A huge necrotic liver mass in a 45-year-old woman: delayed hepatic metastasis of a gastrointestinal stromal tumor

A 45-year-old woman was referred with a huge mass of the liver. She complained of a vague abdominal discomfort that had persisted for 1 month. She had no history of liver disease, and physical examination revealed mild abdominal distension. Pertinent laboratory test results were unremarkable. She had a history of small intestinal resection for a gastrointestinal stromal tumor (GIST) 11 years prior (Fig. 1A). Computed tomography (CT) showed a heterogeneous hypervascular tumor with central necrosis, occupying left hemiliver and right paramedian sector of the liver, measuring 20 × 13 cm (Fig. 1B). Positron emission tomography-CT using ¹⁸F-fluorodeoxyglucose showed intense hypermetabolic activity (maximum standardized uptake value 8.2) along the peripheral solid portion of the tumor with central photon defect area representing necrosis (Fig. 1C). A tumor biopsy revealed small round/spindle-shaped cells surrounded by fibrous tissue. Immunohistochemical stainings revealed vimentin reactivity, as well as CD117 reactivity. On c-kit sequencing, a deletion in exon 11 was identified. Based on the patient’s history, positive staining for CD117, and c-kit mutation results, the neoplasm was diagnosed as a metastatic GIST in the liver (Fig. 2). The pros and cons of using imatinib were discussed, and the patient was started at a dose of 400 mg/day and the dose had been tapered to 200 mg/day. One year follow-up CT showed the hepatic tumor slightly diminished in size, but stabilized at a size of 18 × 13 cm (Fig. 1D).

Figure 1.

(A) Eleven years ago, a small intestinal gastrointestinal stromal tumor, 11 × 6 cm size, of the patient was resected (arrowheads). (B) Abdominal computed tomography (CT) showing a heterogeneous hepatic tumor with central necrosis, measuring 20 × 13 cm. Note peripheral rim of the tumor displaying heterogeneous enhancement, indicating viable tumor portion (arrows). (C) Positron emission tomography-CT showing two contrasting ¹⁸F-fluorodeoxyglucose (FDG) uptake patterns of the tumor: the peripheral solid portion showing high metabolic rate (arrow, maximum standardized uptake value 8.2) and most of the inner portion showing FDG-void pattern, representing necrosis. (D) After 1 year of imatinib treatment, the tumor size reduced slightly to a size of 18 × 13 cm. Note the loss of peripheral enhancement of solid portion (arrows).

Figure 2.

(A) Tumor biopsy revealing small round/spindle-shaped tumor cells (H&E, ×100; inset, ×200). (B, C) Immunohistochemical stainings showing vimentin reactivity (B, ×200), as well as CD117 reactivity (C, ×200). (D) C-kit sequencing displaying a deletion in exon 11.

GISTs in the small bowel tend to be more aggressive than those in the stomach. The liver is most common metastatic site. Although hepatic metastasis of a GIST is not uncommon, delayed metastasis over 5 years later is extremely rare. A few cases of inoperable liver metastatic GISTs have been reported, most were treated by a multidisciplinary approach including imatinib administration and subsequent portal vein embolization leading to tumor shrinkage which enables curative resection.