A 25‐year‐old woman presented with 3 weeks of right upper quadrant abdominal pain. She described the pain as a “fullness” or “pulling” sensation. Over the past few days the pain had increased in intensity and became stabbing. She denied nausea, diarrhea, chest pain, dyspnea, or fever. The pain was not associated with food intake. She denied any recent travel, alcohol use, or a history of STDs. She did take oral contraceptive pills intermittently for 5 years. She was an obese woman in no distress. Vital signs were within normal limits. She did not have jaundice, icteric sclera, or pale conjunctiva. Her abdomen was soft, nondistended, and with normal bowel sounds. Right upper quadrant tenderness was present with mild palpation. There was no rebound or guarding. A large right upper quadrant mass was present that extended 20 cm along the midclavicular line. Laboratory analysis revealed a normal basic metabolic panel, hepatic panel, and white blood count. INR was 1.4; hemoglobin was 11 g/dL; platelets were 144 × 109/L. Hepatitis B and C serologies were negative. An abdominal CT scan revealed a heterogenous 18 × 18 × 18 cm right upper quadrant mass of unclear origin. A chest CT did not show metastases. Ultrasound‐guided biopsy showed a fibrovascular proliferation. During surgical resection, the mass was found to be retroperitoneal. Surgical pathology showed a low‐grade myxoid neoplasm consistent with soft‐tissue sarcoma.
In the workup of abdominal pain, it is not unusual that a hospitalist will discover an abdominal mass as the etiology. Although abdominal masses are typically related to liver, pancreatic, or bowel neoplasms, it is important to remember other forms of neoplasms present in the abdomen. Soft‐tissue sarcomas (STSs) are a rare type of neoplasm, comprising approximately 0.8% of all adult malignancies. The majority of STSs occur in the extremities; however, they can be found in other sites including the retroperitoneum. Typically, retroperitoneal STSs are not diagnosed until they are greater than 15 cm and locally advanced. Most patients have little to no symptoms until the STS is compressing or invading surrounding structures. Symptoms patients exhibit are abdominal pain, lower‐extremity edema, early satiety, and neuropathic lower‐extremity pain. CT scan of the abdomen/pelvis is the preferred imaging modality to assess for site of tumor origin. Chest CT is recommended, as the lungs are generally the first site of metastasis. Biopsy is only indicated if the diagnosis is uncertain or if the mass is unresectable. If surgery is planned, preoperative tissue diagnosis is not necessary. Complete surgical resection with clear borders is the only potential cure for retroperitoneal STS.
While bringing attention to a rare abdominal neoplasm, this case highlights the importance of formulating a broad differential diagnosis when evaluating abdominal pain.
To cite this abstract:Pedram K. Myxing Up the Differential, an Unusual Case of an Abdominal Mass. Abstract published at Hospital Medicine 2013, May 16-19, National Harbor, Md. Abstract 349. Journal of Hospital Medicine. 2013; 8 (suppl 2). https://www.shmabstracts.com/abstract/myxing-up-the-differential-an-unusual-case-of-an-abdominal-mass/. Accessed April 10, 2020.