Giant Primary Retroperitoneal Dedifferentiated Liposarcoma

Excerpt

A 65-year-old woman presented with vomiting, pain, and significant abdominal distension. Physical examination demonstrated a painful large palpable mass involving the whole abdomen (Fig. 1a). Laboratory investigations showed low hemoglobin (7.8 g/dl) and protein (5.2 g/dl) level. Computed tomography (CT) scan showed a 34 × 32 × 35-cm heterogeneous fatty mass with septations and solid nodules within the lesion showing high contrast enhancement, filling the entire abdominal cavity, with right kidney encasement (Fig. 2a). Abdominal visceral displacement was observed (Fig. 2b). Preoperative biopsy showed lipomatous tumor. At laparotomy, the well-circumscribed, lobulated mass, weighing about 30 kg underwent complete excision, including a right nephrectomy (Fig. 1b), and the greatest difficulty was to obtain vascular control of major vessels. Microscopically, the tumor was characterized by the presence of pleomorphic lipoblasts with large, hyperchromatic nuclei scalloped by cytoplasmatic vacuoles (Fig. 3a). Immunohistochemical analysis was positive for CDK4 and MDM2 (Fig. 3b). Diagnosis was dedifferentiated liposarcoma grade III. Oozing hemorrhage without overt source requiring relaparotomy occurred in postoperative day 5. The patient was discharged 10 days later. She was lost at follow-up after 12 months without evidence of recurrence.

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