Earlier detection of bone metastases from pleomorphic liposarcoma in a pediatric patient by FDG PET/CT than planar 99mTc MDP bone scan

Intense FDG Uptake in Well-Differentiated Inflammatory Liposarcoma of the Retroperitoneum

ABSTRACT

Inflammatory variant of well-differentiated liposarcoma is a rare subtype of liposarcoma, and its imaging features have been rarely reported. We describe FDG PET/CT findings in a case of well-differentiated inflammatory liposarcoma. The tumor showed no detectable fat and intense FDG uptake and caused diffuse FDG uptake of the bone marrow due to paraneoplastic leukemoid reaction. Microscopically, there were extensive inflammatory infiltrates in the tumor, which may contribute to the intense FDG uptake. This case indicates that although well-differentiated liposarcoma usually shows low-grade FDG uptake, inflammatory variant of well-differentiated liposarcoma can show intense FDG uptake mimicking high-grade liposarcoma.

Pleomorphic Liposarcoma of Femur: A Rare Soft Tissue Sarcoma Metastasized to the Bone—Case Report and Review of Literature

Background

Pleomorphic liposarcoma (PLPS) accounts for less than 5% of liposarcoma, and its metastasis to bone is rare. As a high-grade tumor, PLPS is reported to be more invasive with high local recurrence and distant metastasis. Here, we report a case of PLPS of the femur and undertake a review of the literature. Case Presentation. A 58-year-old man presented with a big mass at posterior aspect of his left thigh. The computed tomography of the chest for staging revealed two nodules at the left upper lung field. Wide resection of the soft tissue mass at the left thigh was performed by a general surgeon. Thoracotomy and wedge resection of the lung nodules was carried out by a cardiothoracic surgeon. Pathologic diagnosis suggested PLPS. Three years later, he was presented with sudden right hip pain after he slipped. The plain radiograph revealed an osteolytic lesion at the right proximal femur with minimally displaced pathological fracture. The MRI showed the presence of a tumor at the proximal part of the right femur and its soft tissue invasion. The patient underwent en bloc proximal femur wide resection followed by cemented long-stem bipolar hemiarthroplasty. The final histopathology report from definite surgery specimen revealed pleomorphic spindle, round, and polygonal cells arranged in sheets, short fascicles, and storiform arrays. There were no complications, adverse outcomes, or recurrence reported at six months after surgery. The patient could walk without gait aid and had good functional outcomes according to the TESS questionnaire.

Conclusion

PLPS is a highly aggressive tumor with a high distant metastatic rate. The definite diagnosis of PLPS is made on the basis of histopathology. Surgical treatment involving wide resection that aims to achieve a negative margin is the best option currently available, and we recommend treating bone metastasis from PLPS as the primary site of the tumor. The effect of chemotherapy and radiotherapy in preventing postoperative recurrence is still unclear and requires further studies.

FDG PET/CT in Dendritic Fibromyxolipoma of the Thigh

ABSTRACT

Dendritic fibromyxolipoma is a rare recently described benign soft tissue tumor, which may be misinterpreted histologically as myxoid liposarcoma or myxoid malignant fibrous histiocytoma. We describe FDG PET/CT and MRI findings of a dendritic fibromyxolipoma incidentally detected in a case with rectal adenocarcinoma. The dendritic fibromyxolipoma showed inhomogeneous FDG uptake with SUVmax of 4.0 mimicking malignancy.

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.

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.

18F-FDG PET/CT for identifying the potential causes and extent of secondary hemophagocytic lymphohistiocytosis

PURPOSE

We aimed to evaluate the value of 18F-FDG positron emission tomography/computed tomography (PET/CT) for identifying the possible causes of secondary hemophagocytic lymphohistiocytosis (HLH).

METHODS

Forty-five cases (17 female, 28 male; age, 17-79 years) with secondary HLH were included. The standard of reference for diagnosis in all patients was a combination of histology, clinical results (medical history, physical examination, and laboratory test results), and follow-up imaging for at least 12 months. All cases underwent 18F-FDG PET/CT to identify the possible trigger in HLH.

RESULTS

Of 45 secondary HLH cases 10 (22.2%) were associated with infection, seven (15.6%) with rheumatic disease, and 28 (62.2%) with lymphoma. PET/CT images of 22 secondary HLH cases (48.9%) showed true positive results. PET/CT images demonstrated obvious tracer uptake in five of 10 secondary HLH cases with infection, one of three cases with lupus, two of two cases with rheumatoid arthritis, one of two cases with adult-onset Still disease, and 13 of 28 cases with lymphoma.

CONCLUSION

PET/CT is helpful for identifying the possible trigger (infection or malignant disease) and extent of secondary HLH. However, PET/CT alone is not sufficient to make a correct differential diagnosis.

[Relapsed Pleomorphic Liposarcoma with Mediastinal Metastasis: A Case Report and Review of the Literature]

纵隔内转移性多形性脂肪肉瘤为纵隔内肿瘤的罕见病种，目前总体治疗效果欠佳。本文介绍腰大肌旁多形性脂肪肉瘤复发伴纵隔转移1例，探讨多形性脂肪肉瘤的临床特点和治疗策略。回顾性分析我院收治的1例转移性多形性脂肪肉瘤患者，基于影像学诊断与手术病理诊断，对患者进行针对性的多学科综合治疗。一名41岁女性患者，诊断腰大肌旁多形性脂肪肉瘤伴纵隔转移。经手术、靶向及化疗等多学科治疗，随访至今已65个月。对于多形性脂肪肉瘤治疗策略，应以外科完整切除为首选，术后辅助相关内科治疗，多学科综合治疗以延缓患者病情进展及复发。

Bone marrow metastases from alveolar rhabdomyosarcoma with impressive FDG PET/CT finding but less-revealing bone scintigraphy

An 18F-FDG PET/CT scan was performed in a 26-year-old man with a known alveolar rhabdomyosarcoma for staging. The PET/CT scan showed abnormally increased FDG activity involving almost all bones in the imaged regions. In contrast, 99mTc-MDP whole-body bone scan demonstrated only very limited bone metastases.

Detection of a metastatic lesion and tiny yolk sac tumors in two teenage patients by FDG-PET: report of two cases

We herein report the efficacy of FDG-PET for detecting yolk sac tumors in two teenage patients. One patient had a rare bone metastasis and the other had tiny recurrent lesions at the mediastinum. Both lesions were difficult to detect by conventional diagnostic modalities. In contrast, FDG-PET was very effective for detecting these lesions. Furthermore, the SUVmax of the lesion reflected the tumor activity, which was also suggested by the fluctuating values of serum alpha-fetoprotein (AFP), an established marker of yolk sac tumors. FDG-PET may be a useful procedure to detect tiny and metastatic, pediatric yolk sac tumors.