Pilomatricomas in children: imaging characteristics with pathologic correlation

Atypical and giant proliferating pilomatrixoma of the eyelid: a clinicopathological report

BACKGROUND

Pilomatrixoma is an uncommon benign skin neoplasm originating from the hair follicle. Here, we report a rare case of giant and atypical proliferating pilomatrixoma affecting the eyelid.

CASE PRESENTATION

A 47-year-old male presented with a solitary, giant mass on his left upper eyelid, which had recently shown progressive enlargement. The lesion appeared well-circumscribed with a firm consistency, and measuring 7 × 10 cm. Orbital computed tomography scan revealed no intraorbital extension. The lesion was surgically excised. Histopathological examination identified the mass as an atypical proliferating pilomatrixoma, characterized by a minimal infiltrating margin of the deep plane and focal cytological atypia of the basaloid cells. No recurrence was observed up to one year postoperatively.

CONCLUSIONS

Pilomatrixoma is a rare periocular tumor with potential for malignant transformation, often mimicking other lesions in this region. Therefore, any enlarging masses in this area should be excised for histopathological evaluation to rule out malignancy.

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.

Key Points to Select a Device for Dermatologic Ultrasound

What points to consider when selecting a device for practicing dermatologic ultrasound is an excellent question. After we met the requisites published in the guidelines for practicing dermatologic ultrasound, it is necessary to consider the main objective of the use because it is not the same to be focused mostly on the avoidance of the puncture of important facial vessels such as the case of injectors of cosmetic fillers in comparison to the use of operators that need to deal with the diagnosis and monitoring of a wide range of dermatologic pathologies. Currently, a broad variety of ultrasound devices meets the minimum requirements for practicing these examinations in the market. Thus, small, portable, and high-end devices may present advantages and limitations that must be balanced according to the primary purposes and the budget. Moreover, the shape and footprint of the probes can make difficult or facilitate a dermatologic procedure. Other points to consider are the type of storage and the need for technical service. In summary, there are key points that we need to consider when we select a dermatologic ultrasound device in dermatology or aesthetics.

Periocular pilomatrixoma in childhood: Clinical feature and differential diagnosis

PURPOSE

To explore the clinical characteristics, imaging features, and differential diagnosis of periocular pilomatrixoma in children and provide evidence for clinical diagnosis and treatment.

METHODS

Retrospective analysis of the clinical characteristics, preliminary diagnosis, imaging features, treatment, and follow-up of the cases of pediatric periocular pilomatrixoma treated at our hospital.

RESULTS

A total of 59 patients from 4 months to 13 years of age (median age 4 years) were collected; 18 cases (30.51%) were misdiagnosed as other diseases in preliminary diagnoses. Seven cases underwent computed tomography (CT) examination, with CT value ranging from 63.4 Hounsfield Units (HU) to 952.0 HU (median value 151.0 HU). Six cases underwent magnetic resonance imaging (MRI) examination; two patients underwent an enhanced scan. The results showed that the rim of the lesion was enhanced, but the contents were not enhanced. All patients underwent surgical treatment. No recurrence was found from 1 month to 5 years of follow-up.

CONCLUSIONS

Periocular pilomatrixoma is a relatively common tumor in children, which can easily be misdiagnosed clinically as other diseases, such as sebaceous and dermoid cysts. Although not generally recommended, CT can be of significant value in the diagnosis of pilomatrixoma. MRI is of little value in the diagnosis of this disease. If CT images show high or density, the possibility of pilomatrixoma should be considered.

Imaging palpable tumors in pediatrics: Part 2

Palpable tumors in children are a common reason for consulting a radiologist. The origin of these lesions varies widely, and although they are common, classic radiology books do not cover some of them. This series of two articles aims to review the clinical and radiological characteristics of a selection of palpable tumors in children that radiologists need to be familiar with.

Skin sonography in children: a review

Skin lesions are not uncommon in children, and most of them are benign. However, they can be a matter of concern. Although in most cases the diagnosis can be suspected based on clinical history and physical examination, in some cases clinical findings are nonspecific. High-frequency color Doppler US is a noninvasive technique that can play a relevant role in these cases and give important anatomical information for final clinical management. US can be helpful to avoid unnecessary surgery, plan a surgical excision and avoid advanced imaging studies such as MRI and CT, which have a lower resolution for the skin. Different lesions can look similar on US, and clinical correlation is always important. The purpose of this article is to show a variety of skin lesions that occur in children, emphasizing clinical-sonographic correlation, and to familiarize pediatric radiologists with the US technique and sonographic appearance of common skin lesions in children.

Pediatric chest wall masses: spectrum of benign findings on ultrasound

A palpable finding along the chest wall is a frequent indication for pediatric US. Accurate identification of benign lesions can reassure families and appropriately triage children who need follow-up, cross-sectional imaging, or biopsy. In this pictorial essay, we review chest wall anatomy, illustrate US techniques and discuss key US imaging features of common benign lesions and normal variants.

Ultrasound findings in 156 children with 169 pilomatricomas

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.

Ultra-High-Frequency Ultrasound in the Evaluation of Paediatric Pilomatricoma Based on the Histopathologic Classification

Background: Pilomatricoma (PM) is one of the most common benign tumours in children. However, the inaccuracy of preoperative diagnosis and evaluation is high. Non-invasive examinations, including dermoscopy and ultrasound are helpful for diagnosing and evaluating PM. To date, ultra-high-frequency ultrasonographic features of PM have been rarely studied. Objective: We aimed to investigate the ultra-high frequency ultrasonographic features of PM in a large paediatric cohort and to determine the associations of these features with the clinical features of different histological subtypes of PM. Methods: This was a retrospective study. Patients who had both preoperative ultra-high-frequency ultrasonographic evaluation and pathological diagnosis of PM were enrolled. A series of infantile haemangiomas and cutaneous cysts during the same period were included as controls. Histological findings, including the stage, calcifying type, and ultrasonographic features of each lesion, were described. Results: A total of 133 patients with PM were included, and 147 PM lesions were analysed. The male-to-female ratio was 1:1.58, and the median age of onset was 91 (range: 10-188) months. On ultra-high-frequency ultrasonography, PM presented as heterogeneous (144/147, 98.0%), well-demarcated (143/147, 97.3%), and hypoechoic (126/147, 85.7%) tumours located between the deep dermis and subcutaneous tissue (139/147, 94.6%). The most common features were internal echogenic foci (135/147, 91.8%), hypoechoic rim (133/147, 90.5%), and posterior acoustic shadowing (94/147, 63.9%). Fourteen (9.5%) lesions were histologically categorized in the early stage, 58 (39.5%) in the fully developed stage, 65 (44.2%) in the early regressive stage and 10 (6.8%) in the late regressive stage. Three calcifying types, including scattered dots, clumps and arcs, were observed on histologic examination, which corresponded well with grey-scale imaging on ultra-high-frequency ultrasonography. Each calcifying type was significantly different in various histological stages (P = 0.001), among which scattered dots were mainly present in the early and fully developed stage and arc-shaped calcifying were present in the regressive stages. Calcification was observed in skin cysts, while there was more frequent posterior enhancement, less frequent posterior shadowing, and hypoechoic rim than PM. Haemangioma also presented as a hypoechoic tumour on grey-scale imaging. However, haemangioma was homogeneous and rarely calcifying. Conclusions: PM is a heterogeneous, well-demarcated, hypoechoic tumour located between the deep dermis and the subcutis on ultra-high-frequency ultrasonography. The most common features are internal echogenic foci (calcifying) and hypoechoic rim. Calcifying types can help in the staging of PM. Ultra-high-frequency ultrasound is a useful tool for the diagnosis and evaluation of PM.

Sonographic characteristics of pilomatricomas and their association with symptom duration

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.

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.

An Unusual Tumor of the Ear: Pilomatricoma in a Middle-Aged Woman

Pilomatricoma is a benign tumor arising from hair follicle matrix cells, presenting as an asymptomatic, firm, slow growing, mobile, superficial skin nodule typically in children. This lesion with an atypical clinical presentation is frequently misdiagnosed as other skin lesions and even as malignant entities regardless of detailed cytological, imaging examinations; the site of occurrence is one of the keys to accurate diagnosis. Here, we present a case of pilomatrixoma involving the ear, the cymba conchae of the auricle, which is an extremely rare site for the lesion in a 52-year-old woman. The present case suggests that this benign tumor needs to be included in the differential diagnosis in patients who present with an atypical auricular lesion.

Trichilemmal Cyst: Clinical and Sonographic Features

OBJECTIVES

In this study, we retrospectively reviewed the clinical and sonographic features of patients with trichilemmal cysts.

METHODS

Sonographic findings of 54 cases of trichilemmal cysts were retrospectively analyzed from 50 patients, including 4 cases of proliferating trichilemmal cysts. Associated factors of internal calcification-positive cases were also evaluated.

RESULTS

The mean age of the 50 patients was 43.4 years (range, 15-80 years) and the female-to-male ratio was 1.3. Overall, 68% of the trichilemmal cysts in the 54 lesions were located in the scalp, and 15% were located in the extremities. All 54 lesions were preoperatively examined by sonography and showed well-defined, oval-shaped structures located in subcutaneous soft tissues close to the dermis. Of the 54 lesions, 72% were hypoechoic masses, 89% were heterogeneous, and 65% had internal calcification. Among the internal calcification-positive cases, the mean age of the patients was 43.4 years, and the female-to-male ratio was 0.6. Of these lesions, 83% were located in the scalp. We did not find any significant association between calcification, age, or sex (P = .993 and P = .99); however, lesions present in the scalp were significantly associated with internal calcification (P = .005). 81% of the 54 lesions displayed posterior enhancement. but the color Doppler sonography of all lesions revealed no vascularization.

CONCLUSIONS

Trichilemmal cysts should be considered to diagnose of well-defined, hypoechoic lesions with internal calcification and posterior sound enhancement in the subcutaneous soft tissues of the scalp or extremities upon sonography.

Sonography of pediatric superficial lumps and bumps: illustrative examples from head to toe

Superficial lumps and bumps are extremely common in children, and the vast majority ultimately prove to be benign. Duplex/color Doppler ultrasound (US) has emerged as the first-line imaging modality for the evaluation of these superficial pediatric masses because it provides a means for rapid acquisition of information including size, shape, location, internal content and vascularity. More important, it does so without utilizing radiation, iodinated contrast material or sedation/anesthesia. In this review, we present the sonographic findings of a variety of cases ranging from head to toe that are either uncommonly seen or were diagnosed in an atypical fashion (i.e. ultrasound). In situations where the lesion is too deep, hyperechoic or large to be fully assessed within the field of view or if malignancy is suspected, then additional cross-sectional imaging is warranted for further evaluation.

MR imaging findings of pilomatricomas: a radiological-pathological correlation

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.

MR Imaging of Soft-Tissue Tumors of the Upper Extremity

Certain soft-tissue tumors seem to be specific to the upper extremity; most are benign. Knowledge of key magnetic resonance features, with clinical history and epidemiologic knowledge, can assist the radiologist in establishing optimal diagnosis. Indeterminate lesions require biopsy to exclude malignancy.

Let's face it - 13 unusual causes of facial masses in children

Facial swelling is commonly encountered in paediatric patients and is typically related to an underlying infection. The spectrum of possible causes, however, is wide, and includes traumatic, inflammatory, nutritional and neoplastic aetiologies. In this pictorial essay we present 13 examples of rare conditions selected from a total of 136 MRI examinations performed at our institution between April 2007 and May 2013. These include HIV-associated malignancies such as a case of plasmablastic lymphoma, parotid gland tumours including a parotid hamartoma, rare congenital lesions such as a thyroid fetiform teratoma, and infective lesions including tuberculosis of the mandible. In many cases, only minimal information could be gleaned from the literature, particularly with regard to imaging findings. An analysis of the spectrum of masses and specific clinical presentations allowed for the construction of a diagnostic flowchart which may serve to assist in unusual cases.

TEACHING POINTS

• Facial swelling is commonly encountered in paediatrics, with a wide spectrum of possible aetiologies. • MRI is the favoured imaging modality for accurate assessment. • Facial swelling is typically infectious in nature, but includes various benign and malignant causes. • This pictorial essay presents 13 examples of rare conditions with corresponding imaging.

Imaging submandibular pathology in the paediatric patient

A wide range of pathologies may arise from the submandibular space (SMS) or submandibular gland (SMG) in children. We review herein the normal anatomy of the SMS and describe the role of imaging in the evaluation of SMS lesions. A schematic approach for the categorisation of SMS pathology based on imaging characteristics is provided.

Characterizing pilomatricomas in children: a single institution experience

BACKGROUND/PURPOSE

Pilomatricomas, or calcifying epitheliomas of Malherbe, are among the most common superficial cutaneous soft tissue lesions in children. Familiarity with the presenting signs and symptoms allows for the diagnosis to be made on physical examination alone in most patients, avoiding expensive and unnecessary diagnostic imaging.

METHODS

A retrospective IRB-approved review of surgical pathology archives and medical records of all patients undergoing excision of pilomatricomas between 1982 and 2010 was performed to determine the characteristics of the pilomatricoma tumors. Data regarding gender, age, location, size of tumor, and histopathology were collected.

RESULTS

There were 916 pilomatricomas resected in 802 patients. Fifty-five percent of the patients were girls (441 patients). The median age at the time of resection was 6 years (range 5 months to 18 years). Multiple lesions were found in 43 patients (5%). The most common location was head and neck (n = 529, 58%), followed by upper limbs (n = 214, 23%), trunk (n = 130, 14%), and lower limbs (n = 43, 5%). Information on size was available for 674 lesions; mean lesion diameter was 14.0 ± 7.4 mm. Twenty-eight patients (3%) had either recurrent (n = 11) or metachronous (n = 17) lesions resected at our institution, with a median interval of 12 months after initial resection (range 5 weeks to 5 years). No cases of pilomatrix carcinoma were observed.

CONCLUSION

The majority of pilomatricomas occur in the head and neck, although they can present in any location. Approximately 5% of children have multiple lesions. Pilomatricomas occur slightly more commonly in girls, and 66% of lesions occur in children < 10 years of age. Complete surgical excision is necessary to prevent recurrence. Recurrences and pilomatrix carcinoma are very rare if complete excision is achieved.

Ultrasound evaluation of superficial lumps and bumps of the extremities in children: a 5-year retrospective review

Ultrasonography is commonly requested for evaluation of palpable soft-tissue masses of the extremities in children. Although malignancy is quite rare in these children, it remains a primary diagnostic concern. As a result, knowledge of the common and uncommon soft-tissue lesions as well as sonographic techniques for optimized evaluation are crucial for accurate assessment. This review describe the sonographic imaging appearance of the most commonly encountered superficial soft-tissue lesions at a tertiary academic pediatric hospital. Features of malignancy and findings warranting further evaluation such as lesion size, heterogeneity, vascularity and depth of involvement are also discussed.

A 5-year-old girl with an enlarging mass at the elbow

Pilomatrixoma is a rare benign neoplasm that presents as a solitary, hard, mobile, subcutaneous mass. Pilomatrixomas can be found on any hair-bearing region of the body, with the upper extremity being the second most common location. Pilomatrixomas are common in children, and have a higher frequency in girls. We present a case of left-arm pilomatrixoma in a 5-year-old girl. Surgical excision was curative. Pediatric orthopedic surgeons should be familiar with this benign tumor when evaluating a calcified soft-tissue mass in the extremities of a child.

Magnetic resonance imaging of a cystic pilomatricoma in an ankle joint

Pilomatricoma, also known as calcifying epithelioma of Malherbe, is an asymptomatic, slow-growing, benign dermal neoplasm that originates from hair cortex cells. The most common sites are the head and neck (68.2%), followed by the trunk (14.4%) and the upper (15.3%) and lower (2%) extremities. The majority (60%-70%) of tumors develop in the first 2 decades of life. A typical pilomatricoma presents as a firm, calcified, dermal nodule appearing as a solid mass in subcutaneous tissue on computed tomography or magnetic resonance imaging.This article describes the case of a 42-year-old man who presented with nontender soft tissue swelling in the right ankle joint. Radiographs and magnetic resonance imaging findings showed an inflamed cystic mass with calcification in the lateral malleolar area of the right ankle joint. These atypical magnetic resonance imaging features around the ankle joint led to confusion with other disease entities, including chronic bursitis, pigmented villonodular synovitis, rheumatoid nodules, and gout. After complete excision of the mass, histological examination revealed a cystic pilomatricoma.Although rare, a cystic pilomatricoma should be considered in the differential diagnosis of soft tissue masses with calcification.

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.

Pilomatrixomas presenting as vascular tumors on color Doppler ultrasound

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.

Diagnosis of pilomatricoma using an otoscope

Pilomatricoma is a benign tumor that presents as a 3-30-mm, firm, solitary, deep, dermal or subcutaneous tumor on the head, neck, or upper extremities. The clinical diagnosis is often made by the firm, sometimes rock-hard texture of the skin. The diagnosis can be confirmed by a skin biopsy or excision of the lesion. We have recently noted that pilomatricomas appear as a black mass in the skin when the lesion is transilluminated by placing the light of a fiberoptic otoscope adjacent to the skin lesion. To our knowledge, this is the first report demonstrating preoperative diagnosis of pilomatricoma by transilluminating the lesion with an otoscope.

Epithelioma of Malherbe: new ultrasound patterns

Backround

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, pseudocistyc and pseudotumoral.

Pilomatricomas: the diagnostic value of ultrasound

OBJECTIVE

The purpose of this study was to analyze statistically significant diagnostic factors for pilomatricoma on the basis of ultrasonographic features.

METHODS

Sonographic images were retrospectively reviewed from 44 pilomatricomas, and from 43 control subjects with other subcutaneous tumors. Two radiologists determined the tumoral shape, margin, echotexture, echogenicity, posterior shadowing, posterior enhancement, hypoechoic rim, internal calcification, and vascularity.

RESULTS

The reliable diagnostic factors for pilomatricoma were hypoechogenicity (P < 0.001), heterogenicity (P < 0.05), internal calcification (P < 0.001), hypoechoic rim (P < 0.001), and posterior shadowing (P < 0.001). Scattered dots were the most common patterns of internal calcification. A combination of hypoechogenicity, heterogenicity, internal calcification of scattered-dot pattern, and a hypoechoic rim was a statistically significant difference between the two groups (P < 0.001; odds ratio, 21).

CONCLUSIONS

The features of heterogeneous echotexture, internal echogenic foci in scattered-dot pattern, and a hypoechoic rim or posterior shadowing itself could be discriminative ultrasonographic criteria for differentiating pilomatricomas from other subcutaneous tumors.

Pediatric soft-tissue tumors and pseudotumors: MR imaging features with pathologic correlation: part 2. Tumors of fibroblastic/myofibroblastic, so-called fibrohistiocytic, muscular, lymphomatous, neurogenic, hair matrix, and uncertain origin

In the final part of this two-part review article on soft-tissue masses in children, the magnetic resonance (MR) imaging features, clinical findings, and pathologic findings in a wide variety of tumors, including those of fibroblastic/myofibroblastic origin, so-called fibrohistiocytic tumors, smooth-muscle tumors, skeletal-muscle tumors, tumors of uncertain differentiation, and lymphoma, are described. Other neoplasms that are not included in the World Health Organization classification of soft-tissue tumors but may be seen clinically as soft-tissue masses, specifically dermatofibrosarcoma protuberans, neurogenic tumors and pilomatricoma, are also included. In contrast to the tumors reviewed in Part 1 of this review, the MR imaging features and clinical findings of the tumors included here are largely nonspecific. However, MR imaging is useful in determining site of tumor origin, extent of disease, and relation of tumor to adjacent anatomic structures, and for follow-up after therapy. In some of these entities, the combination of findings may aid in narrowing the differential diagnosis, such as persistent low signal intensity on T1- and T2-weighted images in some fibroblastic lesions, identification of hemosiderin and a synovial origin in pigmented villonodular synovitis, or the presence of multiple target signs on T2-weighted images in deep plexiform neurofibroma. In a large number of cases, however, tissue biopsy is required for final diagnosis.

MR imaging manifestations of skin tumors

In this study, we evaluated MR imaging findings of skin tumors and categorized them into four types: (1) discrete mass lesions of the dermis and epidermis, (2) mass lesions of the subcutis with or without abutment to the skin, (3) diffuse or localized skin thickening without a true mass, and (4) a skin mass with bone destruction. The categorization of MR images may be useful in the differential diagnosis of skin tumors.

Pilomatricoma: Sonographic features

Pilomatricomas (also known as calcifying epitheliomas of Malherbe) are benign subcutaneous tumors that arise from the cutaneous adnexa and usually affect young subjects. They typically present as solitary asymptomatic nodules located in most cases on the face or neck. On ultrasonography, pilomatricomas appear as hypoechoic lesions with inhomogeneous echo structures, well-defined margins, and posterior shadowing. Color Doppler generally reveals a single artery that penetrates the lesion and gives rise to multiple intralesional branches. Diagnosis is based on clinical and histological findings. The authors present a typical case of pilomatricoma diagnosed on the basis of clinical and sonographic findings that were subsequently confirmed by histology.