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Background: Pilomatricoma, a benign childhood skin tumor, presents diagnostic challenges due to its manifestation variations and requires surgical excision upon histological confirmation of its characteristic cellular features. Recent artificial intelligence (AI) advancements in pathology promise enhanced diagnostic accuracy and treatment approaches for this neoplasm., Methods: We employed a multiscale transfer learning model, initiating the training process at high resolutions and adapting to broader scales. For evaluation purposes, we applied metrics such as accuracy, precision, recall, the F1 score, and the area under the receiver operating characteristic curve (AUROC) to measure the performance of the model, with the statistical significance of the results assessed via two-sided P tests. Our novel approach also included a retrosynthetic saliency mapping technique to achieve enhanced lesion visualization in whole-slide images (WSIs), supporting pathologists' diagnostic processes., Results: Our model effectively navigated the challenges of global-scale classification, achieving a high validation accuracy of up to 0.973 despite some initial fluctuations. This method displayed excellent accuracy in terms of identifying basaloid and ghost cells, especially at lower scales, with slight variability in its ghost cell accuracy and more noticeable changes in the 'Other' category at higher scales. The consistent performance attained for basaloid cells was clear across all scales, whereas areas for improvement were identified in the 'Other' category. The model also excelled at generating detailed and interpretable saliency maps for lesion visualization purposes, thereby enhancing its value in digital pathology diagnostics., Conclusion: Our pilomatricoma study demonstrates the efficacy of a deep learning-based histopathological diagnosis model, as validated by its high performance across various scales, and it is enhanced by an innovative retrosynthetic approach for saliency mapping., Competing Interests: Declaration of competing interest The authors state that they have no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

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., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Pilomatricoma has various manifestations on color Doppler ultrasound, and a differential diagnosis is challenging. The objective of this study was to investigate which characteristics of skin lesions on color Doppler ultrasound are effective in distinguishing pilomatricoma from epidermoid cyst and dermatofibrosarcoma protuberans., Materials and Methods: Records of patients with pilomatricomas (n = 63), epidermoid cysts (n = 76), and dermatofibrosarcoma protuberans (n = 19) who underwent color Doppler ultrasound evaluation and surgical excision were reviewed. The anatomical distribution and color Doppler ultrasound characteristics of these lesions were analyzed. The 63 pilomatricomas were categorized into five types based on their color Doppler ultrasound characteristics, and the roles of these five types in the differential diagnosis of the aforementioned diseases were studied., Results: Pilomatricomas, epidermoid cysts, and dermatofibrosarcoma protuberans exhibited some similar characteristics. Dominantly markedly hyperechoic or hyperechoic appearance, posterior acoustic shadowing, and the presence of vascularity were the major characteristics of pilomatricomas. The pilomatricomas could be categorized into five types, with type II having a diagnostic performance of sensitivity of 65.08%, specificity of 98.95%, area under the receiver operating characteristic curve (AUC) of 0.743, positive predictive value of 97.62%, and negative predictive value of 81.03% for the diagnosis of the aforementioned skin diseases., Conclusion: A combination of dominantly markedly hyperechoic or hyperechoic appearance, posterior acoustic shadowing, and the presence of vascularity exhibits higher diagnostic performance for the differential diagnosis of pilomatricomas, epidermoid cysts, and dermatofibrosarcoma protuberans., (© 2024 The Authors. Skin Research and Technology published by John Wiley & Sons Ltd.)

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., (Copyright © 2023 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Pilomatricomas are tumors originating from the matrices of hair follicles. Giant pilomatricomas, defined as pilomatricomas that are 5 cm or larger, are benign but may appear malignant clinically. We present the case of a 69-year-old man with a rapidly growing mass on his scalp. When he visited our department, the tumor measured 10.0×6.0×4.0 cm and showed inflammation and ulceration. Magnetic resonance imaging and 18 F-fluorodeoxyglucose positron emission tomography-computed tomography showed findings resembling lymph node metastasis from a malignant tumor. However, upon an incisional biopsy, the tumor was diagnosed as a pilomatricoma. Therefore, we performed an excisional biopsy instead of radical surgery and lymph node dissection. The tumor was ultimately diagnosed as a giant pilomatricoma based on the excisional biopsy, and the patient received reconstruction only at the site of the defect. A giant pilomatricoma can be mistaken for a malignant tumor due to its characteristics. In such uncertain cases, it can be helpful to first perform an excisional biopsy., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 by Mutaz B. Habal, MD.)

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., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Pilomatrixoma is a benign, asymptomatic skin tumor that forms from hair follicle matrix cells. Most are under 3 cm in diameter and occur on the head, face, or neck. Bullous appearance is very rare in pilomatrixoma. In this case report, we present a case of bullous pilomatrixoma of unusual size, region, symptoms, and patient age. It had been misdiagnosed as a keloid and as dermatofibrosarcoma protuberans. Early treatments were ineffective. The patient approached our outpatient facility and underwent excision. He was then diagnosed with pilomatrixoma by pathological examination. The clinical appearance of this case was quite difficult to diagnose, even MRI and B-ultrasonic examinations provided limited diagnostic evidence. Given the revelations from this case, we reemphasize the importance of performing a biopsy (if patients refused operation or preferred conservative treatment) before any invasive treatment to minimize economic or time loss of patients who have difficulties in diagnosis., (© 2022 Wiley Periodicals LLC.)

Background: Cutaneous lesions present a diagnostic challenge to radiologists and clinicians alike. Pilomatricoma is the second most common skin neoplasm in childhood, yet there are limited reports in the literature focusing on imaging in pediatric patients., Objective: To characterize the typical and atypical US features of pilomatricoma in pediatric patients and to determine the performance of the adult-based Solivetti classification for assessing pilomatricomas in children., Materials and Methods: We retrospectively reviewed 169 US scans of pathologically proven pilomatricomas in 156 children performed over a period of 66 months. We evaluated images for the size of the lesion, borders, morphology, content, calcification, location on the skin and Doppler characteristics., Results: Most of the pilomatricomas presented as single dermohypodermic lesions with peripheral vascularity on color Doppler interrogation. The cheek was the most common location, followed by the arm. Solivetti type 2 US pattern was the most frequent, and peripheral hypoechoic halo was only observed in this type. One child had an anetodermic pilomatricoma, and 11 children had multiple lesions., Conclusion: We showed that pilomatricomas exhibit variable sonographic patterns. In our cohort, less than 50% of the lesions showed the characteristic hypoechoic rim and less than 30% of the cases presented as diffusely hyperechoic masses with posterior acoustic shadowing. Our results show that the Solvetti classification for the US assessment of pilomatricomas can be of value in children., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A classic pilomatricoma, which usually presents with an asymptomatic, solitary, firm, subcutaneous nodule in the head, neck, or extremities of the paediatric population, is easily diagnosed based on its characteristic clinical and histopathological features. However, its variants often pose particular diagnostic challenges to clinicians due to their rarity and diverse clinicopathological features. We present a new pseudocystic variant, manifesting as solid lesions floating in a fluid-filled sac., (© 2020 The Australasian College of Dermatologists.)

Pilomatrixoma is a benign subcutaneous tumour arising from the sebaceous glands. Mutation in the CTNNB1 gene is seen, suggesting beta-catenin misregulation may be the cause of pilomatrixoma. The preoperative diagnosis may be improved by the awareness of the fact that pilomatrixoma is a common and benign skin tumour of the head and neck region. It presents as a well-defined mass, which may be firm to hard in consistency, usually attached to the skin, but not to the underlying tissue. The colour of overlying skin appears a reddish-brown tinge, indicating that it could be a case of pilomatrixoma. Here, we report a case of pilomatrixoma of the cheek in a woman along with the CT findings and histopathological appearances. Dental surgeons should consider it as one of the differential diagnosis in superficial head and neck swelling with calcification., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

This study aimed to investigate the associations between the sonographic findings and duration of symptoms in children with pilomatricoma.This study included 86 children with 95 lesions confirmed to be pilomatricoma after pathological examination. The associations between symptom duration and sonographic observations, including the presence or absence of peritumoral hyperechogenicity, calcification, and vascularity were investigated. The internal echogenicity of each pilomatricoma was scored using a 5-point scale based on echogenic spots and calcification with posterior acoustic shadowing. The Mann-Whitney U and Kruskal-Wallis tests were used for statistical analysis.We found that the absence of peritumoral hyperechogenicity and severity of calcification were associated with increased symptom duration. Calcification, (present, 19.19 ± 18.99 months vs absent, 4.31 ± 3.24 months; P < .01) and peritumoral hyperechogenicity (present, 5.02 ± 5.80 months vs absent, 16.17 ± 18.24 months; P < .01), and grade of internal echogenicity (grade 0/1/2/3/4 = 3 months [1 patient]/4.33 ± 3.26 months [range, 1-12]/4.57 ± 3.46 months [range, 2-12]/10.89 ± 9.17 months [range, 3-28]/35.27 ± 19.16 months [range, 9-60], respectively; P = .01 and <.01) were associated with significant differences in symptom duration. There were no significant between-group differences in vascularity (6.01 ± 7.24 months; range, 1-48 vs 15.50 ± 19.12 months; range, 1-60; P = .08).Pilomatricomas with a relatively short symptom duration were more likely to exhibit peritumoral hyperechogenicity and calcification with less severe posterior acoustic shadowing compared to lesions with a longer symptom duration. These sonographic findings provided useful information that facilitated the correct and rapid diagnosis of pilomatricoma.

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., (© 2020 by the American Institute of Ultrasound in Medicine.)

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.

Cutaneous adnexal tumors include lesions with apocrine, eccrine, follicular, sebaceous, and mixed differentiation. Most are benign and sporadic, although malignant forms are occasionally observed and some cases develop in the setting of inherited syndromes. These tumors often cause immense diagnostic difficulty. Dermoscopy is a noninvasive technique that has greatly improved the diagnostic accuracy of different skin lesions, including these tumors. We provide a review of the literature on the dermoscopic structures and patterns associated with adnexal tumors. Most patterns associated with this kind of tumor are nonspecific and are observed in other nonadnexal tumors, especially in basal cell carcinomas., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Purpose: To describe the radiological characteristics of pilomatricomas on multi-detector computed tomography (MDCT) and magnetic resonance imaging (MRI), and to correlate the radiological findings and pathological features., Materials and Methods: The radiological findings of 41 pilomatricomas in 31 patients were retrospectively reviewed. The images were evaluated with emphasis on calcifications, reticular and ring-like appearances, enhancement patterns, circular target sign and peritumoral fat stranding, and correlating these with pathological features., Results: Of the 31 lesions evaluated by MDCT, 25(80.6%) showed different patterns of calcifications which included single in 12(38.7%) lesions and multiple in 13(41.9%) lesions, but peritumoral fat stranding was observed only in 2(6.5%) lesions. MRI scans were performed in 11 patients with 21 lesions, homogeneous and inhomogeneous hypointensities on T1-weighted (T1W) images were showed respectively in 14(66.7%) and 7(33.3%) lesions. On fat-suppressed (FS) T2-weighted (T2W) images, a ring-like hyperintensity was observed in all 21(100%) lesions, reticular hyperintensity, circular target sign, peritumoral fat stranding and secondary anetoderma were seen in 7(33.3%), 4(19%), 4(19%) and 1(4.8%) lesions, respectively; and a significant difference (P < 0.05) was found when comparing the maximum diameter of tumors with (2.3 ± 1.4 mm) and without (1.1 ± 0.3 mm) reticular hyperintensity. On contrast-enhanced T1W images, all 21(100%) lesions were found to have ring-like enhancement and 7(33.3%) of them showed reticular enhancement. The reticular and ring-like appearances on MR images respectively corresponded to the pathological edematous stroma and connective tissue capsule, and the four-layer structures of the circular target sign on FS T2W images also corresponded to pathological calcifications, shadow cells, epithelial cells and connective tissue capsule, respectively., Conclusions: The characteristic radiological findings associated with pilomatricomas include different patterns of calcifications on MDCT images and ring-like, reticular appearances and circular target sign on MR images. Radiological findings are well correlated with pathological nature., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Introduction: Pilomatrixoma, also known as calcifying epithelioma of Malherbe, is a superficial benign skin tumor that arises from hair follicle matrix cells. Although pilomatrixomas are well-recognized lesions, clinically they are frequently misdiagnosed as other skin conditions. By reviewing all the literature over the past 10 years, the aims of this article are to analyze the cause, clinical presentation, management, and outcome of pilomatrixoma among children and adults to gain a more complete understanding of this lesion in today's clinical context., Methods: A MEDLINE and EMBASE search was conducted from January 2005 to February 2015 using a combination of the terms: "child," "childhood," "adult," and keywords: "pilomatrixoma," "pilomatricoma," and "calcifying epithelioma of Malherbe." A total of 150 articles were reviewed., Results: The lesions occurred most commonly in the first and second decades (mean age 16 years and 7 months). The commonest presentation was of an asymptomatic, firm, slowly growing, mobile nodule. Only 16% were accurately diagnosed on clinical examination. Imaging in the form of ultrasound, computed tomography, and magnetic resonance imaging has been reported. Pathological diagnosis was achieved through incision, punch, and shave biopsies. Pathological findings are discussed and summarized in this review., Conclusion: Pilomatrixomas are thought to arise from mutation in the Wnt pathway and has been linked to several genetic conditions. It is commonly misdiagnosed preoperatively; however, with better awareness of the lesion, it can be appropriately treated while avoiding unnecessary diagnostic tests. Complete surgical excision with clear margins is almost always curative.

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., (© 2017 Wiley Periodicals, Inc.)

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., (© 2017 The Authors Journal of Clinical Ultrasound Published by Wiley Periodicals, Inc.)

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.

Background: Magnetic resonance imaging (MRI) findings of pilomatricomas have yet to be determined., Purpose: To assess the correlation between MRI and pathological findings of pilomatricomas., Material and Methods: MR images were obtained on patients with histologically proven pilomatricomas using a 1.5-T MR scanner. The images were retrospectively reviewed for size, signal intensity compared with skeletal muscles, and enhancement patterns. Furthermore, we assessed the presence of a reticular appearance, a ring-like appearance, and peritumoral fat stranding., Results: We included 11 consecutive patients with 12 histologically proven pilomatricomas (3 boys/men, 8 girls/women; age range, 4-76 years; mean age, 20 years; median age, 14 years). The tumors were located in the head and neck (n = 6), upper extremities (n = 5), and lower extremities (n = 1). The maximum tumor diameter was in the range of 7-32 mm (mean, 16.5 mm). On T2-weighted (T2W) images, five tumors showed homogeneous hypointensity, whereas six showed reticular hyperintensity and one showed cystic hyperintensity. On fat-suppressed T2W images, nine tumors showed reticular hyperintensity, eight showed ring-like hyperintensity, and five showed peritumoral fat stranding. On fat-suppressed gadolinium-enhanced T1-weighted (T1W) images, one tumor showed no enhancement, whereas three showed reticular enhancement and five showed ring-like enhancement. Histologically, edematous and fibrous stroma was observed in 10 tumors, tumor capsules in 11, and inflammatory cell infiltration of the peritumoral fat tissue in nine., Conclusion: MRI features of pilomatricomas included reticular and ring-like hyperintensities on fat-suppressed T2W images and reticular and ring-like enhancement on fat-suppressed gadolinium-enhanced T1W images., (© The Foundation Acta Radiologica 2015.)

Background: Ultrasonography (US) has recently proved to be useful in diagnostic dermatology. It is convenient to use, completely safe, and provides valuable information., Objective: This study was performed to compare the diagnostic accuracy of US with that of clinical diagnosis in patients with benign subcutaneous lesions., Methods: We retrospectively examined data for 100 patients with benign subcutaneous lesions who were diagnosed with US and either biopsy or surgery at Seoul National University Boramae Hospital between January 2010 and May 2013., Results: Ultrasonography significantly increased the diagnostic yield of benign subcuta-neous lesions (after physical examination [PE], 52.0%; after US, 82.0%; P < 0.005). Rates of sensitivity and specificity for the diagnosis of lipoma were 61.5 and 92.0%, respectively, after PE, and 100 and 100%, respectively, after US. Rates of sensitivity and specificity for the diagnosis of epidermal cysts were 69.4 and 78.4%, respectively, after PE, and 91.8 and 92.2%, respectively, after US. Additionally, rates of sensitivity and specificity for pilomatrixoma were 12.5 and 98.9%, respectively, after PE, and 75.0 and 100%, respectively, after US. Although the accuracy of diagnosis of vascular anomalies and nerve sheath tumors was increased after US, the difference was not significant (vascular anomalies: 40.0% after PE and 80.0% after US; nerve sheath tumors: 28.6% after PE and 42.9% after US)., Conclusions: This study suggests that US is a simple and reliable tool that can aid the diagnosis of benign subcutaneous lesions., (© 2015 The International Society of Dermatology.)

We report a case of 43-year-old man who presented with an enlarging, painless, palpable mass in the left breast for one year associated with surface blue discoloration of the skin. Mammogram showed a well-defined 2.3-cm mass with microcalcifications. Ultrasound revealed a well-defined, subcutaneous hypoechoic mass adherent to the skin with multiple bright foci. Ultrasound-guided needle biopsy produced a dark-colored sample corresponding to pilomatricoma on final pathology. Bilateral breast magnetic resonance imaging showed heterogeneously hyperintense in T1- and T2-weighted images with heterogeneous enhancement toward the delayed phase. Surgical resection was carried out with wide margins., (Copyright © 2015 Elsevier Inc. All rights reserved.)

A 40-year-old man presented to us with infertility. During scrotal ultrasonography, a heterogeneous nodular mass was seen in the right testicle. Surprisingly, histopathological examination revealed shadow cells, which are the characteristic feature of pilomatrixomas., (2014 BMJ Publishing Group Ltd.)

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.

We report a case of a woman who underwent a curative resection of an upper jaw tumor histologically verified as eosinophilic granuloma. To exclude possible multiorgan involvement, PET/CT imaging was performed and revealed a metabolically active, partially calcified lesion located on the chest wall surface and clinically corresponding to a gradually developing, round, subcutaneous infiltrate with erythematous overlying skin. After complete extirpation, the pathological finding was consistent with pilomatrixoma surprisingly, thus dismissing the suspected diagnosis of multi-system Langerhans cell histiocytosis.

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., (Copyright © 2012 Wiley Periodicals, Inc.)

A 3-year-old girl with a history of bilateral retinoblastoma presented with a new right lower periorbital mass that showed calcifications on ultrasound. She had previously undergone systemic and intra-arterial chemotherapy for retinoblastoma but had no evidence of active disease for at least 6 months previously. Her family and oncologists feared that this mass was an extraocular metastasis of her retinoblastoma. On excision, it was diagnosed as a pilomatrixoma, an uncommon benign neoplasm that originates from the matrix of the hair root. This is the first reported case of pilomatrixoma in a patient with retinoblastoma., (Copyright © 2013 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.)

A 56-year-old patient was referred for FDG PET/CT with a right preauricular lymph node fine-needle biopsy, suggesting poorly differentiated carcinoma and no obvious primary lesion. There was intense FDG uptake in the right preauricular nodule. The node was excised, and formal histology demonstrated a benign pilomatricoma rather than malignancy. Pilomatricoma is uncommon in adults and an unusual cause for marked FDG uptake, likely due to foreign body inflammation. Pilomatricoma can be either benign or malignant. The marked FDG uptake demonstrated in our patient with benign pilomatricoma also suggests that FDG PET cannot reliably grade this rare condition.

Diagnosis of pilomatrixomas may be difficult because they can mimic other clinical conditions. Color Doppler ultrasound had been proven useful in the study of localized lesions of the skin and can both define lesion morphology and determine blood flow changes in real time, and may thus help differentiate primary from secondary vascular skin lesions. We present 3 cases of pilomatrixomas that mimic vascular lesions of the skin on physical examination. Clinical, sonographic, intraoperative, and histologic images are provided to highlight the nature of these challenging cases., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Background: Calcifying epithelioma of Malherbe, or Pilomatricoma, is considered an uncommon cutaneous neoplasia, normally occurring in children as a solitary, firm, asymptomatic, hard, subcutaneous, slowly growing nodule on the face, neck, or proximal upper extremity. In literature, two Pilomatricoma ultrasound patterns are described: the totally calcified nodule and the hypoechoic nodule with internal calcific foci. High frequency ultrasound has not yet been applied for routine diagnosis of Pilomatricoma. The aim of the study was to retrospectively identify specific ultrasound features., Methods: We retrieved 124 histologically Pilomatricoma cases: 28 patients with 32 lesions were preoperatively evaluated with ultrasound., Results: 22/32 have shown a solid formation, hypoechoic, with a sharp outline. Of these 22, 10 lesions were completely calcifying and 12 partially calcified. In 3/32 lesions with uncertain diagnosis, ultrasounds showed a complex/mixed pattern with pseudo-fluid areas and microspots. 7/32 lesions with US different diagnosis included 3 complex lesions, 2 cystic lesions and 2 solid nodular lesions., Conclusion: In addition to well-known ultrasound patterns (completely calcified and partially calcified) we identified three new, not yet described, patterns that constitute the 31% of the cases: complex, pseudocystic and pseudotumoral.