Head and neck pleomorphic myxoid liposarcoma in a child with Li-Fraumeni syndrome

Atypical Spindle Cell/Pleomorphic Lipomatous Tumor: A Review and Update

Atypical spindle cell/pleomorphic lipomatous tumor (ASCPLT) is a rare and recently described adipocytic neoplasm that primarily occurs in the subcutis of the limbs and limb girdles, particularly of middle-aged adults. It has locally recurrent potential if incompletely excised but no risk for distant metastasis. ASCPLT is histologically similar to spindle cell/pleomorphic lipoma and atypical lipomatous tumor and shows a mixture of atypical spindle cells, adipocytes, lipoblasts, floret-like multinucleated giant cells, and/or pleomorphic cells. It has been recently recognized that ASCPLT can undergo sarcomatous transformation. However, the biological significance of morphological sarcomatous transformation in ASCPLT remains uncertain. Immunohistochemically, the tumor cells show variable expression of CD34, S-100 protein, and desmin. Loss of nuclear Rb expression is observed in the majority of cases. ASCPLT lacks MDM2 gene amplification but can show RB1 gene deletion in a significant subset of cases. Complete surgical excision is the treatment of choice. This review provides an overview of the current knowledge on the clinicoradiological features, pathogenesis, histopathology, and treatment of ASCPLT. In addition, we will discuss the differential diagnosis of this new entity.

Pleomorphic Liposarcoma Unraveled: Investigating Histopathological and Immunohistochemical Markers for Tailored Diagnosis and Therapeutic Innovations

Liposarcomas are some of the most challenging soft tissue tumors and are subclassified into multiple subtypes with special histologic and molecular features. The peculiarities of each histopathological subtype influence the clinical behavior, management, and treatment of these neoplasms. For instance, well-differentiated liposarcomas are common soft tissue malignancies and usually display a favorable outcome. On the other hand, pleomorphic liposarcoma is the rarest, yet the most aggressive subtype of liposarcoma. This histopathological diagnosis may be challenging due to the scarce available data and because pleomorphic liposarcomas can mimic other pleomorphic sarcomas or other neoplasms of dissimilar differentiation. Nevertheless, the correct diagnosis of pleomorphic liposarcoma is of utmost importance as such patients are prone to develop local recurrences and metastases. Treatment usually consists of surgical excision along with radiotherapy and follow-up of the patients. Therefore, this review aims to assess the complex clinical, histological, and immunohistochemical features of liposarcomas in order to establish how these characteristics influence the management and prognosis of the patients, emphasizing the particularities of pleomorphic liposarcoma.

Rare myxoid pleomorphic liposarcoma: a case report and literature review

We report a case of a middle-aged woman with a rapidly growing abdominal mass that was diagnosed as myxoid pleomorphic liposarcoma, a recently recognised, rare and aggressive subtype of liposarcoma. The tumour exhibits a combination of histological features from both myxoid liposarcoma and pleomorphic liposarcoma. Genetic analysis revealed mutations in TP53 and RB1, along with widespread loss of heterozygosity. However, no DDIT3 gene translocation or MDM2/CDK4 gene amplification was detected. These genetic characteristics can be used to distinguish this type of liposarcoma from others. Two unusual gene fusion/rearrangements, CREB5::TERT fusion and ETV1::LFNG rearrangement, were identified. The patient underwent complete removal of the tumour without the use of radiotherapy or chemotherapy. No recurrence was observed during the follow-up period of 18 months.

Myxoid pleomorphic liposarcoma in the teres minor muscle: A case report

RATIONALE

Myxoid pleomorphic liposarcoma (MPL) is a rare aggressive adipocytic tumor that mainly presents in children and adolescents. It is most frequently observed in the mediastinum and rarely in the head and neck, perineal region, or back. Herein, we report the first published case of MPL of the teres minor muscle.

PATIENT CONCERNS

A 24-years-old woman presented with a painless palpable mass in her right shoulder.

DIAGNOSES

Magnetic resonance imaging identified a 9.0 × 7.0 × 4.0 cm mass suspected to be a sarcoma in the teres minor muscle. Positron emission tomography/computed tomography revealed no evidence of distant metastasis. Histopathological examination revealed the mass to be an MPL, which was assigned a histologic grade of 3 according to the French Federation of Cancer Centers Sarcoma Group system. No tumor cells were observed along the resected margins.

INTERVENTIONS

Under general anesthesia, the right teres minor muscle containing the mass was excised en bloc and frozen biopsy confirmed that the tumor cells did not invade the surrounding tissues.

OUTCOMES

The patient underwent radiotherapy and was followed up for 6 months without complications.

LESSONS

Although MPL in the teres minor muscle is rare, it should be considered in the differential diagnosis in patients with a mass in the teres minor muscle due to its poor prognosis.

Primary intrathoracic liposarcomas: A clinicopathologic and molecular study of 43 cases in one of the largest medical centers of China

Introduction

Primary intrathoracic liposarcoma is extremely rare, and most published series lack genetic analyses. The aim of our study is to better understand the clinicopathologic and genetic features of these rare lesions.

Materials and methods

Forty-three primary intrathoracic liposarcomas were identified and most cases were analyzed by systematic genetic studies, including fluorescence in situ hybridization (FISH), whole-exome sequencing (WES), and Sanger sequencing.

Results

This series included 27 males and 16 females (ratios, 1.68:1) aged 24-73 years (median, 53 years). Tumors mainly occurred in the mediastinum (n=23, 53.5%), followed by pleural cavity (n=16, 37.2%) and lung (n=4, 9.3%). The study included 21 well-differentiated liposarcomas (WDLs), 19 dedifferentiated liposarcomas (DDLs), 2 myxoid pleomorphic liposarcomas (MPLs) and 1 pleomorphic liposarcoma (PL), without identification of myxoid liposarcoma. FISH analysis identified MDM2 amplification in 17 of 18 WDLs (94.4%) and all DDLs (16/16, 100.0%). The MDM2-nonamplified WDL was CDK4-nonamplified but FRS2-amplified. WES and Sanger sequencing found somatic TP53 mutation in the 2 MPLs. Follow-up information was available for 33 of 38 cases (86.8%). Thirteen patients (39.4%) showed no evidence of disease, 10 patients (30.3%) were alive with disease, and 8 patients (24.2%) died of disease. Fourteen cases developed recurrence and 1 with metastasis.

Conclusions

WDL/DDL was the overwhelming subtype in this location, followed by MPL and PL. Analysis of the FRS2 gene, in combination with MDM2 and other genes of 12q13-15, may more precisely characterize WDL/DDLs. MPL is the most fatal subtype of this site. Further studies are needed to explore the role of TP53 in the pathogenesis of MPL.

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.

Pediatric liposarcoma: A case series and literature review

Liposarcoma is arare soft tissue sarcoma in children. While prognosis, clinical behavior, and response to therapy among the various histologic subtypes are well described in adults, data in children are limited. Here, we describe our experience treating 14 children with liposarcoma at a large, academic pediatric center and review the available pediatric literature. This comprehensive report adds treatment, survival, and genomic data to pediatric liposarcoma literature.

Update on MR Imaging of Soft Tissue Tumors of Head and Neck

This article reviews soft tissue tumors of the head and neck following the 2020 revision of WHO Classification of Soft Tissue and Bone Tumours. Common soft tissue tumors in the head and neck and tumors are discussed, along with newly added entities to the classification system. Salient clinical and imaging features that may allow for improved diagnostic accuracy or to narrow the imaging differential diagnosis are covered. Advanced imaging techniques are discussed, with a focus on diffusion-weighted and dynamic contrast imaging and their potential to help characterize soft tissue tumors and aid in distinguishing malignant from benign tumors.

Myxoid pleomorphic liposarcoma-a clinicopathologic, immunohistochemical, molecular genetic and epigenetic study of 12 cases, suggesting a possible relationship with conventional pleomorphic liposarcoma

Myxoid pleomorphic liposarcoma is a recently defined subtype of liposarcoma, which preferentially involves the mediastinum of young patients and shows mixed histological features of conventional myxoid liposarcoma and pleomorphic liposarcoma. While myxoid pleomorphic liposarcoma is known to lack the EWSR1/FUS-DDIT3 fusions characteristic of the former, additional genetic data are limited. To further understand this tumor type, we extensively examined a series of myxoid pleomorphic liposarcomas by fluorescence in situ hybridization (FISH), shallow whole genome sequencing (sWGS) and genome-wide DNA methylation profiling. The 12 tumors occurred in 6 females and 6 males, ranging from 17 to 58 years of age (mean 33 years, median 35 years), and were located in the mediastinum (n = 5), back, neck, cheek and leg, including thigh. Histologically, all cases consisted of relatively, bland, abundantly myxoid areas with a prominent capillary vasculature, admixed with much more cellular and less myxoid foci containing markedly pleomorphic spindled cells, numerous pleomorphic lipoblasts and elevated mitotic activity. Using sWGS, myxoid pleomorphic liposarcomas were found to have complex chromosomal alterations, including recurrent large chromosomal gains involving chromosomes 1, 6-8, 18-21 and losses involving chromosomes 13, 16 and 17. Losses in chromosome 13, in particular loss in 13q14 (including RB1, RCTB2, DLEU1, and ITM2B genes), were observed in 4 out of 8 cases analyzed. Additional FISH analyses confirmed the presence of a monoallelic RB1 deletion in 8/12 cases. Moreover, nuclear Rb expression was deficient in all studied cases. None showed DDIT3 gene rearrangement or MDM2 gene amplification. Using genome-wide DNA methylation profiling, myxoid pleomorphic liposarcomas and conventional pleomorphic liposarcomas formed a common methylation cluster, which segregated from conventional myxoid liposarcomas. While the morphologic, genetic and epigenetic characteristics of myxoid pleomorphic liposarcoma suggest a link with conventional pleomorphic liposarcoma, its distinctive clinical features support continued separate classification for the time being.

A rare case of myxoid pleomorphic liposarcoma in an infant: A report

INTRODUCTION AND IMPORTANCE

MPL (myxoid pleomorphic liposarcoma) is an uncommon type of liposarcoma that affects mostly children and infants. Its aggressive behavior and tendency to recur warrant complete excision despite the challenges of troublesome locations.

CASE PRESENTATION

A 12-month-old infant presented with an insidious onset of noisy breathing and respiratory distress not relieved by supplemental oxygen via face mask. Examination revealed dullness and decreased air entry on the left chest. Computed Tomographic (CT) scan showed a large solid mass occupying the left hemithorax and displacing the mediastinum to the right. Intraoperatively, a large solid mass arising from the left chest wall and attached to the fifth rib was seen. Histopathology of the resected mass showed myxoid pleomorphic liposarcoma which is non-reactive for MDM2 immunostain.

CLINICAL DISCUSSION

Unlike other liposarcomas, myxoid pleomorphic liposarcoma occurs in children, commonly in the chest. CT scan is the preferred imaging modality. Treatment is by complete excision where possible. Molecular studies like Fluorescent in-situ Hybridization (FISH) and Immunohistochemistry (IHC) is used for confirmation. It has a high propensity to metastasize and recurrence is expected. Chemotherapy and irradiation following complete resection decrease the disease recurrence.

CONCLUSION

Soft tissue malignancy must be considered in the differential diagnosis of a large intrathoracic tumor in an infant. FISH and IHC are essential for confirmation.

Proton Radiotherapy to Reduce Late Complications in Childhood Head and Neck Cancers

In most childhood head and neck cancers, radiotherapy is an essential component of treatment; however, it can be associated with problematic long-term complications. Proton beam therapy is accepted as a preferred radiation modality in pediatric cancers to minimize the late radiation side effects. Given that childhood cancers are a rare and heterogeneous disease, the support for proton therapy comes from risk modeling and a limited number of cohort series. Here, we discuss the role of proton radiotherapy in pediatric head and neck cancers with a focus on reducing radiation toxicities. First, we compare the efficacy and expected toxicities in proton and photon radiotherapy for childhood cancers. Second, we review the benefit of proton radiotherapy in reducing acute and late radiation toxicities, including risks for secondary cancers, craniofacial development, vision, and cognition. Finally, we review the cost effectiveness for proton radiotherapy in pediatric head and neck cancers. This review highlights the benefits of particle radiotherapy for pediatric head and neck cancers to improve the quality of life in cancer survivors, to reduce radiation morbidities, and to maximize efficient health care use.

Pediatric Head and Neck Tumors Associated with Li-Fraumeni Syndrome

INTRODUCTION

Cancer predisposition syndromes are germline pathogenic variants in genes that greatly raise the risk of developing neoplastic diseases. One of the most well-known is Li-Fraumeni syndrome (LFS), which is due to pathogenic variants in the TP53 gene. Children with LFS have higher risks for multiple malignancies before adulthood, often with rare and aggressive subtypes.

OBJECTIVE

To examine head and neck manifestations of LFS in children treated at a tertiary children's hospital over a 20-year period.

METHODS

A retrospective review of LFS children with neoplastic disease presenting in traditional Otolaryngologic head and neck subsites from 2000 to 2019, with patient charts reviewed for relevant clinical, imaging, and operative data.

RESULTS

Of the 40 LFS patients initially identified, 27 neoplastic tumors were identified in 20 children within this cohort (20 primary, 7 second primary). Head and neck subsites aside from the brain or orbit were involved in 22% (6/27) of these tumors, representing 20% (4/20) of primary tumors and 29% (2/7) of second primary tumors. Both second primaries within the head and neck were within the radiation fields of the first primary tumor. The mean ages at primary and second primary diagnosis were 4.6 years (SD 3.5) and 12 years (SD 1.4), respectively. The male/female ratio was 1:6 among all patients with head and neck tumors. All 6 head and neck tumors were sarcomas. Rhabdomyosarcoma (N = 3, 50%) was the most common pathology, and the other 3 demonstrated rare tumor pathological subtypes (synovial cell sarcoma, pleomorphic myxoid liposarcoma, mandibular osteosarcoma). The neck was the most common subsite (75%) within this group for primary tumor presentation.

CONCLUSION

This study identifies a high potential for head and neck involvement in children with LFS, which has not been previously described in the literature. Otolaryngological care should be included in a multidisciplinary care team surveilling these patients.

Liposarcoma in children and young adults: a clinicopathologic and molecular study of 23 cases in one of the largest institutions of China

The incidence of pediatric liposarcoma is rare and most published cases lack systematic genetic analyses. We present clinicopathologic and genetic features of 23 liposarcomas aged <22 years. The study cohort comprised 10 males and 13 females (M:F=1:1.3) aged 11-21 years (median 17 years). The tumors predominantly occurred at the extremities (16/23; 69.6%), followed by the head/neck (2/23; 8.7%), chest (2/23; 8.7%), waist (2/23, 8.7%), and retroperitoneum (1/23; 4.3%). The tumor subtypes were sixteen myxoid liposarcoma (ML), one well-differentiated liposarcoma (WDL), two dedifferentiated liposarcoma (DDL), one pleomorphic liposarcoma (PL), and three myxoid pleomorphic liposarcoma (MPL) cases. Fluorescence in situ hybridization analysis identified MDM2/CDK4 amplification in all WDL/DDL cases (3/3; 100%) and DDIT3 rearrangement in all ML cases (13/13; 100%). Whole-exome sequencing indicated that one PL case and one MPL case exhibited RB1 loss. The two tested MPL cases had TP53 mutation and one of them harbored a TP53 germline mutation. Follow-up information was available for 20 patients (20/23; 87.0%) with a median follow-up duration of 42.5 months (range, 13-120 months). Three patients exhibited tumor progression (3/20;15.0%). Seventeen patients (17/20; 85.0%) survived with no evidence of disease. One MPL case (1/20; 5.0%) died of the disease. In conclusion, despite some overlaps, the occurrence, distribution of subtype, and prognosis of liposarcoma are overall different in children and adults. Most MLs and ALT/WDL/DDLs showed similar genetic aberrations with adult counterparts. Molecular features of MPL overlapped with those of conventional PL. The genetic characteristics including Tp53 status of MPL need further investigation.

The 2020 WHO Classification: What's New in Soft Tissue Tumor Pathology?

The fifth edition of the World Health Organization Classification of Tumors of Soft Tissue and Bone was published in early 2020. The revisions reflect a consensus among an international expert editorial board composed of soft tissue and bone pathologists, geneticists, a medical oncologist, surgeon, and radiologist. The changes in the soft tissue tumor chapter notably include diverse, recently described tumor types (eg, atypical spindle cell/pleomorphic lipomatous tumor, angiofibroma of soft tissue, and CIC-rearranged sarcoma), new clinically significant prognostic information for a variety of existing entities (eg, dedifferentiated liposarcoma and solitary fibrous tumor), and a plethora of novel genetic alterations, some of practical diagnostic relevance (eg, NAB2-STAT6 in solitary fibrous tumor, FOSB rearrangements in epithelioid hemangioma and pseudomyogenic hemangioendothelioma, and SUZ12 or EED mutations in malignant peripheral nerve sheath tumor, leading to loss of H3K27 trimethylation). In this review, we highlight the major changes to the soft tissue chapter in the 2020 World Health Organization Classification, as well as the new chapter on undifferentiated small round cell sarcomas, with a focus on updates in diagnostic categories, prognostication, and novel markers. Recent discoveries in molecular genetics are also discussed, particularly those of immediate utility in differential diagnosis, including protein correlates detectable using immunohistochemistry.

Cutaneous pleomorphic fibromas arising in patients with germline TP53 mutations

Pleomorphic fibromas are rare benign cutaneous neoplasms associated with deletion/loss of chromosomes 13q and 17p, where RB1 and TP53 are located, respectively. Herein, we report five cases of pleomorphic fibroma arising in patients with germline TP53 mutations, suggesting a potential link with Li-Fraumeni syndrome. All three patients were female and young (mean age 27) with a strong personal and/or family oncologic history and confirmed pathogenic germline TP53 mutations. In two patients, multiple pleomorphic fibromas were diagnosed. Clinically, the lesions arose at various cutaneous sites and were small (≤2 cm) and raised (4/5). Histopathologically, the tumors were paucicellular, composed of atypical spindled to stellate cells with hyperchromatic and variably pleomorphic nuclei. Mitotic activity was exceedingly low, although rare atypical mitotic figures were seen in one case. Immunohistochemically, the tumor cells were diffusely positive for p16 (3/3) and showed loss of Rb expression (5/5). All cases showed aberrant p53 expression (overexpression in 4, complete loss in 1). The tumors have followed a benign clinical course with no evidence of progression or recurrence. In conclusion, the development of multiple pleomorphic fibromas in a young patient may be a clue to an underlying genetic cancer syndrome involving TP53.

Recurrent Pleomorphic Myxoid Liposarcoma in a Patient With Li-Fraumeni Syndrome

Pleomorphic myxoid liposarcoma is an extremely rare, clinically aggressive subtype of liposarcoma that has been primarily reported in young patients. In this article, we report a case of a pleomorphic myxoid liposarcoma that presented as a second primary neoplasm in a 34-year-old man with history of primary mediastinal large B-cell lymphoma. During the clinical workup, the patient was diagnosed with a germline TP53 gene mutation and Li-Fraumeni syndrome. The tumor, a 2.9 × 2.3 × 2.0 cm well-demarcated and solid mass, was centered in the anterior chest wall soft tissue. Histologically, most of the tumor displayed abundantly myxoid stroma, low cellularity of mostly bland spindle cells, delicate branching capillaries, and lipoblasts; these areas transitioned to small areas whose features were reminiscent of pleomorphic liposarcoma. As assessed by fluorescence in situ hybridization, the tumor showed no DDIT3 ( CHOP) (12q13) rearrangements or MDM2 gene amplification. Clinically, the tumor progressed with multiple recurrences and metastasis to the humerus bone. To our knowledge, this is the first case of pleomorphic myxoid liposarcoma diagnosed in an adult with Li-Fraumeni syndrome.