A 63‐year‐old African American woman presented with 2 weeks of progressively worsening right lower quadrant abdominal pain. She noted early satiety, constipation, and an unintentional 10‐pound weight loss. On exam, her abdomen was distended and tender to palpation in the right lower quadrant with voluntary guarding. A large mass was palpated in the right lower quadrant. The mass was also palpated anteriorly on rectal exam. Computed tomography scan revealed a large, 14 × 11 × 22 cm heterogeneously enhancing mass in the pelvis with areas of coarse calcification and necrosis. Mass effect was seen on the rectum, bladder, and inferior vena cava; bilateral obstructive hydronephrosis was present. Needle biopsy showed a spindle cell neoplasm. Subsequent immunohisto‐chemical studies revealed the tumor to be positive for CD117, CD34, DOG01, vimentin, and cytokeratin, supporting a diagnosis of a gastrointestinal stromal tumor (GIST). Neoadjuvant imatinib (Gleevac™) therapy was begun with plans for serial scans to assess maximal response prior to surgical resection.
The prompt recognition and diagnosis of a GIST is essential for hospitalists because the medical treatment for GISTs may lead to improvement in surgical outcomes and prolongation of recurrence‐free survival. This case emphasized the importance of accurate diagnosis of a mass, as it immediately changed management. The initial imaging in our patient was concerning for a retroperitoneal mass, and evaluation proceeded quickly to determine the origin, with a plan for a possible surgical resection. The broad differential diagnosis of a retroperitoneal mass, including soft‐tissue sarcomas, lymphoma, primary germ cell tumor, and rarely GIST, makes it essential for a clinician to obtain a biopsy for tissue diagnosis. Because most tumors in the retroperitoneal space are associated with nonspecific symptoms such as abdominal pain, patients do not usually present until the tumor is locally advanced and large. Surgical resection is the only curative treatment, but unfortunately, the late presentation of these tumors may lead to increased morbidity and mortality. In our patient, the diagnosis of GIST changed the treatment plan and postponed surgery. Because the majority of GISTs have a mutation in the KIT proto‐oncogene, these tumors respond well to molecular‐targeted therapy in the form of receptor tyrosine kinase inhibitors, such as imatinib or sunitinib. This response has led to treatment of previously unresectable or metastatic GISTs and may lead to improved surgical outcomes in patients receiving neoadjuvant therapy.
Timely recognition, diagnosis, and treatment of a retroperitoneal mass by hospitalists is essential, as most present late and can involve surrounding structures, leading to significant morbidity and mortality. GISTs often have favorable response to established medical therapies, which may lead to improved surgical outcomes.
W. Tan ‐ none; J. Christenbury ‐ none; R. Riedel ‐ none; S. Chudgar ‐ none
To cite this abstract:Tan W, Christenbury J, Riedel R, Chudgar S. Understanding the Gist of a Retroperitoneal Mass. Abstract published at Hospital Medicine 2011, May 10-13, Dallas, Texas. Abstract 412. Journal of Hospital Medicine. 2011; 6 (suppl 2). https://www.shmabstracts.com/abstract/understanding-the-gist-of-a-retroperitoneal-mass/. Accessed May 24, 2019.