A Case of Recurrent Symptomatic Malignant Pleural Effusion Due to Primary Pleural Myxoid Sarcoma

Abstract

INTRODUCTION: Primary pleural sarcomas are rare causes of pleural effusions and histopathological diagnosis is key in identifying, diagnosing and differentiating the various types. Histologically, four subtypes of liposarcomas exist: well differentiated, myxoid, lipoplastic, and pleomorphic. Pleural liposarcomas originate from primitive mesenchymal cells and are known to occur predominantly in older men with myxoid histology being the most common. CASE PRESENTATION:A 76 year old hispanic male former smoker with a history of laryngeal cancer post laryngectomy presented with progressive shortness of breath, orthopnea and bilateral lower extremity pitting edema over the course of five months. Chest x-ray showed a large right sided pleural effusion. A thoracentesis was performed with removal of 1800 ml exudative monocyte/macrophage predominant fluid, which provided him with symptomatic relief. All Infectious and rheumatologic workup was negative. Pathology of pleural fluid showed calretinin positive mesothelial cells. Within 2 weeks, he demonstrated a re-accumulation of his right sided pleural effusion. CT scan revealed stable right sided effusion with partially calcified pleural nodules. He underwent medical thoracoscopy with pleural biopsies and was noted to have 3 discrete tumors on the parietal pleura. Each of these lesions were biopsied and showed myxoid liposarcoma with low mitotic rate on pathology. Immunohistochemically, the tumor cells were focally positive for vimentin, and negative for S100, AE1/ AE3.DISCUSSION: Myxoid liposarcomas are most commonly extrapulmonary and pleural involvement is usually metastatic disease. Primary pleural malignancies tend to be diagnosed in the later stages. A thorough review of history, occupational exposure, radiographic, and immunohistochemical examination must be performed to rule out more common and likely diagnosis. In well-differentiated tumors, radiopaque foci caused by calcification and ossification may be seen. Pathologically determined grades of differentiation, site and size of tumor are the only known reliable sources to predict prognosis or outcomes. There is a lack of consensus and recommendations for treatment, which includes surgery (impractical if used as the only treatment modality due to high rates of local recurrence and irregular borders), adjuvant radiation and chemotherapy. Due to the rarity of this disease and limited information available, challenges in timely clinical diagnosis are encountered.CONCLUSIONS: Recognizing clinical presentations, radiographic, immunohistochemical, and pathological findings is paramount in understanding the prognosis of this possibly fatal condition. The atypicality of primary pleural myxoid sarcomas as a cause of recurrent pleural effusions reinforces the importance of obtaining a pathological diagnosis. Improved reporting and research may aid in supplementing additional crucial information and guide treatment.