Lipofibromatosis: an institutional and literature review of an uncommon entity

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.

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.

Pediatric Lymphedema: Study of 180 Patients Referred to a Tertiary Lymphedema Clinic

BACKGROUND

Lymphedema is due to dysfunction of the lymphatic system. It can be primary or secondary. Pediatric lymphedema is more often primary and is a chronic disease with a heavy burden on quality of life.

METHODS

Medical records of patients under 18 years of age referred between 1996 and 2021 to the specialized lymphedema clinic at the Sainte-Justine University Hospital Center were reviewed. Demographic data, sex, age at presentation, location of the lymphedema, clinical features, genetic testing, symptoms, complications, investigations, and treatment were collected.

RESULTS

Of 180 referred patients, lymphedema was confirmed in 151, and 137 were primary lymphedema. Median age of apparition of primary lymphedema was 7.00 years and was significantly lower in boys than in girls. Primary congenital lymphedema was more frequent in boys (51.0%, 27.3% in girls, P = .007), and onset of primary lymphedema during adolescence was more frequent in girls (53.4%, 25.0% in boys, P = .001). Lower limbs were the most impacted (88.3%). Sixty patients had genetic testing, and 38 (63.3%) of them were discovered to have a pertinent genetic mutation. The most common mutated gene was the FLT4 gene (in 9 patients). Seven patients (5.1%) had associated extensive/central lymphatic malformation and 24 (17.6%) had a polymalformative syndrome/syndromic lymphedema.

CONCLUSIONS

Pediatric lymphedema is more frequent in girls, usually involves lower limb, and is most often sporadic, but often associated with a genetic mutation, and genetic testing should be performed.

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.

Successful Limb-Sparing Wide Excision of a Giant Lipofibromatosis in a 5-Year-Old Girl

A 5-year-old girl presented with a big painless mass, sized 24 × 37 × 35 cm, in her lower left limb. MRI revealed a huge heterogeneous mass splaying from the left distal femur to the calcaneal region without bony erosion but compressing the arteries and causing bowing of the left tibia and fibula bones. The difficulty was to determine the best course of action taken which would either be limb salvation or amputation. Considering that only a few muscles could be saved, the author initially recommended amputation but still considered a limb-sparing procedure. After a double set-up examination in the operating room, the author ultimately decided to save the affected limb. The salvaged limb was found to be viable after the surgery, and there was no further recurrence over a subsequent 6-month follow-up period. The careful surgical decision is vital in giving the best possible care to the patient.

Nonepithelial Tumors and Tumor-like Lesions of the Skin and Subcutis in Children

This overview of mesenchymal tumors presenting in the skin and/or subcutis in children brings together the range of neoplasms and hamartomas which are seen in this age-group. It is not surprising from the perspective of the pediatric or general surgical pathologist that vascular anomalies, including true neoplasms and vascular malformations, are the common phenotypic category. Since there is considerable morphologic overlap among these lesions, clinicopathologic correlation may be more important than for many of the other mesenchymal tumors. The skin and subcutis are the most common sites of clinical presentation for the infantile myofibroma which is the most common of fibrous mesenchymal tumors in children. Several of the other mesenchymal tumors are more common adults-like dermatofibrosarcoma protuberans, but nonetheless have an important presence in children, even as a congenital neoplasm. A lipomatous tumor in a young child should be considered as a possible manifestation of an overgrowth syndrome.

Lipofibromatosis-like neural tumor: Case report of a unique infantile presentation

A 14-month-old boy presented with a slow-growing, asymptomatic back plaque, which was biopsied and found to have S100 positivity, sparse CD34 staining, and no significant mitotic activity, nuclear pleomorphism, or necrosis; genetic workup found LMNA-NTRK1 gene fusion, overall consistent with lipofibromatosis-like neural tumor (LPF-NT). LPF-NT is rare, with 14 cases previously reported, and our patient is the first report of this diagnosis in infancy. This case report and literature review includes comparison of similar diagnoses including lipofibromatosis, low-grade malignant peripheral nerve sheath tumor, infantile fibrosarcoma, and dermatofibrosarcoma protuberans and serves to aid detection of LPF-NT presenting in pediatric patients by highlighting similarities and differences that should prompt consideration. LPF-NT shows locally aggressive behavior only and should not be confused with conditions that have potential for distant spread. However, case reports of metastasizing LMNA-NTRK1 tumors draw into question whether growths with this gene fusion exist on a spectrum of disease severity. Our patient was treated with wide local excision and has developed no complications or evidence of recurrence with 6 months of follow-up time.

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.