Incidental dedifferentiated mediastinal liposarcoma on F-18-fluciclovine PET/CT

Thoracoscopic resection of primary mediastinal liposarcoma: a case report and literature review

BACKGROUND

Primary mediastinal liposarcomas (PLMs) are extremely rare. Patients typically present with symptoms caused by tumor size, as the mass can compress surrounding tissues and organs. Here, we report a case of a large primary mediastinal liposarcoma that was successfully resected thoracoscopically. By reviewing the available literature on mediastinal liposarcomas and sharing perioperative insights, we aim to provide guidance on the diagnosis and surgical management of large mediastinal liposarcomas.

CASE PRESENTATION

A 38-year-old male presented to our hospital with complaints of dysphagia after meals. Chest computed tomography (CT) revealed a large space-occupying lesion in the posterior upper mediastinum, and gastroscopy identified esophageal compression without evidence of new growth. The patient underwent thoracoscopic resection, resulting in significant improvement of his dysphagia postoperatively. He experienced no postoperative complications and was discharged one week following surgery.

CONCLUSION

The incidence of PLM is very low. Due to the proximity of vital structures such as the vena cava, esophagus, trachea, and subclavian artery, surgical resection presents elevated risks and complexity. While minimally invasive thoracoscopic techniques offer both safety and efficacy, careful preservation of surrounding organs is essential during the procedure.

Clinicopathological Features of Intrathoracic Liposarcoma-A Systematic Review with an Illustrative Case

BACKGROUND

Liposarcoma (LPS) is one of the most common soft-tissue sarcomas. However, intrathoracic LPS is rare, as only 1% of all LPS cases are found in the thorax.

METHODS

A systematic literature review through PubMed and Embase databases was performed. Only eligible case reports and case series reporting intrathoracic LPS in adult patients were included. Kaplan-Meier curves were calculated to evaluate the survival rate of included patients based on the histological subtype of LPS.

RESULTS

123 studies reporting 197 patients were included. We added a case of a 69-year-old female patient with recurrent giant intrathoracic LPS. The primary tumor measured 15.1cm × 22.9 cm × 21.9 cm and weighed 3100 g. Six months later, the patient was admitted to the hospital with another intrathoracic tumor measuring 9.5 cm × 9 cm× 1.4 cm. The immunohistochemical studies showed expression of murine double minute 2 (MDM2) antigen in both primary and recurrent tumor cells.

CONCLUSIONS

Dyspnea, chest pain, and cough were the most common symptoms reported in included studies. Overall, the 5-year survival rate was 62%. The highest survival was observed in well-differentiated LPS patients (80%) and the lowest in myxoid LPS (31%).

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.

Incidental Uptake of 18F-Fluciclovine by Type AB Thymoma

ABSTRACT

Biochemical recurrence of prostate cancer, detected by a rising PSA, may reflect intraprostatic or extraprostatic recurrence. 18F-Fluciclovine (Axumin), a synthetic amino acid substrate in tumor metabolism, has frequently been used for to localize recurrent prostate cancers. We present a 71-year-old man with biochemical recurrence of prostate cancer but no convincing imaging findings on 18F-fluciclovine PET/CT. Of note, however, was an incidental uptake within the anterior mediastinum, which was found on biopsy to be a type AB thymoma. With this, we stress that awareness of false-positive uptake patterns is crucial for accurate diagnosis of recurrent prostate cancer.

Synchronous Malignancies Identified by 18F-fluciclovine Positron Emission Tomography for Prostate Cancer: Case Series and Mini-Review

Positron emission tomography using the fluorine-18 (¹⁸F) fluciclovine radiotracer has been approved for use in recurrent prostate cancer and is a useful tool for clinical decision making. However, ¹⁸F-fluciclovine is not specific for prostate cancer tumor cells, and false-positive results have been reported. In the present study, we have reported our experience with synchronous malignancies identified using ¹⁸F-fluciclovine and reviewed other reported cases, with a special emphasis on highlighting the clinical decisions that led to the correct diagnosis.