Pleomorphic liposarcoma arising on the cheek: a case report and review of the literature

<p class="abstract">Pleomorphic liposarcoma, which is the rarest of the four liposarcoma types according to the World Health Organization (WHO) classification of soft tissue tumors, is associated with a high rate of recurrence and poor prognosis. In the present report, we present the case of a 69-year-old male patient with pleomorphic liposarcoma arising in the right cheek. The mass was initially considered as benign such as schwannoma due to the absence of facial nerve palsy. However, the mass grew rapidly, requiring surgical removal with facial nerve preservation. Pathological and molecular examination led to the definitive diagnosis of pleomorphic liposarcoma. The postoperative adjuvant radiotherapy was added, and there were no signs of recurrence at four-year follow-up.</p>

Larotrectinib in a Patient With Advanced Pleomorphic Liposarcoma of the Uterus

Pleomorphic liposarcoma of the uterus (PLU) is an extremely rare disease with poor prognosis. Limited treatment options exist for these patients, and disease recurrence usually occurs rapidly within months of initial diagnosis. Few case reports of metastatic PLU are available in the literature. We describe a 70-year-old woman who presented with a large uterus and ovarian mass on imaging and negative serum tumor markers and endometrial biopsy. Staging revealed localized disease. Surgical resection revealed PLU on pathology. Immunohistochemistry was negative for smooth muscle actin (SMA), S100, and MDM2, and positive for CD10 and cyclin-D1. She was treated with adjuvant therapy and experienced disease recurrence in the liver at 15 months from surgery. Genetic testing of the metastasis showed IQGAP-NTRK3 gene fusion. She was given entrectinib but continued to show progression in the liver. Right partial hepatectomy was performed, showing positivity for CD10, BCL-1, MDM2, and SMA on tumor staining. Treatment was switched to pazopanib with disease progression in the neck. She was treated with larotrectinib last, showing no disease progression and adequate tolerance of therapy after 18 months of this treatment. This is the first case in the literature of metastatic PLU with NRTK3 fusion treated with sequential first-generation NRTK inhibitors. More case reports are needed to identify commonalities and therapeutic options. Genetic testing in all PLU cases is needed for targeted therapy approaches.

Human leukocyte antigen I is significantly downregulated in patients with myxoid liposarcomas

The characteristics of the tumor immune microenvironment remains unclear in liposarcomas, and here we aimed to determine the prognostic impact of the tumor immune microenvironment across separate liposarcomas subtypes. A total of 70 liposarcoma patients with three subtypes: myxoid liposarcoma (n = 45), dedifferentiated liposarcoma (n = 17), and pleomorphic liposarcoma (n = 8) were enrolled. The presence of tumor infiltrating lymphocytes (CD4+ , CD8+ , FOXP3+ lymphocytes) and CD163+ macrophages and expression of HLA class I and PD-L1 were assessed by immunohistochemistry in the diagnostic samples; overall survival and progression-free survival were estimated from outcome data. For infiltrating lymphocytes and macrophages, dedifferentiated liposarcoma and pleomorphic liposarcoma patients had a significantly higher number than myxoid liposarcoma patients. While myxoid liposarcoma patients with a high number of macrophages were associated with worse overall and progression-free survival, dedifferentiated liposarcoma patients with high macrophage numbers showed a trend toward favorable prognosis. Expression of HLA class I was negative in 35 of 45 (77.8%) myxoid liposarcoma tumors, whereas all dedifferentiated liposarcoma and pleomorphic liposarcoma tumors expressed HLA class I. The subset of myxoid liposarcoma patients with high HLA class I expression had significantly poor overall and progression-free survival, while dedifferentiated liposarcoma patients with high HLA class I expression tended to have favorable outcomes. Only four of 17 (23.5%) dedifferentiated liposarcomas, two of eight (25%) pleomorphic liposarcomas, and no myxoid liposarcoma tumors expressed PD-L1. Our results demonstrate the unique immune microenvironment of myxoid liposarcomas compared to other subtypes of liposarcomas, suggesting that the approach for immunotherapy in liposarcomas should be based on subtype.