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

Ultrasound features of benign paediatric lumps: radiology-pathology correlation

Ultrasonography is an appropriate first-line imaging technique for the characterisation of paediatric lumps, given its relative accessibility and absence of radiation exposure. Together with a thorough history and examination, ultrasonography can help to distinguish benign lesions from malignancy. It can also aid further characterisation of benign lesions to inform onward investigation and management. This review features the evaluation of common benign paediatric lumps together with their characteristic sonographic features, following correlation with histopathology results or clinical follow-up.

Granuloma annulare on ultrasound: a diagnosis to consider in pediatric skin lesions

BACKGROUND

Granuloma annulare (GA) is a rare, benign, inflammatory, self-limited, granulomatous dermatosis that affects children and young adults. The most frequent clinical form is localized GA. Deep GA generally presents as painless palpable subcutaneous nodules in the lower extremities, buttocks, hands and scalp. They may have a fast-growing firm subcutaneous mass presentation, mimicking a malignant lesion which requires an imaging evaluation. Diagnosis of deep GA can be more difficult and imaging evaluation is frequently performed, ultrasound being one of the techniques used.

OBJECTIVE

To describe the US characteristics of GA in a pediatric series.

MATERIALS AND METHOD

Descriptive, retrospective, 14-year study of all pediatrics GA cases.

RESULTS

Twelve pediatric cases with GA. 66% females. The lesions were mainly distributed in the extremities: 50% in the lower extremities and 42% in the upper extremities, mostly with multiple lesions. A total of 45 lesions were analyzed, 8 superficial lesions and 37 deep lesions. On ultrasound, the superficial GA corresponded to hypoechoic poorly defined solid plaque like or nodular lesions, located in the dermal-epidermal plane. The deep GA presented as solid nodular, poorly defined hypoechoic lesions that compromised the deep subcutaneous-aponeurotic plane.

CONCLUSION

GA is an inflammatory lesion that presents as a superficial or deep palpable nodule that predominantly affects children. Superficial and deep GA present characteristic findings on US that can guide the diagnosis. The radiologist needs to know its US appearance to be able to suggest the diagnosis, especially in multiples lesions.

Subcutaneous Granuloma Annulare vs. Subcutaneous Vascular Malformations in Children: A Diagnostic Challenge

OBJECTIVES

There are various subcutaneous lesions in children and often there is difficulty in obtaining an accurate diagnosis by non-invasive diagnostic procedures. Subcutaneous granuloma annulare (SGA) is a rare granulomatous disease that, even after imaging, is often mistaken for a low-flow subcutaneous vascular malformation (SVM). This study aimed to accurately identify clinical and imaging clues to distinguish SGA from low-flow SVM.

METHODS

We retrospectively analyzed complete hospital records of all children with a confirmed diagnosis of SGA and low-flow SVM who underwent MR imaging at our institution from January 2001 to December 2020. Their disease history, clinical and imaging findings, management, and outcome were evaluated.

RESULTS

Among 57 patients with granuloma annulare, we identified 12 patients (nine girls) with a confirmed SGA diagnosis who underwent a preoperative MRI. Their median age was 3.25 years (range 2-5 years). Of 455 patients diagnosed with vascular malformations, 90 had malformations limited to the subcutaneous area. Among them only 47 patients with low-flow SVM were included in the study and further analyzed. Our SGA cohort had a female predilection (75%) and a short history of lump appearance of 1.5 months. SGA lesions were immobile and firm. Before MRI, patients underwent initial evaluation by ultrasound (100%) and X-ray (50%). Surgical tissue sampling was performed in all SGA patients to establish a diagnosis. All 47 patients with low-flow SVM were diagnosed correctly by MRI. A total of 45 patients (96%) underwent surgical resection of the SVM. A careful retrospective review of imaging findings of patients with SGA and SVM showed that SGA present as homogenous lesions in the shape of an epifascial cap with a typical broad fascial base extending towards the subdermal tissue in the middle of the lesion. In contrast, SVMs always present with variable-sized multicystic or tubular areas.

CONCLUSIONS

Our study shows clear clinical and imaging differences between low-flow SVMs and SGA. SGA presents characteristically in the shape of a homogenous "epifascial cap," which distinguishes these lesions from multicystic heterogenous SVMs.

The epifascial cap: A typical imaging sign for subcutaneous granuloma annulare in children

Objectives

Subcutaneous granuloma annulare (SGA) is a rare, self-limiting granulomatous disease in children, commonly diagnosed by histopathology following biopsy or surgical excision. This study aimed to identify imaging clues for SGA that could expedite accurate diagnosis and avoid the need for biopsy in children.

Methods

We retrospectively analyzed complete hospital records of all children diagnosed with SGA at our institution from January 2001 to December 2020. Detailed disease history, imaging findings, management, and outcome were evaluated.

Results

We identified 28 patients (20 girls) at a median age of 3.75 (range 1-12.5 years). Ten patients presented with multiple lesions. Most lesions were located on the lower extremities (n = 26/41). Ultrasound examinations were performed on all patients, and 12 (43%) patients also received an MRI. Surgical intervention was conducted in 18 (64%) patients either by incisional biopsy (n = 6) or total excision of the lump (n = 12). In all patients who did not undergo surgery, SGA resolved spontaneously. A careful review of the MRIs led to the discovery of a characteristic imaging shape of SGA lesions: the epifascial cap with a typical broad circular base laying on the fascia, extending towards the subdermal/dermal tissue. This distinctive shape was evident in every patient in our cohort.

Conclusions

The "Epifascial Cap Sign" is a specific imaging sign for SGA, which to the best of our knowledge, helps distinguish this disease from other subcutaneous lesions. Recognition of this novel diagnostic sign combined with the historical and physical findings should enable clinicians to establish SGA diagnosis easily and diminish the need for further invasive diagnostic procedures.

Common Ultrasound Applications for Pediatric Musculoskeletal Conditions

PURPOSE OF REVIEW

To discuss the use of ultrasound for diagnosis and management of common pediatric musculoskeletal conditions through a case-based approach.

RECENT FINDINGS

Ultrasound is an essential diagnostic modality in the early detection of developmental dysplasia of the hips and can be used as early as 6 weeks of age when the ossific nucleus has not developed yet. Ultrasound is helpful in diagnosing traumatic injuries such as fractures and intramuscular hematomas, can visualize fracture healing at early stages, and can also be used to guide aspiration of hematomas that can help with decreasing pain and faster recovery. Ultrasound is superior to radiographs in evaluating joint effusions and soft tissue infections or masses and is better tolerated by children compared to other imaging modalities such as magnetic resonance imaging (MRI). Ultrasound is an easily accessible, affordable, non-invasive, and radiation-free imaging modality that is well tolerated by children and their families. It can aid in the diagnosis and management of a wide variety of musculoskeletal conditions including developmental, traumatic, and infectious etiologies, as well as in the evaluation of superficial soft tissue masses.

Ultrasound versus magnetic resonance imaging of soft-tissue lesions: competitive or complementary?

Soft-tissue lumps and bumps are a common referral for imaging in children and adolescents. The etiology of these lesions includes benign non-tumorous lesions, as well as benign and malignant tumors. Some of these lesions have a characteristic imaging appearance but others do not and require tissue sampling to make a diagnosis. MRI typically provides the best overall characterization of soft-tissue masses; however, in some cases US provides complementary information to that provided by MRI that can help make a diagnosis.

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.

Imaging of Pediatric Soft Tissue Tumors and Tumor-like Conditions

Lumps and bumps are frequently seen in children, and the vast majority are a result of trauma, infection, or inflammation. True soft tissue neoplastic lesions are rare; however, their wide and complex classifications make these lesions challenging to manage. Imaging features are usually nonspecific, and a reasonable list of differential diagnoses can be generated following consideration of the clinical presentation, age, and anatomical location of the lesion. In this article, we offer a practical approach to diagnosing such lesions by discussing the most common three benign and malignant lesions in different anatomical regions stratified by age with emphasis on certain features that might aid in the diagnosis such as depth, multiplicity, calcification, or other specific imaging feature.

Ultrasonography of Pediatric Superficial Soft Tissue Tumors and Tumor-Like Lesions

Ultrasonography (US) is usually the first imaging examination performed to evaluate palpable or visible superficial soft tissue lesions that are common in children. Although clinical assessments, such as age at presentation, clinical course, and overlying skin discoloration, are important for the differentiation of pediatric soft tissue lesions, US allows a specific diagnosis of some typical benign lesions and helps in guiding further investigation since it provides detailed information about the lesion location, characterization including solid versus cystic, vascularity, and compressibility. Therefore, sufficient knowledge of the normal anatomy, proper ultrasonographic techniques, and the imaging findings of common and uncommon soft tissue lesions in children are crucial for accurate assessment and management of patients. In this article, we review the techniques and imaging findings focusing on the ultrasonographic features of a variety of superficial soft tissue lesions detected in children.

Chronic Thigh Pain in a Young Adult Diagnosed as Synovial Sarcoma: A Case Report

Synovial sarcoma is a slow-growing, intermediate- to high-grade neoplasm with extensive metastatic potential. Accurate diagnosis of synovial sarcoma may pose a challenge to providers because of its indolent growth and variable presentation. The findings of a soft-tissue, periarticular mass with calcifications in a young patient are highly suggestive of synovial sarcoma. Although different imaging modalities can aid in the diagnosis of synovial sarcoma, diagnostic certainty is typically only confirmed by biopsy and histologic analysis. We present a case describing the diagnostic workup of synovial sarcoma with an emphasis on imaging findings in a patient with increasing symptomatology spanning more than a decade.

LEVEL OF EVIDENCE

V.

Clinical and sonographic features of pediatric soft-tissue vascular anomalies part 1: classification, sonographic approach and vascular tumors

Sonography can be used in the management of pediatric soft-tissue vascular anomalies for diagnosing, for assessing lesion extent and for evaluating complications and response to therapy. The sonographic technique includes a combination of gray-scale imaging with color and spectral Doppler techniques. However the interpretation of the sonographic findings requires correlation with the clinical findings, some of which can be easily obtained at the time of scanning. This has to be combined with the use of appropriate nomenclature and the most updated classification in order to categorize these children into the appropriate management pathway. In this article, which is part 1 of a two-part series, the authors review the current classification of vascular anomalies, provide a clinical and a sonographic approach to these lesions, and review the most relevant clinical and sonographic features of vascular tumors including infantile and congenital hemangiomas, tufted angioma, kaposiform hemangioendothelioma, pyogenic granuloma, intramuscular capillary-type hemangioma and angiosarcoma.

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.

Assessment of the Pediatric Foot Mass

Masses in the pediatric foot are relatively uncommon and can present a diagnostic challenge. The literature lacks a comprehensive overview of these types of lesions. Most are benign soft-tissue lesions that can be diagnosed on the basis of history and physical examination. However, some rare malignant neoplasms can mimic benign masses. It is imperative to recognize these lesions because the consequences of a delayed or missed diagnosis can be substantial. A thorough history and physical examination of all pediatric patients with foot lesions are crucial to ensure that any lesion not readily identified as benign is appropriately managed.

Point-of-Care Ultrasound to Diagnose Infantile Parotid Hemangioma

Soft tissue masses are common in the pediatric population and may represent a broad range of conditions. Point-of-care ultrasound can be used for rapid visualization and assessment of soft tissue masses in the emergency setting. We report a case of a pediatric head and neck mass in which point-of-care ultrasound was used to identify an infantile parotid hemangioma.

Imaging findings of Hoffa's fat pad herniation

BACKGROUND

We report the radiologic findings of herniation of Hoffa's fat pad through a defect in the lateral patellar retinaculum in young children who presented with painless masses visible by ultrasound (US) only with flexion of the knee.

MATERIAL AND METHODS

Six children, between the ages of 1-8 years, presented with an anterolateral knee mass that was not tender and was only seen and palpable with knee flexion. An US was performed in all patients, magnetic resonance imaging (MRI) in 2 patients and knee radiographs in 1 patient.

RESULTS

US imaging displayed focal herniation of Hoffa's fat pad within the infrapatellar region through a defect of the lateral retinaculum, visible only during dynamic imaging when the knee was in flexion. MRI performed in knee extension did not demonstrate a mass; however, it revealed a focal defect in the lateral retinaculum in the region of the abnormality. Radiographs were normal.

CONCLUSION

Focal herniation of Hoffa's fat pad is an uncommon cause of an anterolateral knee mass in young children. When a knee mass is only identified in flexion, focal fat herniation through a defect in the retinaculum should be suspected and a dynamic US should be performed.

Ultrasound of the joints and entheses in healthy children

BACKGROUND

Tendon insertion pathologies such as enthesitis and apophysitis in children can result from trauma, overuse syndrome and arthritis. Knowledge of the US appearance of normal joints by age might aid diagnosis of pathologies.

OBJECTIVE

We describe the age-related sonographic features of the elbows, knees and feet in healthy children, providing a reference for the normal appearance of tendon insertions, apophyseal cartilage and bursae.

MATERIALS AND METHODS

This is a prospective cross-sectional study of 30 healthy children. Children were grouped according to age: group 1 (4-9 years, n = 11), group 2 (10-13 years, n = 9) and group 3 (14-18 years, n = 10). Children completed pain and function questionnaires and underwent a standardized joint examination by a pediatric rheumatologist. The common extensor, common flexor, quadriceps, patellar and Achilles tendons and plantar fascia insertions were evaluated with gray-scale and power Doppler ultrasound. The anterior elbow, suprapatellar and retrocalcaneal bursae were evaluated for fluid. We measured the apophyseal cartilage thickness at the enthesis. Correlation analyses examined associations between age and tendon thickness. We used ANOVA, with location as a repeated measure, to test for gender differences in cartilage thickness.

RESULTS

Children had a median age of 12.4 years and 55% were boys. All 360 entheses appeared normal on gray-scale imaging. There was a strong linear relationship between tendon thickness and age. Tendon vascularity was only present in young children (group 1), in 7/22 (32%) quadriceps tendons. Peri-tendinous power Doppler signal was seen at seven sites: two patellar, four quadriceps and one common flexor tendon, and all these children were in group 2. Suprapatellar bursal fluid <3 mm was detected in 9/60 (15%) knees. Of the children in group 1, boys had thicker apophyseal cartilage than girls at the medial epicondyle, patellar poles and os calcis (P < 0.05).

CONCLUSION

Tendon vascularity may be a normal finding in young children, and mild peri-tendinous vascularity is not uncommon in children 10-13 years of age. Tendon thickness has a linear relationship with age; however cartilage thickness varies across sites and also differs as a function of gender.