P2311 - Role of Endoscopic Ultrasound Fine Needle Biopsy Confirmation in a Large Retroperitoneal Mass

Yash P. Ashara, MBBS¹, Ruchir Paladiya, MBBS², Allyson Pagan, MD³, Ami Bhalodia, MBBS⁴, Bhavtosh Dedania, MD^5
1Mayo Clinic, Rochester, MN; ²UConn Health, Hartford, CT; ³HCA West Florida Brandon, Brandon, FL; ⁴Duke University, Durham, NC; ⁵HCA Florida Brandon Hospital, Brandon, FL

Introduction: Sarcomas are a rare group of malignant tumors derived from mesenchymal tissues, constituting less than 1 % of all adult malignancies. Retroperitoneal sarcoma is uncommon, comprising about 13% of all sarcomas. Here, we present a unique case of retroperitoneal well-differentiated liposarcoma diagnosed with endoscopic ultrasound (EUS) guided fine needle biopsy (FNB) and how it helped change the management in our patient.

Case Description/Methods: A 77-year-old Thai male with a previous smoking history complained of loss of appetite, progressive 20 lb. weight loss over 6 months and left upper quadrant abdominal discomfort. CT of the abdomen revealed a large 19.5 x 13.2 cm mass in the LUQ with no clear distinction for origin. Labs showed Hb of 8.6 g/dL with MCV 74 fL suggestive of iron deficiency anemia with normal CEA, CA 19-9 & AFP. CTA of the abdomen showed extensive arterial supply to the mass, but no definitive site origin could be ascertained. The patient was seen by a surgical oncologist, who recommended undergoing biopsy confirmation before any resection, as the differentials were quite broad. EUS showed a large lobulated hyperechoic solid mass (Figure A-B) with no invasion or origin from pancreas, liver, or stomach wall. A large 23 X 22 mm lymph node was also observed (Figure C). EUS-FNB with a 22-gauge core needle confirmed the diagnosis of well-differentiated liposarcoma with MDM2 amplification. Based on pathology findings, the patient directly underwent surgical resection without any need for preoperative chemotherapy or radiation.

Discussion: Given the uncommon occurrence of liposarcoma and the complexities associated with its diagnosis and management, it is imperative to adopt a multidisciplinary approach for evaluation. A biopsy confirmation of the histological diagnosis is necessary as other differentials like a large GIST would warrant a neoadjuvant chemotherapy or a high-grade myxoid/round cell liposarcoma would need chemo-radiation therapy whereas our patient went straight to surgery. Traditional methods of image-guided percutaneous needle biopsy or incisional biopsy of retroperitoneal masses may pose complications during subsequent surgical resection. In this context, EUS-guided FNB emerges as a crucial tool, offering minimal invasiveness and aiding in confirming the diagnosis of retroperitoneal masses. This approach facilitates the identification of appropriate treatment strategies based on pathology findings.



Disclosures:


Yash P. Ashara, MBBS¹, Ruchir Paladiya, MBBS², Allyson Pagan, MD³, Ami Bhalodia, MBBS⁴, Bhavtosh Dedania, MD⁵. P2311 - Role of Endoscopic Ultrasound Fine Needle Biopsy Confirmation in a Large Retroperitoneal Mass, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.