Lipofibromatosis: magnetic resonance imaging features and pathological correlation in three cases

Lipofibromatosis arising in a right labiocrural fold in a 14-month-old female: a case report study with a 3-year follow-up

Lipofibromatosis (LF) is a rare benign fibrofatty tumor of infancy and childhood with a predilection for distal extremities, poor margination, and a high local recurrence rate. We report a toddler who presented with an LF involving her right labiocrural fold. Imaging showed a soft tissue mass extending through the right labiocrural fold with possible infiltration into the underlying muscles. The mass was excised entirely, preserving adjacent structures. The histopathologic report revealed the mass to be LF. A 3-year follow-up revealed no disease recurrence. No other cases of LF in this localization have been presented in the literature. Despite its rarity, LF should be considered in diagnosing soft tissue neoplasms in children. Accurate diagnosis and proper surgical management with complete resection are essential to reduce the postoperative recurrence risk.

Fat-Containing Soft Tissue Tumors in Children, Adolescents, and Young Adults: Which Require Biopsy?

PURPOSE

To confirm the overall benignity of fat-containing soft tissue tumors (STT) on a pediatric cohort and to define the clinical and imaging features that warrant a biopsy.

METHODS

A retrospective monocentric study was conducted on patients aged less than 25 years consecutively referred for fat-containing STT to our Comprehensive Cancer Center between 1998 and 2022. Tumor imaging characteristics at diagnosis (US, CT, or MRI) were correlated with pathology.

RESULTS

The database extraction identified 63 fat-containing tumors with clinical, histologic, and imaging data available for review. In total, 58 (92%) were benign tumors: 36 lipoblastomas and lipomas, 12 fibrous hamartomas of infancy (FHI), 5 lipofibromatosis, 2 lipomas arborescens, 2 lipomatosis and 1 spindle-cell lipoma. Five patients (8%) were diagnosed with liposarcoma. Factors significantly correlated with malignancy were age >10 years old (p < 0.001), having a cancer-predisposing condition (p < 0.001), a percentage of fat <25% (p = 0.002), and a presence of myxoid zones (p < 0.001) on imaging.

CONCLUSION

Most fat-containing STT in children may be classified as benign tumors based on clinics and imaging. The indication for biopsy could be limited to patients aged 10 years or more with either a cancer-predisposing condition or imaging features demonstrating either a low-fat component (<25%) or the presence of myxoid zones.

Lipofibromatosis: Central Nervous System Involvement by a Benign Neoplasm

Background: Lipofibromatosis is a relatively new entity, considered in the differential diagnosis of soft tissue tumors in children, involving mainly the extremities. Most cases can be completely resected without recurrence. Atypical forms have been described and their highly infiltrative capability can lead to severe clinical impairment. Case report: We report an infant with rapidly growing posterior cervicothoracic tumor, extending from the bulbo-medullary junction to T6 vertebra, leading to loss of spontaneous breathing, quadriparesis and devastating long-term consequences. Spinal tomography scan at 35 days suggested myelomeningocele. Prenatal and early postnatal ultrasounds were reviewed and no central nervous system involvement or fusion defects were present. Magnetic resonance at 40 days showed infiltrative mass, later confirmed by pathology as lipofibromatosis. Two resections failed to completely remove the tumor. Discussion: Lipofibromatosis can involve critical structures in the central nervous system and is difficult to treat surgically in those circumstances.

Update of pediatric soft tissue tumors with review of conventional MRI appearance-part 1: tumor-like lesions, adipocytic tumors, fibroblastic and myofibroblastic tumors, and perivascular tumors

There are numerous soft tissue tumors and tumor-like conditions in the pediatric population. Magnetic resonance imaging is the most useful modality for imaging these lesions. Although certain soft tissue lesions exhibit magnetic resonance features characteristic of a specific diagnosis, most lesions are indeterminate, and a biopsy is necessary for diagnosis. We provide a detailed update of soft tissue tumors and tumor-like conditions that occur in the pediatric population, emphasizing each lesion's conventional magnetic resonance imaging appearance, using the recently released 5th edition of the World Health Organization Classification of Soft Tissue and Bone Tumors as a guide. In part one of this review, pediatric tumor-like lesions, adipocytic tumors, fibroblastic and myofibroblastic tumors, and perivascular tumors are discussed. In part two, vascular lesions, fibrohistiocytic tumors, muscle tumors, peripheral nerve sheath tumors, tumors of uncertain differentiation, and undifferentiated small round cell sarcomas are reviewed. Per the convention of the WHO, these lesions involve the connective, subcutaneous, and other non-parenchymatous-organ soft tissues, as well as the peripheral and autonomic nervous system.

Giant dorsal lipofibromatosis in an infant: a case report

BACKGROUND

Lipofibromatosis is a rare, benign, soft tissue tumor that usually presents in children. Low incidence and lack of specificity in clinical presentation make its diagnosis difficult.

CASE PRESENTATION

This is a case report of a patient with a giant lipofibromatosis on the back that resembles an infantile hemangioma, which posed great difficulty in diagnosis due to atypical clinical manifestations. After the postoperative pathological and immunohistochemical examination and fluorescence in situ hybridization, the patient was finally diagnosed with lipofibromatosis.

CONCLUSIONS

The incidence of fibromatosis was low. This case presents an atypical clinical manifestation since the tumor growth was on the back, and this can easily cause misdiagnosis. This case suggests that the diagnosis of lipofibromatosis depends on the pathology and fluorescence in situ hybridization.

Orbital Lipofibromatosis in a Pediatric Patient

A 10-month-old boy presented with a 3-month history of progressive left lower eyelid swelling. Examination demonstrated left lower eyelid fullness and hyperglobus with a fatty appearing inferior fornix mass. Imaging showed a mass isointense to fat in the left lower eyelid extending posteriorly, surrounding the inferior oblique with complete fatty infiltration, obscuration of the inferior rectus, and adherence to the globe. The patient underwent orbitotomy with biopsy and debulking of the tumor. Surgical pathology showed multiple fragments of adipose tissue with foci of plump and spindle-shaped cells arranged in bundles and fascicles, consistent with lipofibromatosis. This case illustrates a rare presentation of orbital lipofibromatosis in a pediatric patient.

Strengthening the association of lipomatosis of nerve and nerve-territory overgrowth: a systematic review

OBJECTIVE

Lipomatosis of nerve (LN) is a massive enlargement of a nerve due to abundant proliferation of adipose and fibrotic tissue within the epineurium—part of the spectrum of adipose lesions of nerves, including intra- and extraneural lipomas. LN has been frequently associated with soft-tissue and/or osseous overgrowth. Unfortunately, much confusion exists since many names have been used for LN (e.g., fibrolipomatous hamartoma, macrodystrophia lipomatosa, and so on). To better understand this condition and to evaluate its association with nerve-territory overgrowth, the authors attempted to compile the world’s literature on published LN cases.

METHODS

PubMed and Google Scholar databases were searched to identify published articles on LN cases, using a variety of terms. Publications in all languages were assessed. All publications with cases determined likely to be LN were read. Cases that provided clear clinicopathological and/or radiological evidence of LN were labeled as “definite” and cases that demonstrated features of LN (e.g., nerve-territory overgrowth) but lacked definite proof of nerve involvement were labeled as “probable.”

RESULTS

Initial screening revealed a total of 2465 papers. After exclusions, 281 publications reported cases with a definite diagnosis of LN and 120 articles reported cases with a probable diagnosis of LN. The authors identified 618 definite and 407 probable cases of LN. Sex distribution was balanced (51% female). Early diagnosis was common, with two-thirds of patients having symptoms in the 1st decade of life. The most commonly affected nerve was the median nerve (n = 391). Nerve-territory overgrowth was common (62% definite LN; 78% combined cases); overgrowth was exclusive to the territory of the affected nerve in all cases but 5.

CONCLUSIONS

The authors present a comprehensive review and analysis of the literature of LN cases. One of the main findings was the nerve-territory overgrowth was associated with LN, especially when present earlier in life. The authors believe that all cases of LN associated with overgrowth can be explained on anatomical grounds, even in the few reported cases in which this is not immediately obvious.

Lipofibromatosis

Introduction: Lipofibromatosis is a benign pediatric soft tissue tumor arising preferentially in the distal extremities. Histologically, the tumor shows abundant adipose tissue admixed with a spindle cell component, often concentrated in septal and perimysial locations. The index case is being presented to discuss the histopathological and immunohistochemical clues to differentiate it from other fibrofatty tumors of childhood.Case report: An 11-month-old male child presented with a slowly growing mass on the upper back. MRI findings were suggestive of an adipocytic tumor. Microscopy revealed a lesion composed of mature adipocytes and intervening fibrous bands with infiltration into the adjacent skeletal muscle, features of lipofibromatosis.Conclusion: Lipofibromatosis should be considered in the differential diagnosis of a pediatric fibrofatty tumor. Accurate diagnosis is essential for proper patient management as incomplete removal of the tumor may result in recurrence.

Aberrant receptor tyrosine kinase signaling in lipofibromatosis: a clinicopathological and molecular genetic study of 20 cases

Lipofibromatosis is a rare pediatric soft tissue tumor with predilection for the hands and feet. Previously considered to represent "infantile fibromatosis", lipofibromatosis has distinctive morphological features, with mature adipose tissue, short fascicles of bland fibroblastic cells, and lipoblast-like cells. Very little is known about the genetic underpinnings of lipofibromatosis. Prompted by our finding of the FN1-EGF gene fusion, previously shown to be a characteristic feature of calcifying aponeurotic fibroma (CAF), in a morphologically typical case of lipofibromatosis that recurred showing features of CAF, we studied a cohort of 20 cases of lipofibromatosis for this and other genetic events. The cohort was composed of 14 males and 6 females (median age 3 years; range 1 month-14 years). All primary tumors showed classical lipofibromatosis morphology. Follow-up disclosed three local recurrences, two of which contained calcifying aponeurotic fibroma-like nodular calcifications in addition to areas of classic lipofibromatosis, and no metastases. By FISH and RNA sequencing, four cases were positive for FN1-EGF and one case each showed an EGR1-GRIA1, TPR-ROS1, SPARC-PDGFRB, FN1-TGFA, EGFR-BRAF, VCL-RET, or HBEGF-RBM27 fusion. FN1-EGF was the only recurrent fusion, suggesting that some cases of "lipofibromatosis" may represent calcifying aponeurotic fibroma lacking hallmark calcifications. Several of the genes involved in fusions (BRAF, EGFR, PDGFRB, RET, and ROS1) encode receptor tyrosine kinases (RTK), or ligands to the RTK EGFR (EGF, HBEGF, TGFA), suggesting a shared deregulation of the PI3K-AKT-mTOR pathway in a large subset of lipofibromatosis cases.

Infiltrating angiolipoma of the foot: magnetic resonance imaging features and review of the literature

Angiolipoma is a benign soft tissue tumor with two subtypes: non-infiltrating and infiltrating. Although histologically benign, infiltrating angiolipoma can invade surrounding structures. The foot is a very rare location for angiolipoma, with only four cases reported in the English literature, including one infiltrating type. Here, we report a very rare case of infiltrating angiolipoma of the foot with magnetic resonance imaging (MRI) and ultrasonography (US) findings. A 7-year-old boy presented with a slowly growing foot mass. MRI showed an unencapsulated mass involving the third web space extending to the foot dorsum and sole. The mass was isointense to subcutaneous fat and was mixed with internal T1 low-signal-intensity enhancing areas. On US, we observed a heterogeneously hypoechoic mass with internal vascularity. Imaging and clinical features of angiolipoma and the radiologic differential diagnoses of a fat-containing mass in the pediatric foot are reviewed here. When there is an ill-defined foot mass with a fat component and variable enhancing portions in a child, infiltrating angiolipoma should be included in the differential diagnosis along with other fat-containing tumors.

Imaging appearances of soft-tissue tumors of the pediatric foot: review of a 15-year experience at a tertiary pediatric hospital

Tumors of the foot are rare in children. In this review the authors illustrate radiographic, sonographic and MR imaging findings of foot soft-tissue tumors in children based on all cases presenting at a tertiary pediatric hospital during the 15-year period of 1999-2014. Among these cases there were 155 tumors of the foot - 72 of the bones and 83 of the soft tissues. Vascular malformations, fibromatosis and sarcomas were respectively the most frequent benign, intermediate and malignant soft-tissue tumors. Some tumors showed specific imaging findings. In imaging investigations, ultrasound can be used as the first imaging modality for diagnostic workup of most lesions because it is noninvasive, low-cost and readily available, and can confirm the presence of the mass and evaluate cystic components, especially in young children who would otherwise require sedation for MR imaging. MR imaging is the reference standard technique because of its high tissue contrast, which allows for detection and characterization of soft-tissue and bone abnormalities. MR imaging is useful as the first imaging modality in select cases, including those with high suspicion of malignancy, very large lesions or pre-treatment lesions. Recognition of some typical imaging findings in pediatric soft-tissue foot tumors is helpful to establish diagnosis and facilitate patient management.

Fat-containing soft-tissue masses in children

The diagnosis of soft-tissue masses in children can be difficult because of the frequently nonspecific clinical and imaging characteristics of these lesions. However key findings on imaging can aid in diagnosis. The identification of macroscopic fat within a soft-tissue mass narrows the differential diagnosis considerably and suggests a high likelihood of a benign etiology in children. Fat can be difficult to detect with sonography because of the variable appearance of fat using this modality. Fat is easier to recognize using MRI, particularly with the aid of fat-suppression techniques. Although a large portion of fat-containing masses in children are adipocytic tumors, a variety of other tumors and mass-like conditions that contain fat should be considered by the radiologist confronted with a fat-containing mass in a child. In this article we review the sonographic and MRI findings in the most relevant fat-containing soft-tissue masses in the pediatric age group, including adipocytic tumors (lipoma, angiolipoma, lipomatosis, lipoblastoma, lipomatosis of nerve, and liposarcoma); fibroblastic/myofibroblastic tumors (fibrous hamartoma of infancy and lipofibromatosis); vascular anomalies (involuting hemangioma, intramuscular capillary hemangioma, phosphate and tensin homologue (PTEN) hamartoma of soft tissue, fibro-adipose vascular anomaly), and other miscellaneous entities, such as fat necrosis and epigastric hernia.