This report describes our experience with two cases that were ultimately diagnosed as retroperitoneal liposarcoma using endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Case 1 is that of a 54-year-old woman with chief complaints of nausea and abdominal distention. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a large (15 cm diameter) tumor, which was significantly compressing the stomach and apparently occupied the entire left abdominal cavity. Although advanced primary gastrointestinal stromal tumor (GIST) or retroperitoneal tumor was inferred as the differential diagnosis, a definitive diagnosis was difficult using imaging alone. After EUS-FNA was done, the tumor was diagnosed histopathologically as high-grade liposarcoma. Case 2 is that of a 73-year-old man. Abdominal ultrasonography and CT showed a 6 cm diameter tumor within the pelvic cavity. The tumor had high MRI signal-intensity on both T1 and T2 images. Endorectal EUS showed a hyperechoic mass. The images suggested lipoma or liposarcoma containing lipoma-like components. Myxoid liposarcoma was revealed by subsequent EUS-FNA. Performing EUS-FNA was clinically useful for determining the subsequent therapeutic strategy in these cases where a tumor of unknown origin existed in the retroperitoneum.
Endoscopic ultrasonography (EUS) is an important modality in the evaluati of luminal gastrointestinal diseases as well as diseases of the pancreas, gallbladder, and biliary ductal system. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has been developed as a diagnostic tool using EUS [
Although liposarcoma is a malignant soft-tissue tumor that frequently occurs in extremities and retroperitoneum [
A 54-year-old woman who suffered from nausea and abdominal distention had consulted with her family doctor. She had no previous history of a related disease or these symptoms. Esophago-gastro-duodenoscopy (EGD) showed a subepithelial mass on the upper gastric corpus; an abdominal CT showed a huge tumor as a low-density mass occupying most of the left side of the abdominal cavity (Figure
(a) Abdominal CT showing a huge tumor as a low-density mass occupying much of the left side of the abdominal cavity. (b) Sagittal T2-weighted MR image showing a mosaic-patterned high-intensity mass, with an enclosed low-intensity septum.
A mass was identified as hypoechoic with some partial hyperechoic lesions suggesting hemorrhage within the tumor on EUS. EUS-FNA was performed using the transgastric approach.
Histopathological examination revealed a few signet-ring-cell-like lipoblasts and several pleomorphic cells manifested in a myxoid background (Giemsa stain, ×60).
A 73-year-old man who showed a retroperitoneal mass on abdominal ultrasonography for health screening visited our hospital for further examination. Results of CT showed a 6 cm diameter low-density tumor within the pelvis (Figure
(a) CT showing a 6 cm diameter low-density tumor within the pelvis. (b) Axial T2-weighted MR image showing a very-high-intensity mass with a low-intensity septum (arrows).
EUS showed that the internal echo was homogeneously hyperechoic and the hypoechoic septum (arrows) was also apparent. Subsequently EUS-FNA was performed using a transrectal approach.
Histopathological examination revealed lipoblasts of various sizes and spindle cells with slightly atypical nucleus manifested against a myxoid background (Giemsa stain, ×60).
Liposarcoma is a kind of sarcoma that preferentially develops in the extremities (40%), retroperitoneal space (19%), and groin (12%), accounting for 9.8–16% of all sarcomas [
Histopathologic classification of liposarcomas was proposed by WHO classification [
Histopathologic classification of liposarcoma.
Grade | Classification | Prognosis (survival rates at 5 years) |
---|---|---|
Low-grade | Well-differentiated [ | 85% |
Myxoid type [ | 77% | |
High-grade | Round-cell type [ | 21% |
Pleomorphic type [ | 18% | |
Dedifferentiated type [ | 30% |
As for treatment of liposarcomas, surgical therapy is the first option in resectable cases. Retroperitoneal liposarcoma has few clinical symptoms. Therefore, it often infiltrates into the surrounding organs. Consequently, the local recurrence rate is as high as 60% at five years. Decreasing the risk of recurrence requires en bloc excision including as much surrounding tissue as possible to prevent remnant tumor tissue [
EUS guided FNA has been applied for cytopathological diagnosis of a variety of lesions within and outside the gastrointestinal tract. Although there is a case of pancreatic metastasis of liposarcoma diagnosed by EUS-FNA [