Lipoblastoma: better termed infantile lipoma?

Submandibular lipoblastoma: Case report of a rare tumor in childhood

Lipoblastoma is a rare, benign tumor usually occurring in childhood. It is essentially localized in the extremities and trunk, with few cases reported in the neck. We report the case of a 2-year-old girl with a rapidly enlarging, painless neck mass. Magnetic resonance imaging (MRI) revealed a 3-cm mass in the right submandibular region. Review of literature, diagnostic methods, and genetics of lipomatous tumors are discussed. Complete surgical excision via a lateral cervical approach demonstrated a white soft tissue with an adherent ganglion. Histology and immunohistochemistry confirmed the diagnosis of lipoblastoma. Cervical lipoblastoma is rare, and typically asymptomatic, rarely causing nerve compression or airway obstruction. MRI can help identifying the lipomatous nature of the mass, but the findings can be inconsistent due to variable maturity of fat cells and the mesenchymal content of the tumor. Diagnosis is always based on pathological examination. Further chromosomal analysis is useful in differentiating lipoblastoma from liposarcoma. Complete surgical excision is the recommended treatment.

Lipoblastoma: computed tomographic and magnetic resonance imaging features correlate with tumor behavior and pathology

BACKGROUND

Lipoblastoma is a rare benign neoplasm of immature fat cells in children. Imaging appearances are frequently complex, sometimes simulating liposarcoma.

OBJECTIVE

To characterize features of lipoblastoma on MRI and CT in comparison with recurrence risk.

MATERIALS AND METHODS

We identified cases via retrospective review of histopathology-proven lipoblastoma cases in a large referral database and a pediatric medical center. Two radiologists scored CT and MRI on the basis of lesion features.

RESULTS

We included a total of 56 children (32 boys and 24 girls) with a mean age of 2.6 years (range 0.1-13 years). Extremity lesions were most common (27%), followed by neck (19%), gluteal region (18%), chest (14%) and mesentery (14%). Children most commonly presented with painless masses (73%), followed by dyspnea (9%), distension (9%) and pain (7%). Non-adipose soft-tissue components were identified on CT and MRI in 78% of cases. Significant (moderate or marked) septations were noted in 59% and enhancement in 35%. Compartmental invasion was present in 43% of cases. Of paraspinal cases, 38% involved the neural foramina or central canal. Lesion complexity did not significantly correlate with age. Recurrence was observed in 9% of cases and was significantly correlated with compartmental invasion (correlation: 0.303, P=0.009) and septation complexity (correlation: 0.227, P=0.038) on initial imaging.

CONCLUSION

Although lipoblastoma is a fat-containing entity, many lesions demonstrate marked complexity and local infiltration that resemble liposarcoma, which is exceedingly rare in younger children. Compartmental invasion and thicker septations appear to confer greater risk of recurrence following resection.

A Rare Case of Giant Mesenteric Lipoblastoma in a 6-Year-Old Child and Review of the Literature

Giant mesenteric lipoblastoma is a rare benign tumor arising from the adipocytes. It can mimic malignant tumors, and its diagnosis is difficult before surgery. Imaging studies could lead the diagnosis but not confirm it. Those tumors arising in the abdomen are usually larger and can cause symptoms of compression. Surgical excision is the treatment of choice, and a long-term follow-up is necessary to detect local recurrences. Only a few cases of lipoblastomas arising from the mesentery are reported in literature. We present a case of a rare giant lipoblastoma arising from the mesentery of a 6-year-old girl, with a history of postprandial abdominal pain.

A Giant Childhood Mesenteric Lipoblastoma With Extensive Maturation

Abdominal lipoblastomas are uncommon soft tissue tumors in children and rarely arise from the mesentery. Due to intraabdominal location and slow growth, these masses can go unnoticed for long periods of time and often found on surgical exploration. We present a case of a 12-year-old male with years of abdominal distension accompanied by new onset early satiety that was found to have an intra-abdominal mass. He underwent an exploratory laparotomy revealing a large 33 x 27 x 15 cm rubbery mesenteric mass displacing the entire intra-abdominal contents, connected by a single vascular pedicle and encasing a loop of small intestine. The mass was resected and the patient did well without signs of recurrence. Histology confirmed the presence of mature adipocytes but on further cytogenetic analysis, a translocation between chromosomes 2 and 8 at the 12q arm was detected, which is often associated with lipoblastomas. This case represents the one of the largest mesenteric lipoblastomas that matured extensively to lipoma-like histology at the time of surgical resection.

Robotic resection of recurrent pediatric lipoblastoma

This case demonstrates successful resection of a rare, recurrent presacral-pelvic lipoblastoma in a 19-year-old female patient. Because of the anatomical location of the mass and its proximity to vital structures, the robotic approach allowed for both optimal visualization and effective debulking of the mass. Furthermore, with the use of an articulating laparoscopic camera, key visualization of the posterior lateral pelvis was possible. Using a wide breadth of technologies and resources is essential to broadening the surgical armamentarium and achieving resectability in otherwise challenging cases.

A Giant Deep-seated Lipoma in a Child's Forearm

Deep-seated giant lipomas are rare relative to the overall incidence of the tumor and their occurrence grows more frequent with age. A case of an unusual deep-seated giant lipoma in the forearm of a four-year-old child is reported.

Giant Mediastinal Lipoblastoma

A 3-year-old girl with fever, increasing cough, and nasal discharge for 2 weeks, was found to have a giant mediastinal lipoblastoma. The tumor weighing 556 g was successfully resected.

Mesenteric lipoblastoma presenting as a small intestinal volvulus in an infant: A case report and literature review

A 1-year-old boy with no underlying disorder presented with non-bilious vomiting since 4 days before admission. He was referred to our hospital and was diagnosed with a small bowel obstruction due to an intraabdominal tumor. Laparotomy revealed an intestinal volvulus with a soft and lobulated tumor arising from the mesentery. The resected tumor with a small part of the small bowel was diagnosed as lipoblastoma histologically. From a literature review, mesenteric lipoblastoma with an intestinal volvulus showed different characteristics such as greater frequency of vomiting and less frequency of abdominal mass as clinical symptoms, and the size of the tumor was smaller than that of the tumor without the intestinal volvulus.

A rare case of inguinolabial lipoblastoma in a 13-month-old female

Lipoblastoma is a rare, rapidly growing, benign mesenchymal tumor composed of various stages of maturing adipocytes that most often occurs in children under the age of 3. The common locations are the extremities and the trunk. Presentation in the genitoinguinal area is rare. We report a case of a 13-month-old female infant with a 4-month history of a progressively enlarging left labial mass that encompassed her left labium majora and inguinal region. Pelvic MRI confirmed growth from previous ultrasound size of 3 × 2 × 1 cm to 7 × 2 × 2 cm. Composition was suggestive of adipose tissue. The mass was excised through a left inguinal incision. The final pathology results described a lipoblastoma. Six year follow-up has not revealed any signs or symptoms of recurrence. Circumscribed lipoblastomas should be distinguished from their infiltrative counterpart, diffuse lipoblastoma or lipoblastomatosis, which can be more difficult to excise and thus, more likely to recur. Lipoblastoma should also be distinguished from myxoid liposarcoma, which has malignant features, carries a high risk of recurrence, and requires a more aggressive management protocol. Although rare, lipoblastoma should be considered as part of the differential diagnosis of a rapidly growing vulvar mass in prepubertal children.

Rearrangement of HMGA2 in a case of infantile lipoblastoma without Plag1 alteration

Lipoblastoma is a rare benign adipocytic tumor that occurs usually in children. It can be difficult to distinguish a lipoblastoma from other lipogenic tumors. In such cases, the detection of a rearrangement of the PLAG1 gene by fluorescence in situ hybridization analysis is useful for characterizing a lipoblastoma. We present here a novel case of morphological infantile lipoblastoma showing a rearrangement of HMGA2 instead of the classical PLAG1 alteration. HMGA2 is the main target of clonal aberrations encountered in lipomas. This result supports the hypothesis that benign lipomatous tumors harboring PLAG1 or HMGA2 rearrangement could constitute a unique pathogenetic entity.

Benign intrascrotal lipoblastoma in a 4-month-old infant: a case report and review of literature

Lipoblastomas are rare benign soft tissue tumors that occur primarily in young children. Most lipoblastomas occur in the extremities, trunk, head, and neck. An intrascrotal location is unusual. We describe a case of a 4-month-old infant with an intrascrotal lipoblastoma and discuss the differential diagnosis and review the literature.

Lipoblastoma with unique localization requiring tracheal and esophageal resection

Lipoblastoma and lipoblastomatosis are rare tumors of infancy. They originate from embryonic fat and localize in soft tissues. We present the case of a lipoblastoma of the neck with localization in tracheal and esophageal walls that required an extended laryngotracheal and esophageal resection. To our knowledge, this is the first report of such localization of this tumor.

Imaging of the unusual pediatric 'blastomas'

‘Blastomas’ are tumors virtually unique to childhood. Controversy surrounds their nomenclature and there is no globally accepted classification. They are thought to arise from immature, primitive tissues that present persistent embryonal elements on histology, affect a younger pediatric population and are usually malignant. The ‘commoner’ blastomas (neuroblastoma, nephroblastoma, hepatoblastoma, medulloblastoma) account for approximately 25% of solid tumors in the pediatric age range. We present examples of the more unusual blastematous pediatric tumors (lipoblastoma, osteoblastoma, chondroblastoma, hemangioblastoma, gonadoblastoma, sialoblastoma, pleuropulmonary blastoma, pancreatoblastoma, pineoblastoma, and medullomyoblastoma) that were recorded in our institution. Although these rare types of blastomas individually account for <1% of pediatric malignancies, collectively they may be responsible for up to 5% of pediatric tumors in a given population of young children. Imaging is often non-specific but plays an important role in their identification, management and follow-up. Some characteristic imaging features at diagnosis, encountered in cases diagnosed and treated in our institution, are described and reviewed.

Mesenteric lipoblastoma presenting as a segmental volvulus

Mesenteric lipoblastoma is a rare tumor and, its presentation as a bowel obstruction with possible midgut volvulus has only been reported once before. A 7-year-old girl presented with nausea and vomiting but a benign abdominal examination. Upper gastrointestinal contrast study demonstrated possible malrotation with midgut volvulus. During emergency laparotomy, segmental small bowel volvulus secondary to a large mesenteric lipoblastoma was found. The lipoblastoma was resected with a segment of small bowel. Resection margins were negative for tumor, and the patient is doing well with no evidence of recurrence.

Differential diagnosis of lipoma-like lipoblastoma

Lipoblastomas are rare benign tumors of white fatty tissue that occur primarily in young children. Occasionally, heterogeneity of morphological appearance and histological overlap with other lipogenic tumors are described. In such cases fluorescence in situ hybridization (FISH) analysis of PLAG1, a gene specifically rearranged in lipoblastoma, is necessary to prevent misdiagnosis. We present a case of lipoblastoma arising in an atypical site with histological features characteristic of lipoma. The correct diagnosis was made possible on cytogenetic grounds through the identification of the characteristic PLAG1-HAS2 fusion gene, thus allowing an appropriate clinical approach.

Mesenteric lipoblastoma: a rare location in children

Lipoblastoma is a rare childhood tumor composed of embryonic fat. It is benign and most often presents in children younger than 3 years. These tumors primarily present as a rapidly enlarging mass in the extremities or trunk with abdominal lipoblastomas comprising less than 10% of all reported cases. Abdominal lipoblastomas are most commonly found in the retroperitoneum with less than 15 reported cases arising in the mesentery. We report the unusual presentation of a lipoblastoma arising in the mesentery of a 3-year-old boy.

Lipoblastoma arising from the submandibular region

A lipoblastoma is a rare, benign tumor arising from embryonic white fat. The tumors occur primarily in infancy and early childhood and commonly arise from the limbs and the trunk, but neck involvement is extremely rare. Our case arose in a 22-month-old male presenting with a rapidly enlarging soft mass in the right submandibular area. Lipoblastoma was diagnosed by histologic evaluation, the mass was completely removed, and there was no recurrence at 1-year follow-up.

Cervical lipoblastoma: Case report, review of literature, and genetic analysis

BACKGROUND

Lipoblastoma is a rare, benign tumor of infants and children, usually occurring in the extremities and trunk, with only a few cases reported in the neck.

METHODS

We describe the case of an infant with a rapidly enlarging, painless neck mass. MRI revealed a 4-cm-diameter mass deep to the paraspinal muscles, in close proximity to the C2 vertebral foramen. Review of literature, diagnostic methods, and genetics of lipomatous tumors are discussed.

RESULTS

Complete surgical excision via a posterior cervical approach demonstrated irregular lobules of immature fat cells separated by a loose, myxoid connective tissue. Histology and genetic analysis confirmed the diagnosis of lipoblastoma.

CONCLUSION

Cervical lipoblastoma is rare, and typically presents as an asymptomatic, painless mass, rarely causing airway obstruction or nerve compression. MRI can be helpful in identifying the lipomatous nature of the mass, but the findings can be inconsistent due to variable maturity of fat cells and the mesenchymal content of the tumor. Chromosomal analysis is useful in differentiating lipoblastoma from liposarcoma. Recommended treatment is complete surgical excision.

Intrapelvic lipoblastoma with massive spinal canal invasion

OBJECTS

The lipoblastoma is a rare benign pediatric neoplasm that derives from embryonic white fat cells. However, this tumor with spinal invasion in children is extremely rare. We report a case of a 3-year-old boy who had lipoblastoma with massive invasion into the lower lumbosacral spinal canal.

CASE REPORT

A 3-year-old boy had suffered from progressive urinary incontinence and uncontrolled defecation during past 3 months. Computed tomography and magnetic resonance imaging scans showed that a large lobulated pelvic cavity mass had invaded the lumbosacral spinal canal. The mass was located over the epidural space from L4 to the lower sacral spinal canal, resulting in the compression of the thecal sac. After total laminectomy from L4 to S3 with flavectomy, a subtotal mass removal for the intraspinal canal mass was done. Histopathologic diagnosis confirmed the lipoblastoma.

CONCLUSION

Lipoblastoma is a rare benign neoplasm and lumbosacral invasion is unique. Complete surgical excision is the treatment of choice. If an incomplete surgical excision is performed, close observation and clinical follow-up must be done because a recurrence is possible.

Intrascrotal lipoblastoma: a case report and review of the literature

Lipoblastomas are rare benign soft tissue tumors that occur primarily in young children. Most lipoblastomas occur in the extremities, trunk, head, and neck. An intrascrotal location is unusual. We describe the case of a 4-year-old boy with an intrascrotal lipoblastoma and discuss the differential diagnosis in reviewing the literature.

[Intrathoracic lipoblastoma with costal involvement]

We report the case of a two-year-old girl with a lipoblastoma arising from the chest wall with intrathoracic extension and costal involvement. The diagnosis was confirmed histologically after surgery. Plain-film chest x-rays showed an extrapleural mass; computed tomography (CT) and magnetic resonance imaging (MRI) suggested fatty contents. The differential diagnosis is mainly versus liposarcoma, which is extremely rare in children.

MRI findings of an intermuscular lipoma in a 2-year-old

We report the MRI findings of a large deep intermuscular lipoma in a 2-year-old child with a painless palpable shoulder mass, and its differentiation from liposarcoma and other soft-tissue masses. To our knowledge, the imaging features of deep lipomas in children have not been reported.

Rearrangement of chromosomal region 8q11-13 in lipomatous tumours: correlation with lipoblastoma morphology

Cytogenetics is of considerable value when diagnosing lipomatous tumours, as different tumour types have different more or less specific chromosomal abnormalities. One such entity is lipoblastoma, which is a benign lipomatous tumour that often exhibits rearrangements of chromosome bands 8q11-13, and the gene PLAG1 has been implicated as the target of these chromosomal changes. All lipomatous tumours karyotyped at the Norwegian Radium Hospital were reviewed, looking for rearrangements of 8q11-13. Five tumours exhibiting chromosomal abnormalities affecting this region were found. Only one of them was morphologically diagnosed as a lipoblastoma, two being classified as lipomas, one as a hibernoma, and one as a well-differentiated liposarcoma. The two tumours successfully analysed with bacterial artificial chromosomes (BACs) covering the gene PLAG1 showed involvement of this gene in the rearrangement. The findings raise the question as to what extent the diagnosis lipoblastoma should be based on histopathological or cytogenetic/molecular data or a combination thereof. When karyotypic information from this series was combined with available literature data, it was found that the sensitivity of 8q11-13 rearrangements for diagnosing lipoblastomas when found in a lipomatous tumour was 77% and that the corresponding specificity was 98%. The validity of these calculations of the diagnostic information provided by the cytogenetic findings is, of course, totally dependent on the morphological diagnosis made in each case. Regardless of what the precise phenotypic diagnosis was, it is suggested that lipomatous tumours with 8q11-13 rearrangement constitute a distinct pathogenetic entity. When selective therapies tailor-made against the specific pathogenetic rearrangement become available, it will become mandatory to pay more attention to the genetic constitution of the tumour cells than to their phenotypic appearance.

From the archives of the AFIP: benign musculoskeletal lipomatous lesions

Benign lipomatous lesions involving soft tissue are common musculoskeletal masses that are classified into nine distinct diagnoses: lipoma, lipomatosis, lipomatosis of nerve, lipoblastoma or lipoblastomatosis, angiolipoma, myolipoma of soft tissue, chondroid lipoma, spindle cell lipoma and pleomorphic lipoma, and hibernoma. Soft-tissue lipoma accounts for almost 50% of all soft-tissue tumors. Radiologic evaluation is diagnostic in up to 71% of cases. These lesions are identical to subcutaneous fat on computed tomographic (CT) and magnetic resonance (MR) images and may contain thin septa. Lipomatosis represents a diffuse overgrowth of mature fat affecting either subcutaneous tissue, muscle or nerve, and imaging is needed to evaluate lesion extent. Lipoblastoma is a tumor of immature fat occurring in young children, and imaging features may reveal a mixture of fat and nonadipose tissue. Angiolipoma, myolipoma, and chondroid lipoma are rare lipomatous lesions that are infrequently imaged. Spindle cell and pleomorphic lipoma appear as a subcutaneous lipomatous mass in the posterior neck or shoulder, with frequent nonadipose components. Hibernoma appears as a lipomatous mass with serpentine vascular elements. Benign lipomatous lesions affecting bone, joint, or tendon sheath include intraosseous lipoma, parosteal lipoma, liposclerosing myxofibrous tumor, discrete lipoma of joint or tendon sheath, and lipoma arborescens. Intraosseous and parosteal lipoma have a pathognomonic CT or MR appearance, with fat in the marrow space or on the bone surface, respectively. Liposclerosing myxofibrous tumor is a rare intermixed histologic lesion commonly located in the medullary canal of the intertrochanteric femur. Benign lipomatous lesions may occur focally in a joint or tendon sheath or with diffuse villonodular proliferation in the synovium (lipoma arborescens) and are diagnosed based on location and identification of fat. Understanding the spectrum of appearances of the various benign musculoskeletal lipomatous lesions improves radiologic assessment and is vital for optimal patient management.

Lipoblastoma in a four-year-old African child

A four-year old Sudanese child presented with a growing mass in the medial aspect of the right thigh. The mass appeared during the neonatal period. On clinical examination a diagnosis of lipoblastoma was entertained on the basis of the patient's age and the clinical features of the mass. The tumor was completely excised surgically. The clinical diagnosis of lipoblastoma was confirmed pathologically. Follow-up of the patient for 6 months postoperatively showed no evidence of recurrence.

Lipoblastoma of the neck: a case report and literature review

Lipoblastoma is a rare benign tumor arising from embryonic white fat. We describe a case of huge lipoblastoma of the neck in a 1-year-old boy. Magnetic resonance imaging (MRI) revealed a 7 x 7 cm neck mass that extruded into the parapharyngeal and paratracheal spaces. At the operation, a well-circumscribed and extensively growing tumor was completely removed. Histopathologic examination showed that the tumor contained lobulated mature adipose tissue and myxoid tissue with lipoblasts and other immature fat cells. The postoperative course was uneventful, and no recurrence of tumor has been noted in more than 2 years follow-up.

Diagnosing paediatric mediastinal lipoblastoma using ultrasound-guided percutaneous needle biopsy: review and report

Lipoblastoma is a rare tumor of embryonal fat occurring predominantly in the first three years of life. This benign tumor has potentials to local invasion and rapid growth. We reported a rare case of mediastinal lipoblastoma. The computed tomography (CT) and ultrasound (US) features, and the roles of percutaneous transthoracic US-guided needle biopsy, are discussed.

PLAG1 alterations in lipoblastoma: involvement in varied mesenchymal cell types and evidence for alternative oncogenic mechanisms

Lipoblastomas are rare soft tissue tumors that occur primarily in young children. They typically contain variably differentiated adipocytes, primitive mesenchymal cells, myxoid matrix, and fibrous trabeculae. Abnormalities in chromosome 8, leading to rearrangements of the PLAG1 gene, were demonstrated recently in four lipoblastomas. In the present report, we determine the frequency of PLAG1 alterations in 16 lipoblastomas from children aged 13 years or younger, and we also evaluate the stages of lipoblastoma differentiation at which PLAG1 genomic alterations are found. Eleven lipoblastomas (69%), including those with either classic or lipoma-like histology, had rearrangements of the 8q12 PLAG1 region. Another three lipoblastomas had polysomy for chromosome 8 in the absence of PLAG1 rearrangement. Only two cases (13%) lacked a chromosome 8 abnormality. Notably, the lipoblastomas with chromosome 8 polysomy had up to five copies of chromosome 8 as an isolated cytogenetic finding in an otherwise diploid cell. We also demonstrate that PLAG1 alterations are found in a spectrum of mesenchymal cell types in lipoblastomas, including lipoblasts, mature adipocytes, primitive mesenchymal cells, and fibroblast-like cells. This finding is consistent with neoplastic origin in a primitive mesenchymal precursor and with variable differentiation to a mature adipocyte end-point. Hence, our studies provide biological validation for the clinical observation that lipoblastomas can evolve into mature, lipoma-like, lesions. They also suggest that PLAG1 dosage alterations caused by polysomy 8 might represent an alternative oncogenic mechanism in lipoblastoma.