S2551 Gone to Guts: A Case of Osteosarcoma With Metastasis to Upper and Lower Gastrointestinal Tract Presenting as Recurring Bleeding

Abstract

Introduction: Osteosarcomas are the most common bone tumors in children and adolescents. They are notoriously known to metastasize to lungs, however metastasis to gastrointestinal tract is extremely rare and only reported in sparse case reports.1–5 To our knowledge, we present one of the first cases of osteosarcoma that metastasized to the upper and lower GI tract presenting as recurrent bleeding. Case Description/Methods: A 43-year-old man with medical history of metastatic osteosarcoma to the lungs and brain, initially diagnosed at the age of 20 years in the femur, presented to the hospital after a syncopal episode. Patient had been having intermittent melena for a month prior to presentation. Oncological treatments included ifosfamide, doxorubicin, carboplatin, and etoposide. On presentation, his vitals were significant for HR 102, and BP 85/40 mmHg. Physical exam revealed a non-tender abdomen and rectal exam was positive for melena. His labs are outlined in Table. Chest X-ray revealed metastatic lung nodules. Enteroscopy showed no bleeding up to proximal jejunum. A 2cm ulcerated nodule was noted in the jejunum which was not actively bleeding (Figure A). Colonoscopy with deep cannulation of terminal ileum (40 cm) revealed old blood throughout. Again, similar 2-3 cm ulcerated transverse and hepatic colon nodules were noted which were biopsied (Figure B). Pathology revealed spindle-shaped cells with marked nuclear atypia with poor immunoreactions indicating poorly differentiated sarcoma. CT angiography of the abdomen showed evidence of metastatic nodules in the small and large bowel. Patient’s family opted for comfort measures given his poor surgical candidacy and overall prognosis. Discussion: In line with other sparsely reported cases, our case presented with luminal bleeding from multiple ulcerated nodules.1,3,4 To our understanding, this was one of the first cases that had simultaneous involvement of both upper and lower GI tract. With the growing incidence of osteosarcoma, it would aid gastroenterologists in understanding clinical presentation and endoscopic appearance to timely recognize this condition and thereby impact outcomes.Figure 1.: A) EGD image showing a 2cm ulcerated jejunal nodule. B,C) Colonoscopy images showing 2-3cm ulcerated nodules in the hepatic and transverse colon. Table 1. - Laboratory values with reference range on presentation Lab parameter Value Units Reference range WBC count 17.70 X 1000 cells/uL 4-10 RBC count 2.28 Million/uL 3.5-5.5 Hemoglobin 5.3 g/dL 12-16 Hematocrit 18.3 % 35-45 MCV 80.3 fL 84-96 Platelet count 257 X 1000/uL 150-400 RDW 19.40 % 12-15 Sodium 135 mmol/L 132-143 Potassium 4.2 mmol/L 3.5-5.1 Chloride 102 mmol/L 98-107 Carbon dioxide 26 mmol/L 21-31 BUN 33 mg/dL 7-25 Creatinine 0.8 mg/dL 0.7-1.3 BUN/Cr ratio 34 6-22 AST 22 IU/L 13-39 ALT 10 IU/L 7-52 ALP 49 IU/L 34-104 Albumin 3.0 g/dL 3.7-4.9 Total Bilirubin 1.1 mg/dL 0.2-1.2 INR 1.32 0.90-1.10 Lactic acid 3.07 mmol/L 0.5-1.99