascular with calcification and cheesy inclusions. The mass was quite close to the skin and the clinical diagnosis at the time of surgery was a pilomatrixoma, which was corroborated on pathological evaluation.

Pilomatricoma as a diagnostic pitfall in clinical practice: report of two cases and review of literature

Pilomatricoma (PMC) is a relatively uncommon benign skin neoplasm arising from the skin adnexa. Since the first description of PMC in 1880, there has been a gradual increase in understanding of the morphologic features and clinical presentation of this tumor. However, difficulties still persist in making clinical and cytologic diagnosis. We report the clinical and histopathological findings of two cases of pilomatricoma. In case 1, a 10-year-old girl presented with a right upper back mass. In case 2, a nine-year-old girl presented with a left ear lobe mass. The clinical findings in both the cases were suggestive of epidermoid/dermoid cyst. However, subsequent histopathologic examination confirmed these cases as pilomatricoma. This report reveals that pilomatricoma is a frequently misdiagnosed entity in clinical practice. The purpose of this article is to create awareness among clinicians on the possibility of pilomatricoma as a cause of solitary skin nodules, especially those on the head, neck or upper extremities.

Pilomatrix carcinoma of the thoracic spine: case report and review of the literature

CONTEXT

Pilomatrixoma is a common head and neck neoplasm in children. Its malignant counterpart, pilomatrix carcinoma, is rare and found more often in men.

METHOD

Case report of a 21-year-old man with pilomatrixoma of the thoracic spine that underwent malignant degeneration to pilomatrix carcinoma.

FINDINGS

The appearance of a painless mobile axillary mass was followed by severe back pain 1 year later. Imaging revealed a compression fracture at the T5 level. The patient underwent resection of the axillary mass and spinal reconstruction of the fracture; the pathology was consistent with synchronous benign pilomatrixomas. Three months later he presented with a recurrence of the spinal lesion and underwent further surgical resection; the pathology was consistent with pilomatrix carcinoma. He received adjuvant radiotherapy and at his 1-year follow-up examination had no sign of recurrence.

CONCLUSION/CLINICAL RELEVANCE

Pilomatrix carcinoma involving the spine is a rare occurrence. It has a high incidence of local recurrence, and wide excision may be necessary to reduce this risk. Radiotherapy may be a helpful adjuvant therapy. Clinicians should be aware of this entity because of its potential for distant metastasis.

Pilomatricoma: Experience of the Hospital for Sick Children

Background

Pilomatricoma (calcifying epithelioma of Malherbe) is a common skin neoplasm in the pediatric population that is often misdiagnosed as other skin conditions or tumours.

Objectives

The objective of the present retrospective study was to review the clinical and histopathological presentation of this neoplasm in children.

Methods

The records of the pathology department at The Hospital for Sick Children, Toronto, Ontario, were searched for all cases of pilomatricoma between 2001 and 2006. The records of these patients were reviewed to determine sex, age, location and size of the tumour, pathological features and recurrence rate. All patients underwent surgical excision of the lesions.

Results

A total of 93 lesions in 85 patients were identified. The median age was 8.7 years. Of the 85 patients diagnosed with pilomatricoma, 44 (52%) were female. In all cases, the initial presentation was an asymptomatic, slow growing, superficial hard mass with bluish discolouration. The most common sites of occurrence were the face (48%), neck (21%) and upper limbs (18%). The size of the surgical specimens collected ranged from 0.1 cm to 2.6 cm. The diagnosis was confirmed by histopathological examination in all cases. Ghost cells and basaloid cells were described in most of the cases (83%). There were no recurrences in this series.

Conclusions

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 face, neck and upper limbs. The diagnosis can generally be made by clinical examination. The treatment of choice is surgical excision, and the recurrence rate is very low.

Pilomatricoma of the Maxillofacial Area in the Northern Regional Jordanian Population: Report of 31 Cases

PURPOSE

To analyze the clinicopathologic features of pilomatricoma affecting the maxillofacial area in Jordanians.

PATIENTS AND METHODS

Records of the Department of Pathology at Jordan University of Science and Technology were reviewed for patients with biopsied pilomatricoma of the maxillofacial region received during the 11-year period extending between 1991 and 2001. These were retrieved, reviewed, and analyzed for age, gender, location, clinical features, and treatment.

RESULTS

There were 31 cases with an age range from 4 to 48 years (mean, 16.7). The majority (74%) of patients were in their first (45%) and second (29%) decades of life with a male to female ratio of 1 to 1.4. The periorbital (36%), the periauricular (28%), and the upper cervical region (23%) were the affected areas. The majority of cases presented as a painless skin nodule with a duration varying from 2 months to 3 years. The majority (97%) of tumors were between 0.5 cm and 2 cm in diameter. Histologically, almost 50% of tumors showed shadow cells alone. All tumors were removed surgically.

CONCLUSIONS

The clinicopathologic characteristics of pilomatricoma of the maxillofacial area in Jordanians are similar generally to those in other countries. Maxillofacial surgeons need to be more aware of this lesion and should consider it in the differential diagnosis of dermal masses they encounter.

Simultaneous multiple pilomatrixomas

We report a 10-year-old girl with synchronous multiple pilomatrixomas. Pilomatrixomas are generally solitary tumors; synchronous multiple tumors are very rare. Multiple or recurring tumors may be found in association with various syndromes, and multiple tumors may be familial. Concurrent disorders were not identified in our patient and the etiology of her pilomatrixomas was not understood. Thorough examination of the patient and long-term follow-up are necessary with these tumors.

Pilomatricoma in childhood: a retrospective study from three European paediatric centres

Pilomatricoma is characterised as a common, slowly growing benign cutaneous tumour that appears generally within the first decades of life. The clinical diagnosis is frequently missed, especially by the paediatrician unfamiliar with these tumours. We present the experience gained in three European tertiary care paediatric centres with the treatment of pilomatricoma and also current data on the aetiology, clinical presentation and management. A retrospective study was carried out in 83 patients suspected for pilomatricoma during a 7-year period (1996-2002) at the departments of Paediatric Surgery of the Children's University Hospital "Federico II", Naples, Hospital "San Bortolo", Vicenza and "Aghia Sophia" Children's Hospital, Athens. The age range was from 10 months to 17 years, median age 8 years. All patients were treated by surgical excision and all specimens were examined by histopathological assessment. The follow-up varied from 5 months to 6 years. The correct diagnosis was made preoperatively in 68 patients (82%). The female/male ratio was 2:1. The sites of occurrence were the head (47.5%), especially in the periorbital region, the neck (9%), the upper limbs (35.5%), the inferior limbs (4%) and the thorax (4%). Each patient exhibited a single pilomatricoma except for two patients who had multiple lesions (2.4%). One of them had Steinert disease (myotonic dystrophy). No recurrences were observed during the follow-up period.

CONCLUSION

Pilomatricoma is one of the most common cutaneous adnexal neoplasms in children. Surgical excision including clear margins and its overlying skin in most cases is the treatment of choice. The recurrence as well as malignant evolution is rare.

[Pilomatrixoma as a problem in ophthalmic surgery]

Pilomatricoma, relatively rare benign tumour of the hair matrix cells, is usually misdiagnosed preoperatively. This result in unnecessary extensive surgery. In order to improve diagnosis and treatment of pilomatricoma, authors discuss their ten years experience (28 cases) with this tumour.

Pilomatrixoma:

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.