Liposarcoma Involving Serous Fluid Cavities—A Case Series Illustrating Clinical Implications and the Diagnostic Role of Exfoliative Cytology

Abstract

Introduction: Cytological diagnosis of sarcomas requires detailed cytomorphological assessment and integration of immunocytochemistry and/or molecular testing. The role of exfoliative cytology, as compared to aspiration cytology, is less understood. This case series describes well-differentiated/dedifferentiated liposarcomas in effusions, with cytomorphological features, ancillary test results and clinical outcomes detailed. Methods: A computerized search of the department pathology archives was performed for sarcomatous effusions with histological diagnosis or clinical history of well-differentiated/dedifferentiated liposarcoma. Clinical progress, cytology slides, immunocytochemistry and molecular test results were reviewed. Results: Six patients were identified. In 5 patients with clinical follow up, 4 (80%) were deceased within 5 months of malignant effusion. One patient was alive with 12 years disease-free survival after radical resection with adjuvant radiotherapy. Three patients showed dedifferentiation on histology, and high-grade (dedifferentiated) tumor cells were present in effusion cytology of 2 patients. Two showed well-differentiated components only on biopsy, but high-grade (dedifferentiated) tumor cells were identified in cytology. The high-grade tumor cells displayed marked nuclear irregularity, enlargement, size variation, with macronucleoli and multinucleation. Well-differentiated lipomatous components were demonstrated in 4 patients (66.7%), comprising of multivacuolated lipoblasts and atypical lipocytes. CDK4 and MDM2 immunoreactivity in all 3 cases with cell blocks, and CDK4 and MDM2 amplification in one were successfully demonstrated. Conclusion: Lipomatous and dedifferentiated components can be sampled and cytomorphologically identified on effusion fluids of liposarcomas, with sufficient cellularity for immunocytochemistry and molecular testing. Although generally associated with poor prognosis, long disease-free survival with sarcomatous effusion is possible with radical surgery and adjuvant treatment.