Soft Tissue Masses in Children
Section snippets
Clinical evaluation and imaging approach
Attempting to make the diagnosis of a soft tissue mass in a child in the absence of any clinical information is often futile because there is extensive overlapping of the imaging appearances of many of these conditions. Clinical information often adds significant clues that may narrow the differential diagnosis. Crucial clinical information includes age of the child, presence of pre-existing conditions that may be associated with specific tumors, location of the mass, duration of the presence
Pseudotumors
This section discusses lesions that are neither neoplastic nor vascular in origin.
Vascular lesions
This category, vascular lesions, represents the most common cause of soft tissue masses in children, encompassing 2 distinct types of lesions: hemangiomas (vascular tumors) and vascular malformations. Although the biology, clinical evolution, and management of each of these lesions can be different, the term, hemangioma, is often indiscriminately used to designate almost any type of vascular lesions, including vascular malformations, creating confusion not only to patients and their families
Adipocytic tumors
In contrast to adults, adipocytic tumors are rare in children, representing only 6% of all soft tissue neoplasms in the first 2 decades of life.24 In addition, in the pediatric age, there are other tumors that may contain fat that are not adipocytic in origin and should be considered in the differential diagnosis according to the clinical context. These include fibroblastic/myofibroblastic tumors, such as fibrous hamartoma of infancy and lipofibromatosis (discussed later), and vascular tumors,
Fibroblastic/myofibroblastic tumors
The category, fibroblastic/myofibroblastic tumors, frequent in children, includes a large variety of tumors, most of which have in common the presence of both fibroblastic and myofibroblastic cells. The most common or significant seen in the pediatric age are discussed, with exception of some tumors that are also seen in adults, such as deep fibromatosis, which are discussed in the article “Magnetic Resonance Imaging of Benign Soft Tissue Neoplasms in the Adult” by Walker and colleagues
Rhabdomyosarcoma
Rhabdomyosarcoma is the most common soft tissue sarcoma in the pediatric age, representing approximately two-thirds of all sarcomas in children and 7% to 8% of all pediatric malignant solid tumors.40 Although rhabdomyosarcoma is thought to arise from mesenchymal cells committed to skeletal muscle differentiation, it can occur in many different organs, even in those that lack striated muscle.40 In children, 2 major categories are recognized: embryonal and alveolar. The embryonal is the most
Angiomatoid Fibrous Histiocytoma
Angiomatoid fibrous histiocytoma used to be considered a subtype of malignant fibrous histiocytoma. In view of its distinct morphology and clinical features (earlier age of presentation, more superficial location, and lower metastatic potential and better prognosis), however, it is now considered a different entity.42 The precise cellular line of differentiation of this tumor remains unknown. At histology there are 4 key diagnostic features that tend to show some correlation with the imaging
Pilomatricoma
Pilomatricoma, also known by the old term, calcifying epithelioma of Malherbe, or by the etymologically incorrect, pilomatrixoma, is a benign subcutaneous tumor that arises from the hair cortex cells. Although this entity is not known by many radiologists, it represents the third most commonly resected superficial tumor in children after dermoid/epidermoid cysts and lymph nodes.48, 49
Pilomatricomas can occur practically at any age but are more common in children and adolescents. They can appear
Summary
Imaging plays a significant role in the evaluation of soft tissue masses in children. US is in most instances the primary imaging modality and is particularly useful in the diagnosis of vascular lesions, the most common cause of a pediatric soft tissue mass. US also aids in the diagnosis of fibromatosis colli, some pseudotumors, periarticular cysts, and pilomatricoma. MR imaging is also useful, especially in larger and deeper lesions. The interpretation of imaging findings, however, requires
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Abdominal Masses in Children
2023, Problem Solving in Pediatric ImagingAn atypical cervical median mass in an infant: A lipoblastoma
2020, Otolaryngology Case ReportsCitation Excerpt :In the absence of vascular anomalies within the tumor, it did not seem unlikely to correspond to a vascular lesion. Hence, even if the diagnosis was formally established by histopathology, imaging led to a presumptive diagnosis of lipoblastoma, in its encapsulated variant, which is much more frequent than the infiltrative variant [6,7]. Many patients with cervical lipoblastomatous tumors have respiratory difficulties [6], related to pleural, mediastinal, pulmonary or cervical masses [8].
Pearls and Pitfalls in the Imaging of Soft-Tissue Masses in Children
2020, Seminars in Ultrasound, CT and MRICitation Excerpt :On MRI, fibrous hamartoma of infancy is also often ill-defined and the appearance reflects the variable amounts of fat in relation to fibrous and mesenchymal tissue. The presence of intralesional striated pattern of hyperintense bands of fatty tissue alternating with isointense bands when compared with muscle is suggestive of this entity.6-8 This pattern is better recognized on T1-weighted images (Fig. 8).
A Typical Case of Lipoblastoma on the Lower Limb of an Infant
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The author has nothing to disclose.