S2073 Dedifferentiated Liposarcoma Presenting as Dysphagia and Weight Loss: Common Symptoms of an Uncommon Diagnosis

Abstract

Introduction: Liposarcoma is a malignant soft-tissue tumor that frequently occurs in extremities and retroperitoneum but rarely affects the GI tract. We report a case of dedifferentiated liposarcoma manifesting as dysphagia and early satiety. Case Description/Methods: A 76 year old woman was referred for progressively worsening dysphagia for solids and liquids, early satiety and unintentional weight loss. She denied acid reflux symptoms, regurgitation, odynophagia or chest pain. She never smoked cigarettes nor consumed alcohol. Physical examination did not show cervical, supraclavicular or axillary lymphadenopathy. Esophagogastroduodenoscopy (EGD) showed an area of moderate to severe extrinsic compression in the lower esophagus from 31 cm to 38 cm from the incisors (Figure 1A). Contrast enhanced computed tomography (CT) scan of the chest revealed a 6 × 7 cm solid homogeneous mass in the lower middle/posterior mediastinum, laterally displacing the esophagus and the descending thoracic aorta, with anterior displacement of the heart (Figure 1B). No pathological lymphadenopathy was seen. Endoscopic ultrasound (EUS) showed a hypoechoic and homogenous mass with smooth borders. Fine needle aspiration (FNA) was performed (Figure 1C) for pathological diagnosis. Histopathology of the mass demonstrated a hypocellular infiltrate of pleomorphic cells in a loose collagenous matrix. There was no overt evidence of lipogenic differentiation, and mitotic activity was inconspicuous (Figure 1D). By immunohistochemistry, neoplastic cells were negative for epithelial, vascular, neural, and melanocytic markers. Fluorescent in-situ hybridization (FISH) detected MDM2 amplification in the formalin-fixed, paraffin-embedded tumor sample (Figure E), compatible with a diagnosis of dedifferentiated liposarcoma (DDL). Metastatic lesions were subsequently identified (AJCC stage IV). Discussion: Dedifferentiated liposarcoma (DDL) is one of the four major subtypes of liposarcomas. DDL typically has the appearance of undifferentiated pleomorphic or spindle cell sarcoma, and is associated with more aggressive clinical behavior and with a greater propensity for local recurrence and metastasis. The lack of specific symptoms can lead to delay in diagnosis. Systemic therapy with doxorubicin or other anthracyclines remains the treatment mainstay. The patient is currently receiving doxorubicin-based systemic therapy and under close clinical surveillance. This case highlights potential rare presentations of liposarcomas affecting the GI tract.Figure 1.: CT scan chest showing soft tissue mass in the anterior mediastinum.