P2943 - Primary Pancreatic Liposarcoma: An Unexpected Cause of a Pancreatic Mass

Tuesday, October 24, 2023

10:30 AM – 4:00 PM PT

Location: Exhibit Hall

Presenting Author(s)

Natalie Wilson, MD (she/her/hers)

University of Minnesota
Minneapolis, MN

Natalie Wilson, MD¹, Abdulfatah Issak, MD², Khalid Amin, MD², Todd M. Tuttle, MD², Guru Trikudanathan, MD², Shawn Mallery, MD²
¹University of Minnesota, Minneapolis, MN; ²University of Minnesota Medical Center, Minneapolis, MN

Introduction: Liposarcoma is the most common type of soft tissue sarcoma and typically occurs in the extremities or retroperitoneum. Primary liposarcoma of the pancreas is exceedingly rare, with only ten cases reported since 1979. Here, we present a case of a patient with an incidentally discovered pancreatic mass that was diagnosed as dedifferentiated pancreatic liposarcoma.

Case Description/Methods: A 52-year-old previously healthy male was incidentally found to have a pancreatic mass on a CT scan of the chest. CT abdomen and pelvis was then obtained and revealed a 10 cm lobulated mass (Figure 1A) in the pancreatic tail with extension into the splenic hilum and gastric fundus (Figure 1B).

An upper endoscopic ultrasound (EUS) was performed to obtain biopsies of the lesion. This revealed a large, atypical mass in the pancreatic tail with marked acoustic shadowing and areas of calcification (Figure 1C). The mass was in direct contact with the gastric wall and spleen and encased the splenic artery resulting in splenic vein occlusion and gastric varices. The uninvolved pancreatic parenchyma was hyperechoic suggestive of fatty infiltration but there was no evidence of chronic pancreatitis. Biopsies of the mass showed atypical spindle cells with immunohistochemical staining positive for CDK4 suggestive of liposarcoma, though excisional biopsy was recommended for definitive diagnosis.

After a multidisciplinary discussion, the patient underwent radical surgical resection of the mass and surrounding structures (distal pancreatectomy, partial gastrectomy, splenectomy, left hemicolectomy, and left adrenalectomy). The final pathology report confirmed dedifferentiated primary pancreatic liposarcoma with invasion into the spleen, gastric wall, and left colon wall (pT3) (Figure 1D). Tumor extended to the resection margins. Adjuvant chemotherapy with pembrolizumab was discussed though not yet started. A surveillance PET-CT scan was obtained three months after surgical resection and did not show recurrence or evidence of metastatic disease.

Discussion: Primary pancreatic liposarcoma is rare with only eleven documented case reports, including this study (Table 1). Surgical resection is the mainstay of treatment. Ongoing efforts should be made to report cases of pancreatic liposarcoma to increase awareness and knowledge of this rare diagnosis.

Figure: Figure 1. A) A 10 cm lobulated mass is seen in the tail of the pancreas (arrow). B) The mass can be seen extending into the hilum of the spleen and abuts the wall of the gastric fundus. Scattered internal calcifications are also seen. C) A large mass measuring 65 mm x 45 mm in diameter was seen in the pancreatic tail. It had scattered shadowing regions and poor through-transmission, precluding examination of deeper structures. D) Resection specimen showing dedifferentiated component of liposarcoma with significant nuclear pleomorphism characterized by nuclear size variability, irregular nuclear membranes and prominent nucleoli. (H&E stain, 20x magnification)

Study	Year	Age	Sex	Presentation	Location	Size (cm)	Subtype	Outcome
Elliott et al. Cancer 1980	1980	59	F	Abdominal distension	Body	16	Pleomorphic	No recurrence (6 years)
Dodo et al. World J Gastroenterol 2005	2005	76	M	Abdominal pain	Body/tail	9	Well-differentiated with an area of dedifferentiation	No recurrence (26 months)
Kuramoto et al. J Gastroenterol Hepatol. 2013	2013	24	M	Abdominal distension	Body	25	Myxoid	Recurrence (44 months)
Machado et al. Pancreatology. 2016	2016	42	M	Abdominal pain	Head	6.8	Dedifferentiated with high-grade components	No recurrence (5 years)
Matthews et al. Exp Mol Pathol. 2016	2016	65	F	Asymptomatic	Tail	4	Well-differentiated	N/A
Han et al. Cancer Biol Ther. 2017	2017	29	F	Abdominal distension	Tail	20	Dedifferentiated	No recurrence (12 months)
Cao et al. J Gastroenterol Hepatol. 2019	2019	72	F	Asymptomatic	Body/tail	10.3	Well-differentiated	N/A
Liu et al. World J Clin Cases. 2019	2019	28	F	Abdominal pain	Tail	28	Dedifferentiated with high-grade components	No recurrence (26 months)
Tanabe et al. Abdominal Radiology. 2022	2022	81	F	Asymptomatic	Tail	2.6	Dedifferentiated with well-differentiated component at the margin	N/A
Kim et al. Pancreas. 2014	2014	78	F	Asymptomatic	Body	7.3	Atypical lipomatous tumor/well-differentiated liposarcoma	No recurrence (2 months)
Present case	2023	52	M	Asymptomatic	Tail	10	Dedifferentiated	No recurrence (3 months)

Disclosures:

Natalie Wilson indicated no relevant financial relationships.

Abdulfatah Issak indicated no relevant financial relationships.

Khalid Amin indicated no relevant financial relationships.

Todd Tuttle indicated no relevant financial relationships.

Guru Trikudanathan: Boston Scientific Coporation – Consultant.

Shawn Mallery indicated no relevant financial relationships.

Natalie Wilson, MD¹, Abdulfatah Issak, MD², Khalid Amin, MD², Todd M. Tuttle, MD², Guru Trikudanathan, MD², Shawn Mallery, MD². P2943 - Primary Pancreatic Liposarcoma: An Unexpected Cause of a Pancreatic Mass, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.