Chaudhary Ritica, Lisa Mona, Kumari Payal, Kumar Aman
Department of Pathology, IGIMS, Patna, Bihar, India.
Department of Surgery, UNC School of Medicine, Chapel Hill, NC, USA.
Clin Pathol. 2022 Jul 19;15:2632010X221112455. doi: 10.1177/2632010X221112455. eCollection 2022 Jan-Dec.
The retroperitoneum can host a wide spectrum of soft tissue lesions. These tumours pose a challenge to the pathologist as the morphology is not of much help and immunohistochemistry becomes a necessity.
Sixty years old male presented with 2 months history of abdominal lump, pain and dyspepsia. The MRI revealed a heterogeneous mass in the retroperitoneum involving right para spinal muscle, right iliac fossa and right perinephric region with destruction of right transverse process and erosion of adjacent L3 vertebra. Trucut biopsy of the mass was reported as fibroliposarcoma at an outside lab. Patient underwent a wide local excision. Grossly the tumour gave an impression of a liposarcoma but the microscopy showed areas of spindle cells, epitheloid cells, focal areas of ganglion like cells and large areas of myxoid change. IHC panel of S-100, SMA, caldesmon, myogenin, myoglobin and Alk-1 was negative. MDM2, CDK4 and p16 IHC came positive proving it to be a dedifferentiated liposarcoma.
We report a curious case of retroperitoneal soft tissue tumour with complex morphology and IHC features diagnosed as dedifferentiated liposarcoma based on MDM2, CDK and p16 positivity.
腹膜后可出现多种软组织病变。这些肿瘤给病理学家带来了挑战，因为形态学帮助不大，免疫组织化学成为必需手段。
一名60岁男性，有2个月腹部肿块、疼痛和消化不良病史。磁共振成像（MRI）显示腹膜后有一异质性肿块，累及右侧椎旁肌、右髂窝和右肾周区域，右侧横突破坏，相邻L3椎体侵蚀。在外部实验室，该肿块的粗针活检报告为纤维脂肪肉瘤。患者接受了广泛局部切除。大体上肿瘤给人一种脂肪肉瘤的印象，但显微镜检查显示有梭形细胞、上皮样细胞区域、局灶性神经节样细胞区域以及大片黏液样改变。S-100、平滑肌肌动蛋白（SMA）、钙调蛋白、生肌调节因子、肌红蛋白和碱性磷酸酶-1（Alk-1）的免疫组织化学检测结果均为阴性。MDM2、细胞周期蛋白依赖性激酶4（CDK4）和p16的免疫组织化学检测呈阳性，证实为去分化脂肪肉瘤。
我们报告了一例腹膜后软组织肿瘤的罕见病例，其形态学和免疫组织化学特征复杂，基于MDM2、CDK和p16阳性诊断为去分化脂肪肉瘤。
