Sailaja Pisipati, MBBS, MRCS, FRCS1, Chistie Elliott, MD2, Matthew Crapko, MD2, Ting Hui Hsieh, MD2
1University of Nevada School of Medicine, Reno, NV; 2Renown Regional Medical Center, Reno, NV
Introduction: Synovial sarcoma (SS) is a rare mesenchymal soft tissue sarcoma usually involving extremities close to large joints. SS of the GIT is uncommon; SS of the colon is extremely rare. Recognition and management of SS of the GIT can be very challenging. Here we report a rare case of asymptomatic SS of the rectosigmoid diagnosed as a surprising finding of surveillance colonoscopy.
Case Description/Methods: A 59-year-old asymptomatic lady with past medical history of diabetes mellitus, morbid obesity, colon polyps was referred for surveillance colonoscopy. Prior colonoscopy six years ago revealed two sigmoid colonic tubular adenomas. Examination was unremarkable except for a BMI of 44. Thorough examination of the musculoskeletal system did not reveal any abnormalities. Colonoscopy revealed a large, 5 cm pedunculated and superficially ulcerated round mass in the rectosigmoid colon, filling most of the lumen with the distal end of the lesion being ~15 cm above the anal verge. Biopsy demonstrated spindle cells with marked nuclear pleomorphism, high mitotic index rate, positive SS18 (SYT) gene rearrangement testing on FISH. Immunohistochemistry (IHC) was positive for TLE1, OSCAR, MCK, AE1/AE3, CK7 with Ki-67 of 70% and negative for desmin, CD117, DOG1, p63, CK5, CK6, S100, SMA. Findings were consistent with SS. Staging CT and PET-CT did not demonstrate distant spread. Robotic laparoscopic anterior resection with wide surgical resection margins and lymphadenectomy revealed T1N1 LN 2/20 stage 3 monophasic synovial sarcoma, with negative margins, 20% tumor necrosis and high mitotic rate. The patient was started on adjuvant chemotherapy with 5 cycles of Adriamycin 75 mg/m2 and Olaratumab on day 1 and day 8 of a 21-day cycle. A repeat PET-CT and a flexible sigmoidoscopy, six months later, did not reveal any tumor recurrence.
Discussion: Increasing number of cases of GIT SS are being reported. The majority of GI SS cases involved esophagus and stomach with pain, obstruction and bleeding being the common presenting symptoms; SS of the large intestine is extremely rare. Diagnosis is established by molecular genetics and IHC. Standardized treatment-guidelines are currently lacking. It is of paramount importance to i) consider SS on the list of differentials of colonic neoplasms, ii) report these unusual cases to better understand the pathophysiology, treatment options and success rates. This would facilitate more targeted and effective treatments for SS of the colon.
Citation: Sailaja Pisipati, MBBS, MRCS, FRCS; Chistie Elliott, MD; Matthew Crapko, MD; Ting Hui Hsieh, MD. P1965 - DON'T LET YOUR PAST DETERMINE YOUR DESTINY. Program No. P1965. ACG 2019 Annual Scientific Meeting Abstracts. San Antonio, Texas: American College of Gastroenterology.