case report

Imaging Features of Pancreatic Dedifferentiated Liposarcoma: A Rare Case Report

Peijia Xu1, Yifeng Huang2, Junwen Huang3, Jiayi Wu1, Chenjia Lu3, Ting Xue1, Xinkui Xue4, Liya Wang1,4*

1Department of Radiology, Affiliated Longhua People's Hospital, the Third School of Clinical Medicine, Southern Medical University, Shenzhen, Guangdong 518109, China

2Department of Surgery, the People's Hospital of Longhua, Shenzhen, Guangdong 518109, China

3Department of Pathology, the People's Hospital of Longhua, Shenzhen, Guangdong 518109, China

4Medical Research Center, the People's Hospital of Longhua, Shenzhen, Guangdong 518109, China

*Corresponding author: Liya Wang, Department of Radiology, Affiliated Longhua People's Hospital, the Third School of Clinical Medicine, Southern Medical University, Shenzhen, Guangdong 518109, China

Received Date: 03 February 2023

Accepted Date: 06 February 2023

Published Date: 09 February 2023

Citation: Xu P, Huang Y, Huang J, Wu J, Lu C, et al (2023) Imaging Features of Pancreatic Dedifferentiated Liposarcoma: A Rare Case Report. Ann Case Report. 8: 1158. DOI:https://doi.org/10.29011/2574-7754.101158

Abstract

Dedifferentiated lip sarcoma (DDLPS) is a rare subtype of lip sarcoma with poor prognosis. This current case report described a primary pancreatic DDLPS in a 51-year-old Chinese female suffering from intermittent pain in her middle and upper abdomen for one year after three years of radical gastrectomy. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) were undertaken to identify and evaluate the tumour details. The patient underwent resection of the pancreatic tumour. The spindle cell proliferation was found by pathologic HE staining. Further immunohistochemistry and genetic testing were recommended and detected the positive for minute 2 (MDM2), cyclin-dependent kinase 4 (CDK4) and signal transducer and activator of transcription 6 (STAT6) in this specimen. The case report also reviewed the literature in terms of the radiologic and pathological characteristics of DDLPS for the aim of improving the preoperative diagnosis and accurate location of tumour.

Keywords: Case Report; Computed Tomography (CT); Dedifferentiated Lip sarcoma; Magnetic Resonance Imaging (MRI); Pancreas

Introduction

Dedifferentiated lip sarcoma (DDLPS) is a rare neoplasm that exhibits various morphologies. It is a distinct subtype of lip sarcoma that defines a morphological transition from well-differentiated lip sarcoma (WDL) or atypical lipomatous tumour to high-grade sarcoma [1]. The tumour is characterized of mouse double minute 2 (MDM2) amplification by fluorescence in situ hybridization (FISH). Surgical resection is the most effective treatment for DDLPS, while radiotherapy and chemotherapy have ineffective curative effects. The earlier the diagnosis, the better the surgical effect. More effective and non-invasive diagnosis of DDLPS is needed to improve the preoperative diagnosis and accuracy location. With the development of medical imaging technology, especially the application of clinic Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). Both of them play key roles to diagnose DDLPS with the typical characterization, which displayed a soft tissue mass with varied composition and closely related to the proportion and distribution of different differentiation components [2]. However, the imaging features related to pancreatic lip sarcoma were few reported previously [3]. The primary DDLPS is an extremely rare in the pancreas [3-5]. Herein, we report an unusual case of DDLPS arising from the tail of pancreas with relevant imaging features of both CT and MRI, as well as pathological evidences in order to improve the diagnosis and location of DDLPS before surgery.

Case Presentation

A 51-year-old Chinese female presented to the department of Hepatobiliary Surgery, the People's Hospital of Longhua, Shenzhen, Guangdong province, China in October 2020 due to her intermittent pain in the middle and upper abdomen for one year. The patient underwent radical gastrectomy for gastric cancer three years earlier. Before the hospitalization, she had undergone abdominal CT and MRI scans in the same hospital above. An abdominal unenhanced CT identified a round soft tissue mass measuring 5.7 X 6.7 X 6.8 cm3 in the tail of pancreas. The CT value of mass was 51 Hu in unenhanced CT images [Figure 1A], but the CT values were increased to 77 Hu, 86 Hu, and 109 Hu, respectively post-contrast at arterial [Figure 1B], venous [Figure 1C] and delayed periods [Figure 1D]. The mass was closely related to the tail of pancreas and the pancreatic tail was compressed, but the boundary of adjacent surface was not clear partly showing as yellow arrow in Figure 1A-1D. The representation of mass was relatively homogeneous, but detected a minimum CT value at -80 Hu in low-attenuation areas, which might indicate very less fat components in coronal position [Figure 1E]. The adjacent splenic artery and vein were compressed and displaced in the volume rendering (VR) imaging [Figure 1F]. The shadow of surgical clipping for radical gastrectomy was observed as long strip high density in the gastric body from multi-planar reformatting (MPR) in sagittal position [Figure 1G]. No abnormal enhanced lesions were found in CT images. A tumour of the tail of pancreas, likely neuroendocrine tumour, was considered by CT impression.

 

Figure 1: An abdominal CT showing a round soft tissue mass in the tail of pancreas. The representation of mass was relatively homogeneous in non-enhanced image (A), but becoming to in the arterial, venous and delayed periods in (B-D). A minimum CT value at -80 Hu in low-attenuation areas was detected in coronal position (E). The adjacent splenic artery and vein were displaced in the volume rendering (VR) imaging (F). The shadow of surgical clipping for radical gastrectomy was observed in multi-planar reformatting (MPR) in sagittal position (G). The yellow arrows indicate the unclear boundary of adjacent surface partly between the tumour and tail of pancreas.

Thereafter, MRI was implemented and demonstrated a mass in the body and tail of pancreas. Its size was approximately 5.8 X 6.7 X 6.8 cm3 with heterogeneous appearance. The most areas of the mass were hypo intensity in T2 weighted imaging (T2WI) and T2WI with fat suppression sequence, rather than hyper intensity in diffusion weighted imaging (DWI). The boundary of lesion was relatively clear as shown in Figure 2A-2C. MR enhanced images revealed the tumour in T1 weighted imaging (T1WI) from homogeneous iso-intensity in pre-contrast [Figure 2D] to heterogeneous enhancement in the arteriovenous period [Figure 2E-F] and stronger enhancement in the delay period [Figure G]. The tail of pancreas was compressed and shifted forward, while, the arteriovenous of spleen was moved backward [Figure 2H]. However, it was found that the adjacent surface between tumour and the pancreatic pancreas was not clear slightly showing as yellow arrow in Figure 2D-G. It might indicate that the tumour was originally from the tail of pancreas. There was no obvious dilation of the pancreatic duct observed in magnetic resonance cholangiopancreatography (MRCP) showing in the Figure 2I. The characteristic of metastatic lymph nodes or lesion was not found in all MR images. In addition, no abnormal enhancement was observed in the residual stomach. Therefore, MRI impressed the tumour as a ligamentous fibroma originating in the tail of pancreas.

 

Figure 2: MR images presented the tumour in the pancreatic tail (arrow). The tumour showed the heterogeneous hypo intensity in the T2WI (A) and fat suppression T2WI (B), rather than hyper intensity in DWI (C). T1WI revealed the tumour with relative iso-intensity in precontrast (D) and increased enhancements at arteria (E), portal (F), and balance (G) period in the axial position. More details, the adjacent surface between tumour and the pancreatic pancreas was not clear slightly (arrow in D-G). The tumour in coronal position was showed in the T2-weighted with fat suppression sequence (H). The normal MRCP was presented in (I). The yellow arrows showed the location of the tumour.

In retrospective observation, a few high signal area mixed within the tumour, which showed a slight hyper-intensity in multi-Dixon T1WI [Figure 3A], but the signal intensity was suppressed to hypo-intensity in fat suppression of multi-Dixon sequence as showing in Figure 3B.