Cytogenetic analysis in the diagnosis and management of lipoblastomas: results from a single institution

Update of Pediatric Lipomatous Lesions: A Clinicopathological, Immunohistochemical and Molecular Overview

Lipomatous neoplasms are a rare entity in the pediatric population, comprising less than 10% of soft tissue tumors in the first two decades of life. Some characteristics of pediatric adipocytic tumors are analogous to their adult counterparts, some pediatric lipomatous lesions however harbor unique features. In recent years, there have been significant advances in the understanding of the pathogenesis and hence in the classification and treatment of pediatric adipocytic tumors. This literature-based article will provide a review of the presently known clinicopathological, immunohistochemical and molecular features of pediatric lipomatous lesions.

Giant axillary lipoblastoma in an African child: a case report

Background

Lipoblastoma is a rare benign neoplasm of the adipose tissue occurring most commonly in infants and young children. This tumor can present as a localized, well-circumscribed lesion (lipoblastoma) or as a multi-centric lesion (lipoblastomatosis).

Case presentation

This is a case report of lipoblastoma in a 19-month-old male with 9 months history of rapidly progressing axillary mass. Examination revealed a well-circumscribed right axillary mass measuring 25 cm × 20 cm with normal overlying skin and prominent, visibly distended superficial veins. He had surgical excision of the mass. Histologic examination revealed lipoblastoma. There has been no recurrence in the last 21 months of follow-up.

Conclusion

The report is presented for its rarity and also for its potential to pose diagnostic difficulty to surgeons. Surgical excision offers the best chance of cure. Long-term follow-up is also important to detect recurrence.

Advances in the Diagnosis and Management of Neonatal Sarcomas

Neonatal sarcomas comprise a heterogeneous group of rare soft tissue neoplasms that present unique diagnostic and therapeutic challenges. Recent advances in molecular profiling have improved diagnostic capabilities and reveal novel therapeutic targets. Clinical trials demonstrate differences in behavior between sarcoma subtypes that allow for better clinical management. Surgical resection has been replaced with a multimodal approach that includes chemotherapy and radiotherapy. Despite these advances, neonates with sarcoma continue to fare worse than histologically similar sarcomas in older children, likely reflecting differences in tumor biology and the complexities of neonatal medicine. This review focuses on recent advances in managing neonatal sarcomas.

Lipoblastomas presenting in older children and adults: analysis of 22 cases with identification of novel PLAG1 fusion partners

Lipoblastomas are benign neoplasms of embryonal white fat that typically present in the first 3 years of life and show a lobular arrangement of maturing adipocytes with variable degrees of myxoid change. We systematically studied the clinicopathologic and genetic features of lipoblastomas arising in older children and adults. Cases with a diagnosis of lipoblastoma or maturing lipoblastoma in patients >3 years of age were retrieved from our archives. Immunostaining for CD34 and desmin and molecular studies (FISH, RNA sequencing) were performed. Twenty-two cases (8F; 14M) were identified in patients ranging from 4 to 44 years of age (median 10 years). Sites included extremity (n = 15), head and neck (n = 4), and trunk (n = 3) with tumor sizes varying from 1.6 to 17.5 cm (median 5). Only three tumors had histologic features of "conventional" lipoblastoma. The majority of tumors (n = 14) were composed of variably sized lobules of mature adipose tissue partitioned by thin fibrous septa ("maturing"). The remaining five cases consisted predominantly of bland spindled to plump ovoid cells embedded in a fibrous stroma, with a vaguely plexiform arrangement of small myxoid and adipocytic nodules ("fibroblastic"). CD34 was diffusely positive in all cases tested (21/21), while desmin immunoreactivity was identified in 12 of 21 cases (diffuse = 7, focal = 5). PLAG1 rearrangements were identified in 13 tumors in the entire cohort (59%), including all 5 fibroblastic tumors. RNA sequencing detected eight PLAG1 fusion partners, of which two were known (CHCHD7 and COL3A1) and six were novel (SRSF3, HNRNPC, PCMTD1, YWHAZ, CTDSP2, and PPP2R2A). Twelve cases had follow-up (1-107 months; median 21 months), and no recurrences were reported. Lipoblastomas may occur in older children and adults and may be difficult to recognize due to their predominantly adipocytic or fibrous appearance. Awareness that lipoblastomas may occur in older patients, careful evaluation for foci showing more typical morphologic features, ancillary immunohistochemistry for CD34 and desmin, and molecular genetic studies to identify PLAG1 rearrangements are the keys to recognizing these tumors.

BISTRO

The current trend toward urbanization and adoption of flexible and innovative mobility technologies will have complex and difficult-to-predict effects on urban transportation systems. Comprehensive methodological frameworks that account for the increasingly uncertain future state of the urban mobility landscape do not yet exist. Furthermore, few approaches have enabled the massive ingestion of urban data in planning tools capable of offering the flexibility of scenario-based design.

This article introduces Berkeley Integrated System for Transportation Optimization (BISTRO), a new open source transportation planning decision support system that uses an agent-based simulation and optimization approach to anticipate and develop adaptive plans for possible technological disruptions and growth scenarios. The new framework was evaluated in the context of a machine learning competition hosted within Uber Technologies, Inc., in which over 400 engineers and data scientists participated. For the purposes of this competition, a benchmark model, based on the city of Sioux Falls, South Dakota, was adapted to the BISTRO framework. An important finding of this study was that in spite of rigorous analysis and testing done prior to the competition, the two top-scoring teams discovered an unbounded region of the search space, rendering the solutions largely uninterpretable for the purposes of decision-support. On the other hand, a follow-on study aimed to fix the objective function. It served to demonstrate BISTRO’s utility as a human-in-the-loop cyberphysical system: one that uses scenario-based optimization algorithms as a feedback mechanism to assist urban planners with iteratively refining objective function and constraints specification on intervention strategies. The portfolio of transportation intervention strategy alternatives eventually chosen achieves high-level regional planning goals developed through participatory stakeholder engagement practices.

Follow-up outcomes of pediatric patients who underwent surgical resection for lipoblastomas or lipoblastomatosis: a single-institution experience with a systematic review and meta-analysis

PURPOSE

The objective of this study was to examine the long-term outcomes of pediatric patients who underwent surgical resection for lipoblastoma and lipoblastomatosis (LB/LBM).

METHODS

A single-center retrospective study of pediatric patients with LB/LBMs seen between 1991 and 2015 was conducted. A systematic review, including studies published prior to late August 2018, was performed. Using a random effect meta-analysis, pooled weighted proportions and unadjusted odds ratios (OR) with 95% confidence intervals (CI) were calculated.

RESULTS

The retrospective study included 16 patients, while the systematic review included 19 published studies consisting of 381 patients. Among 329 (82%) patients with follow-up information, the pooled recurrence rate was 16.8% (95% CI 10.9-23.5%; I² = 59%). The reported time to recurrence ranged from < 1 to 8 years. Recurrence risk was greater for incomplete (n = 34) than complete resection (n = 150): OR 11.4 (95% CI 3.0-43.6; I² = 43%). LBMs (n = 35) had a greater recurrence risk than LBs (n = 116): OR 5.5 (95% CI 1.9-15.9; I² = 0%). Recurrences were higher for studies with approximately ≥ 3 years of follow-up versus studies with < 3 years of follow-up.

CONCLUSION

Recurrences are more likely to occur with LBMs and/or incomplete resection. Follow-up beyond 3-5 years should be considered given that the recurrence risk appears to be greater in the long-term.

A contemporary review of myxoid adipocytic tumors

Myxoid adipocytic tumors encompass a broad heterogeneous group of benign and malignant adipocytic tumors, which are typically myxoid (e.g. myxoid liposarcoma, lipoblastoma and lipoblastoma-like tumor of the vulva) or may occasionally appear predominantly myxoid (e.g. pleomorphic liposarcoma, atypical lipomatous tumor, dedifferentiated liposarcoma, chondroid lipoma, spindle cell/pleomorphic lipoma, atypical spindle cell lipomatous tumor and atypical pleomorphic lipomatous tumor). There have been significant advances in recent years in classification and understanding the pathogenesis of adipocytic tumors, based on the correlation of histologic, immunohistochemical, and cytogenetic/molecular findings. Despite these advances, the morphologic diagnosis and accurate classification of a myxoid adipocytic tumor can be challenging due to major morphologic overlap between myxoid adipocytic and non-adipocytic tumors. This article will provide a review on the currently known morphological, immunohistochemical and molecular features of myxoid adipocytic tumors and their differential diagnosis.

Lipoblastoma: a clinicopathologic review of 23 cases from a major tertiary care center plus detailed review of literature

Objective

Lipoblastoma is a rare neoplasm that occurs mostly in infants and children. Although benign, it has a tendency for local recurrence.

Results

Clinical and pathological features of 23 cases of lipoblastoma described. Patients’ age ranged from 8 months to 18 years with mean and median age 4.1 and 2.5 years, respectively. Male:female ratio was 2.8:1. Most common sites were lower extremities (9 cases), followed by abdominal cavity and retroperitoneum (4 cases), and scrotum/groin (3 cases). Grossly, 22 tumors were well circumscribed and multi nodular. All cases showed lobules composed of adipocytes and lipoblasts with intervening fibrous septa and fine vascular network. Myxoid change, capsule formation and septation were seen in all cases. Zonation was seen in 2 cases. Follow-up was available in 14 out of 23 patients. Of these, 13 were alive and free of disease with no evidence of any recurrent lesion. One patient with a mediastinal infiltrating lipoblastoma experienced 4 recurrences. Lipoblastoma is a benign adipocytic neoplasm of infants and young children. Correlation of clinical and histological features helps in reaching a correct diagnosis. Owing to a high recurrence rate following incomplete resection, a complete resection is essential. Prognosis is excellent after complete resection.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3153-8) contains supplementary material, which is available to authorized users.

Lipoblastoma of the Labia: A Case Report

BACKGROUND

Vulvar masses are rare in prepubertal girls. Lipoblastomas are benign adipose tumors that arise from embryonic white fat and occur almost exclusively in infants and children.

CASE

An 18-month-old female infant presented with a 2-cm mobile mass in the left labia majora. Imaging and examination revealed normal prepubertal gynecologic structures and a 4.5 cm fatty mass in the left labia. Surgical excision revealed a 3.8 cm well circumscribed adipose tissue mass consistent with maturing lipoblastoma on microscopic examination. Cytogenetic analysis revealed 79,XXX [7]/46,XX[13], a near-triploid clone.

SUMMARY AND CONCLUSION

The differential diagnosis of vulvar masses in children should include lipoblastoma. Although preoperative imaging has limited ability to differentiate lipomatous tumors, magnetic resonance imaging is the modality of choice for evaluating tumor extension and for surgical planning. Treatment is complete surgical excision with close follow-up for at least 5 years because of the high recurrence rate.

Undifferentiated myxoid lipoblastoma with PLAG1-HAS2 fusion in an infant; morphologically mimicking primitive myxoid mesenchymal tumor of infancy (PMMTI)--diagnostic importance of cytogenetic and molecular testing and literature review

Lipoblastoma is a benign myxoid neoplasm arising in young children that typically demonstrates adipose differentiation. It is often morphologically indistinguishable from primitive myxoid mesenchymal tumor of infancy (PMMTI), which is characterized by a well-circumscribed myxoid mass with a proliferation of primitive mesenchymal cells with mild cytologic atypia. PMMTI occurs in the first year of life and is known to have locally aggressive behavior. No specific genetic rearrangements have been reported to date. In contrast, the presence of PLAG1 (Pleomorphic Adenoma Gene 1) rearrangement is diagnostic for lipoblastoma. We hereby demonstrate the combined application of multiple approaches to tackle the diagnostic challenges of a rapidly growing neck tumor in a 3-month-old female. An incisional tumor biopsy had features of an undifferentiated, myxoid mesenchymal neoplasm mimicking PMMTI. However, tumor cells showed diffuse nuclear expression by immunohistochemical (IHC) stain. Conventional cytogenetic and fluorescence in situ hybridization (FISH) analyses as well as next generation sequencing (NGS) demonstrated evidence of PLAG1 rearrangement, confirming the diagnosis of lipoblastoma. This experience warrants that undifferentiated myxoid lipoblastoma can mimic PMMTI, and the combination of cytogenetic and molecular approaches is essential to distinguish these two myxoid neoplasms. Literature on lipoblastomas with relevant molecular and cytogenetic findings is summarized. Our case is the first lipoblastoma diagnosed with a PLAG1 fusion defined by NGS technology.

Huge Mediastinal Lipoblastoma in a Nine Year-old Boy Successfully Removed Surgically

A nine year-old boy presented with symptoms of dyspnoea. The chest radiograph and computed tomography scan revealed a large mediastinal tumour. A decision to operate on the patient was made. A huge 2.45 kg mediastinal lipoblastoma was successfully removed from the boy's chest. At three years no evidence of recurrence was found.