Pilomatrixoma and its Imitators

Introduction: Pilomatrixomas are benign neoplasms derived from hair follicle matrix cells. They are among the most common soft tissue head and neck tumors of childhood. Pilomatrixomas are typically isolated, slow-growing, firm, nontender masses that are adherent to the epidermis but mobile in the subcutaneous plane. This clinical presentation is so characteristic that many experienced surgeons will excise suspected pilomatrixomas without prior imaging. We reviewed the results of this approach to determine whether physical examination alone differentiates pilomatrixomas from other similar soft tissue lesions of the pediatric head and neck. Methods: Computerized review of all pilomatrixomas over a 20-year period in a single academic pediatric otolaryngology practice. Results: 18 patients presented to our pediatric otolaryngology practice between 2001 and 2021 with historical and physical findings consistent with pilomatrixoma. Of the 18 patients, 7 were male and 11 were female. Ages ranged from 1.5 to 14 years, with a mean of 7.5 years. Most of the lesions (12) were located in the head and face, while the rest (6) were found in the neck. All patients were treated with complete surgical excision. Pathology confirmed pilomatrixoma in 15 patients. The remaining 3 children were found to have an epidermal inclusion cyst, a ruptured trichilemmal cyst, and a giant molluscum contagiosum lesion, respectively. One additional patient presented with a small lesion of the auricular helix that was thought to be a dermoid cyst, but proved to be a pilomatrixoma on histologic examination. Discussion: As pilomatrixomas are common and have a very characteristic presentation, surgical excision without prior diagnostic imaging will lead to correct treatment in the majority of cases. High resolution ultrasonography can help to confirm the diagnosis preoperatively, but is not definitive in large case series. Most of the cystic lesions that imitate pilomatrixoma will ultimately require surgical excision.

Invention of automated numerical algorithm adopting binarization for the evaluation of scalp hair coverage: An image analysis providing a substitute for phototrichogram and global photography assessment for hair diseases

BACKGROUND

The efficacy of therapeutic modalities for hair disease can be evaluated globally by photo assessment and more precisely by phototrichogram (PTG). However, the latter procedure is laborious, time consuming, subject to inter-observer variation, and requires hair clipping.

OBJECTIVE

To establish an automated and patient/investigator friendly methodology enabling quantitative hair amount evaluation for daily clinical practice.

METHODS

A novel automated numerical algorithm (aNA) adopting digital image binarization (i.e., black and white color conversion) was invented to evaluate hair coverage and measure PTG parameters in scalp images. Step-by-step improvement of aNA was attempted through comparative analyses of the data obtained respectively by the novel approach and conventional PTG/global photography assessment (GPA).

RESULTS

For measuring scalp hair coverage, the initial version of aNA generally agreed with the cumulative hair diameter as assessed using PTG, showing a coefficient of 0.60. However, these outcomes were influenced by the angle of hair near the parting line. By integrating an angle compensation formula, the standard deviation of aNA data decreased from 5.7% to 1.2%. Consequently, the coefficient of determination for hair coverage calculated using the modified aNA and cumulative hair diameter assessed by PTG increased to 0.90. Furthermore, the change in hair coverage as determined by the modified aNA protocol correlated well with changes in the GPA score of images obtained using clinical trials.

CONCLUSION

The novel aNA method provides a valuable tool for enabling simple and accurate evaluation of hair growth and volume for clinical trials and for treatment of hair disease.

A comparative study of pilomatricoma and epidermoid cyst with ultrasound

AIM

To explore and compare the ultrasonic (US) features of pilomatricoma (PM) and epidermoid cyst (EC) in the differential diagnosis and improve the accuracy of US diagnosis of PM.

MATERIALS AND METHODS

Three hundred and nine patients who underwent US examination before surgery with a histopathological diagnosis of PM or EC after surgery were analysed retrospectively. The patients were categorised into the training and validation sets according to the inspection times. Univariate analysis was undertaken on the US and clinical features of PM and statistically significant variables (p<0.05) were included in the multivariate logistic regression model to establish a diagnostic model.

RESULTS

The results demonstrated that the multivariate logistic regression model for PM was statistically significant (p<0.001). The risk factors included posterior echo attenuation and hypoechoic halos (odds ratio [OR] = 9.277, 10.254) and the protective factors included age, diameter thickness, and posterior echo enhancement (OR=0.936, 0.302, 0.156). The performance of the diagnostic model was tested using the training set (area under the receiver operating characteristic curve [AUC] = 0.974, 95% confidence interval [CI] = 0.955-0.994) and the validation set (AUC = 0.967, 95% CI = 0.926-1.000), which demonstrated good discriminant ability.

CONCLUSIONS

The diagnostic accuracy for PM was higher than that for EC when the nodule is characterised by posterior echo attenuation, hypoechoic halos, smaller thickness, and younger age. The US diagnostic model developed may be used to guide the diagnosis of PM.

Cranial pilomatricoma: a diagnosis to consider

Pilomatricomas are benign tumors of the hair follicle that occur frequently in the scalp region. They occur most often in children. We describe a case of pilomatricoma in a teenager, referred to neurosurgery for excision. This diagnosis should be considered in the workup of scalp lesions, and this case report should serve to draw attention to this entity.

Two Cases of Malignant Proliferating Trichilemmal Tumor (MPTT) and Review of Literature

Malignant proliferating trichilemmal tumors (MPTTs, malignant proliferating pilar tumors) are theorized to originate from the outer root sheath of the hair follicle which resembles the isthmic portion of the hair follicle and epithelium of the lower hair follicle in catagen phase.1 They may develop de novo or arise from a pre- existing trichilemmal cyst or proliferating trichilemmal tumor. The tumors typically present with rapid growth on the scalps of women over the age of 50. In this review, we present two cases of MPTT, presenting on the scalp of a 69-year-old woman and the scalp of a 53-year-old woman. Both tumors were successfully treated with surgery and radiation. In addition to the classic histologic features, pilomatrical differentiation was also seen in case 1, a histologic feature that has rarely been described. In this paper, we review previously reported cases and summarize basic demographics, lesion size, location, treatment method, and patient outcome.

Distinguishing a Trichilemmal Cyst From a Pilomatricoma With Ultrasound

OBJECTIVES

To determine whether ultrasound (US) could distinguish a trichilemmal cyst from a pilomatricoma preoperatively.

METHODS

Ultrasound images of 61 pathologically proven trichilemmal cysts and 90 pathologically proven pilomatricomas were analyzed retrospectively. Two radiologists evaluated several US features. The sensitivity, specificity, Youden index, and predictive values of statistically significant US features were assessed. Parallel combined tests, serial combined tests, or both were performed to identify US features with high statistical significance.

RESULTS

Results from individual US features were not satisfactory; however, serial combined tests that included absence of complete internal echogenic foci, absence of a hypoechoic rim, absence of peritumoral hyperechogenicity, and absence of vascularity showed higher diagnostic utility. The sensitivity, specificity, Youden index, positive predictive value, and negative predictive value for correctly identifying a trichilemmal cyst were 74%, 88%, 0.62, 80%, and 83%, respectively. If 1 of these 4 US features was not a match for a trichilemmal cyst, pilomatricoma was considered.

CONCLUSIONS

It may be possible to distinguish trichilemmal cysts from pilomatricomas preoperatively using US. A combined test is superior to using any individual US feature.

Matrical carcinoma with melanocytic hyperplasia mimicking nodular melanoma in an elderly Mexican male

Matrical carcinoma with melanocytic hyperplasia (MCMH), previously referred to as malignant melanocytic matricoma, is a rare variant of the uncommon pilomatrical carcinoma, occurring most often on the head/neck and upper backs of middle-aged men. Nodular lesions may resemble pigmented basal cell carcinoma or melanoma clinically. We present a case of MCMH in a Hispanic patient with history of melanoma. Histopathological clues to appropriate diagnosis include basaloid cells, numerous atypical mitotic figures, matrical differentiation, shadow cells, strong diffuse nuclear and cytoplasmic expression of ß-catenin, and interspersed pigmented dendritic melanocytes.

A new case of the pilomatrixoma rare in the preauricular region and review of series of cases

Pilomatrixoma is considered a rare benign tumor arising from the hair follicle, most common in the head and neck region, but it is rarely diagnosed on a clinical basis. This report describes a new case of giant pilomatrixoma in a 36-year-old female patient. The nodule was localized in the preauricular area on the right side, appearing as a slow-growing, fixed, painless, with a hardened consistency, unusual giant (4.5 cm). A cone-beam computed tomography (CBCT) examination showed a slightly hyperdense lesion, and fine-needle aspiration cytology (FNAC) revealed peripheral blood and mononucleated inflammatory cells. After enucleation of lesion, a diagnosis of pilomatrixoma was confirmed. The differential diagnosis of pilomatrixoma is broad, because its characteristics also can be found in other lesions common to the head and neck. Thus, a lesion in the head and neck, adherent to the skin, and well demarcated, mainly in the young and in females, should be suspected as pilomatrixoma.

Pilomatricoma: An unusual cause of lump in a male breast

We present the case of a 48-year-old man who presented with a painless, progressively increasing lump in the left breast. The mammographic and sonographic appearance of the lesion was suspicious for malignancy. Fine needle aspiration cytology and histopathologic examination confirmed the diagnosis of pilomatricoma. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 46:209-211, 2018.

Calcifying epithelioma of malherbe (Pilomatrixoma): Clinical and sonographic features

PURPOSE

The purpose of this study was to describe the clinical and sonographic features of calcifying epitheliomas (pilomatrixomas).

METHODS

We retrospectively reviewed the clinical data and sonographic appearances of 59 cases of calcifying epitheliomas in 58 patients that were confirmed pathologically.

RESULTS

The mean age of the patients was 26 years (range, 5-69 years) and the female-to-male ratio was 1.2. All masses were located in subcutaneous soft tissues. Overall, 76.3% of the cases were located in the head and neck; the mean tumor size was 13 mm, and 72.9% of the cases were between 10 and 20 mm in size. Of the lesions, 62.7% were hypoechoic masses with internal calcifications, and 74.6% of them showed low or moderate internal vascularity on Doppler imaging.

CONCLUSIONS

The diagnosis of calcifying epithelioma should be considered in a patient with a painless, circumscribed, oval-shaped hypoechoic mass with internal calcifications and internal vascularity in the subcutaneous soft tissues of the head or neck. The mass may be small and have well-defined margins, with hypoechogenicity. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 46:3-7, 2018.

Anetodermic pilomatricoma: clinical, histopathologic, and sonographic findings

Pilomatricoma is a benign cutaneous tumor originatingfrom hair matrix cells. Anetodermic changes inthe skin overlying pilomatricomas are sometimesreported, although their precise mechanisms remainunknown. We present an unusual case of anetodermicpilomatricoma on the upper extremity of a 17-yearoldboy and report its clinical, histopathologic, andsonographic findings.

Generalized woolly hair with diventricular arrythmogenic cardiomyopathy: a rare variant of Naxos disease

Woolly hair may occur as an isolated problem of cosmetic concern or can be a part of a systemic disease (woolly hair syndrome) with underlying fatal cardiomyopathy. Two characteristic associations of woolly hair syndrome are Naxos disease and Carvajal syndrome. Naxos disease is characterized by woolly hair, palmoplantar keratoderma, and arrythmogenic right ventricular cardiomyopathy.In this report we describe a case of a young girl who presented with heart failure and was subsequently diagnosed as a case of generalized woolly hair with biventricular arrythmogenic cardiomyopathy.Our case represented a rare variant of Naxos disease in the advanced stage of arrythmogenic right ventricular cardiomyopathy; biventricular failure may occur with involvement of the interventricular septum and left ventricle causing congestive heart failure.

[Sonographic appearance of benign subcutaneous nodules--including color Doppler sonography]

OBJECTIVE

Color Doppler sonography is used to distinguish malignant from benign subcutaneous nodules because many malignant tumors show an increased number of vessels. But benign lesions, such as inflammatory epidermal cysts, pilomatricomas, palmoplantar fibromatoses show vascular flow signals. We analyze diagnostic factors for subcutaneous nodules on the basis of ultrasonographic appearance including color Doppler sonography.

METHODS

We evaluated with sonography 79 subcutaneous nodules in histopathologically proven cases.

RESULTS AND DISCUSSION

The diagnostic findings for 28 epidermal cysts were increased posterior echo(sensitivity 77%, specificity 90%). Vascular flow signals were seen in 7 cases(25%). The signals were seen from periphery to adjacent zone of the mass. They were accompanied by inflammatory granulation tissues histologically. The percentage of blood flow may be related to the percentage of "ruptured" epidermal cysts. Pilomatricomas (n = 9) had internal echogenic foci or Doppler flow signals, and no posterior enhancement (sensitivity 89%, specificity 78%). Seven pilomatricomas showed Doppler flow signals in the mass. The percentage of flow signals is explained by the degree of internal echogenic foci because remarkable calcium deposits producing posterior acoustic shadowing prevent us from flow signals. Palmoplantar fibromatoses (n = 5) were ill-defined margins and showed internal vascularity with no posterior enhancement (sensitivity 80%, specificity 94%).

CONCLUSION

More benign lesions showed vascular flow signals than reported previously. We have to diagnose subcutaneous nodules referring to not only color Doppler but also gray scale sonography.

Cystic pilomatrixoma of the wrist mimicking a ganglion cyst in a child

We describe a patient with a cystic pilomatrixoma mimicking a ganglion cyst on ultrasound. A 9-year-old boy had a subcutaneous mass on his left wrist. Ultrasound displayed a well-defined, multilobulated anechoic mass containing a few internal septa between the extensor pollicis longus and the extensor carpi radialis longus tendons. Sonographic findings suggested that the mass was a ganglion cyst. After excisional biopsy, histopathologic examination confirmed the diagnosis of pilomatrixoma.

The use of cone beam computed tomography for the assessment of trichorhinophalangeal syndrome, type I - a case report

Trichorhinophalangeal syndrome type I is a rare autosomal dominant disorder characterized by cone-shaped epiphysis, sparse fine hair, pear-shaped nose and variable growth retardation. The typical craniofacial features include thin upper lip, elongated philtrum, large outstanding ears, shortened posterior facial height associated with short mandibular ramus and reduced and superiorly deflected posterior cranial base. This report describes a 17-year-old male patient with trichorhinophalangeal syndrome type I and a detailed description of the craniofacial radiographic findings, including the use of cone beam computed tomography images for determination of the airway and temporomandibular joint discrepancies.

Clinical, biochemical, and genetic analysis of two korean patients with trichorhinophalangeal syndrome type I and growth hormone deficiency

Tricho-rhino-phalangeal syndrome type I (TRPSI) is a rare autosomal dominant hereditary disorder characterized by sparse hair, bulbous nose, long philtrum, thin upper lip, and skeletal abnormalities including cone-shaped epiphyses, shortening of the phalanges, and short stature. TRPSI is caused by mutations in the TRPS1 gene. Herein, we report two Korean cases of TRPSI. Although both patients (a 17-year-old-female and a 14-year-old male) had typical clinical findings, Patient 1 had an additional growth hormone (GH) deficiency. Treatment with recombinant human growth hormone (rhGH) 0.7 IU/kg/week led to an increase in growth velocity. Over 10 years of GH therapy, the mean growth velocity was 5.7 ± 0.9 cm/year. However, the patient 2 did not show apparent GH deficiency by GH stimulation test, had a poor response with rhGH therapy and GH therapy was discontinued after 6 months. Upon genetic analysis of the TRPS1 gene, two mutations were found. Patient 1 had a heterozygous mutation c.2520dupT (p.Arg841LysfsX3) which had not been previously reported. Patient 2 had a known nonsense mutation c.1630C>T (p.Arg544X). In summary, we were the first to report Korean patients with mutation of TRPS1.

[Diagnostic image. A woman with an abnormal screening mammogram]

A 56-year-old woman had an abnormal mammogram and a palpable mass in the left breast. Cytological and histological examination revealed a pilomatrixoma of the breast.

Proliferating pilomatricoma: a subset of pilomatricoma

Proliferating pilomatricoma is a histopathological entity that was proposed by Kaddu et al. in 1997. Proliferating pilomatricoma represents a distinctive histopathological entity; it should be differentiated from other benign and malignant neoplasms with features of hair matrix differentiation. Kaddu reported that an incompletely excised proliferating pilomatricoma may have a greater potential for local recurrence, because histopathologically it showed variable nuclear atypia and several mitotic figures. We report two patients with proliferating pilomatricoma and describe their clinical and pathological features.

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.

[Breast pilomatrixoma manifested as microcalcifications on mammography: report of two cases]

Pilomatricoma is a benign tumor of hair follicule origin corresponding to a firm subcutaneous nodule requiring histology for diagnosis. Only few breast pilomatricomas have been reported, with imaging showing well defined nodules with microcalcifications. We report two cases of intra-mammary pilomatricomas presenting as ACR BI-RADS 4 and 5 microcalcifications, suspicious for malignant tumors. Percutaneous biopsy confirmed the histological diagnosis. Malignant pilomatricomas have been reported, suggesting that all pilomatricomas should be resected.

Le pilomatricome isolé du bras : une localisation rare. À propos d'un cas

Pilomatrixoma also known as calcified epithelioma of Malherbe, is a rare benign cutaneous tumor. It is most commonly seen in the head and neck areas, during the first two decades of life. We report a 30-year-old female patient with a rare localisation of pilomatrixoma in the right arm. The pilomatrixoma was excised and at one year follow-up there has been no evidence of recurrence.

The common ultrasonographic features of pilomatricoma

OBJECTIVES

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.

[Pilomatrixoma of the head and neck in six cases]

Pilomatrixomas are benign neoplasms of the hair follicle, presenting as a mass in the head and neck region. Those arising from the parotid region may pose a diagnostic challenge. We present six patients (age range 6 to 68 years) with pilomatrixoma in the head and neck region. The lesions were located in the preauricular region in two cases, and in the periorbital region, the forehead, the neck, and in the dorsum of the nose in the other patients, respectively. The main complaint was a hard, slow-growing mass in all the cases. All the patients were treated surgically. Histopathologic diagnosis was pilomatrixoma. No recurrences or surgery-associated complications were observed in the follow-up period.

Pilomatricoma in the head and neck: CT findings in three patients

We report three cases of pilomatricoma, one in the infrahyoid neck and the others in the preauricular area. In all cases, CT showed well marginated soft tissue masses that were located mainly in the subcutaneous fat, partly attaching to the overlying skin. There was no evidence of infiltration to deeper structures. Substantial amounts of calcification were found in one tumor. Pilomatricoma should be included in diagnostic consideration when CT shows a well marginated subcutaneous soft tissue mass adherent to the skin with or without visible calcification in the head and neck region.

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.

Giant calcifying epithelioma of Malherbe (pilomatrixoma): imaging features

We present a case of giant calcifying epithelioma of Malherbe (pilomatrixoma) in the right upper arm of a 62-year-old man. It measured 18 x 12 x 8 cm in size, making it the largest of all the cases reported previously. CT clearly demonstrated a well-defined, subcutaneous mass with amorphous calcifications. The mass showed intermediate signal intensity on T2*-weighted MR images and slight contrast uptake on contrast-enhanced MR images. Histopathologically, this tumor showed no aggressive or malignant nature. The patient is without evidence of recurrence or metastasis 3 years following the resection.

Magnetic resonance imaging of pilomatricoma

Two patients (a 16-month-old boy and a 53-year-old man) were referred for MR imaging of a small, subcutaneous nodule at the forearm. Plain films were available in one patient and showed a non-specific well-circumscribed lesion. Upon ultrasonography (1 patient), a nodular, well-circumscribed, hyperechoic lesion was seen. In both cases spin-echo (SE) T1-weighted images (T1WI) showed homogeneous, intermediate signal intensity (SI). On gadolinium-enhanced T1WI (1 patient), no enhancement was observed. Both lesions showed predominant low-to-intermediate SI on T2WI. At histological examination characteristic findings of pilomatricoma were observed.