Asymptomatic Duodenal Gastrointestinal Stromal Tumor Abscess

CASE REPORT

A 50-year-old man with a medical history of neurofibromatosis, ventral hernia, and hypertension was referred for evaluation of an incidental duodenal mass. An abdominal computed tomography scan for evaluation of abdominal discomfort secondary to bulging incisional ventral hernia revealed a 5.5 × 3.9 cm thick-walled gas and fluid-filled structure in the distal duodenum (Figure 1). Subsequent magnetic resonance imaging of the abdomen revealed a 5.5 × 4.3 cm enhancing centrally necrotic mass originating from the third and fourth portions of the duodenum (Figure 1). A push enteroscopy was performed using a pediatric colonoscope and revealed a submucosal mass at the third and fourth duodenal junction causing intraluminal narrowing. Spontaneous purulent discharge through a mucosal fistula was noted upon entry to the duodenal lumen (Figure 2). A ball-tip cannula was introduced through the fistula to sample the purulent discharge for cytology, Gram stain, and culture followed by saline irrigation. Biopsies from within the mass were obtained through the fistula opening using cold forceps. The patient was discharged empirically on ciprofloxacin and metronidazole, and Gram stain and culture later grew moderate Streptococcus anginosus and beta Streptococcus group F; cytology was negative for malignant cells. During this period, the patient remained clinically asymptomatic. Immunohistochemical stains from the submucosal mass biopsy showed neoplastic cells positive for CD34, CD117, and DOG1, consistent with mixed gastrointestinal stromal tumor (GIST) (Figure 3). The case was discussed in a multidisciplinary tumor board, and given the challenging surgical exposure and abutment of major vasculature, it was recommended to start neoadjuvant targeted therapy first to decrease the tumor burden before surgical resection. A follow-up positron emission tomography scan showed a hypermetabolic 5.5 × 4.3 cm lesion within the third and fourth portions of the duodenum compatible with the known GIST (Figure 4). The patient was started on sunitinib given that tumor specimens were negative for c-KIT and PDGFRA mutations.

Figure 1.

Axial (A) and coronal (B) sections of the abdominal and pelvic CT showing a 5.5 × 3.9 cm thick-walled gas-filled structure in the region of the third and fourth portions of the duodenum (white arrow). Axial (C) and coronal (D) sections of the abdominal MRI showing a 5.5 × 4.3 cm soft-tissue lesion originating from the third and fourth portions of the duodenum with central necrosis and gas (white arrow). CT, computed tomography; MRI, magnetic resonance imaging.

Figure 2.

(A) EGD showing a submucosal mass with a large amount of purulent discharge at the D3 and D4 levels (yellow arrows). (B) Mucosal fistula upon entry of the duodenal lumen (yellow arrow). EGD, esophagogastroduodenoscopy.

Figure 3.

(A) Hematoxylin and eosin stain showing mixed gastrointestinal stromal tumor of the duodenum (20× magnification). Immunohistochemical stains showing neoplastic cells positive for CD34 (B), CD117 (C), and DOG1 (D).

Figure 4.

PET scan showing hypermetabolic 5.5 × 4.3 cm lesion within the third and fourth portions of the duodenum (white arrow). PET, positron emission tomography.

GISTs are the most prevalent mesenchymal tumors in the gastrointestinal tract and can arise anywhere from the esophagus to the anus.¹ Cases with intratumoral abscess formation, as in our case, are rare, especially in the duodenum. The process of how intratumoral abscesses form involves enteric bacteria entering through a fistula, infecting the necrotic tissue within the tumor, and eventually developing into an abscess within the tumor.² That might be true in our case because there were no signs of infection in any other organ, except the duodenum. Our case highlights an unusual case of duodenal GIST complicated by abscess and fistula formation.

DISCLOSURES

Author contributions: MY Swied involved in the care of the patient, wrote the first draft of the manuscript, and wrote the final version after receiving input from the other authors. YA Turk was involved in the care of the patient and edited and reviewed the first draft of the manuscript. A. Swied performed diagnostic EGD on the patient, provided pictures and captions of EGD images, edited the second draft of manuscript, approved the final draft of the manuscript, and is the article guarantor. B. Whitehurst was involved in the care of the patient and reviewed and edited the final draft of the manuscript.

Financial disclosure: None to report.

Informed consent was obtained for this case report.