Unusual presentation of metastatic gastrointestinal stromal tumour

Abstract

A 59-year-old Chinese male had a known history of a 15 × 14 × 9 cm, mitotic index 3 per 10 hpfs jejunal gastrointestinal stromal tumour (GIST) surgically resected 13 years ago. He did not receive adjuvant imatinib after surgical resection. Surveillance imaging up to 10 years post-surgery revealed no evidence of recurrence or metastatic disease, and he was discharged from follow up. On routine health screening, he was noted to have hepatomegaly and deranged liver function tests: alkaline phosphatase 165 U/ L, alanine transaminase 405 U/L and aspartate transaminase 509 U/ L. The white blood cell count was 4.69 × 10 9 cells/L. Computed tomography (CT) scan revealed a large 16.2 × 13.5 cm complex cystic mass in the right hepatic lobe (Fig. 1). The cyst had a thickened wall with septations and had low-density content with dependent debris. There was mass effect noted on the biliary confluence, with mild dilatation of both right and left bile ducts. There were no other masses suggestive of recurrent GIST. An F-18 fluorodeoxyglucose PET-CT scan that was performed demonstrated no significant increased metabolic activity in the mass. As the investigations were indeterminate, the patient was offered the option of upfront surgical resection of the liver cyst versus a biopsy. The patient elected to have a biopsy, which was subsequently performed. Percutaneous aspiration and biopsy of the hepatic lesion was performed, which demonstrated haemorrhagic cyst fluid (Fig. 2). The smears show mostly blood with scattered degenerated cyst macrophages and occasional clusters of hepatocytes. No other epithelial cell component was identified, and no significant viable inflammatory infiltrates were seen. There were no malignant cells seen. Core biopsies of the cyst walls only demonstrated necrotic debris. Cyst fluid cultures revealed no bacterial or fungal growth. After discussion, the patient elected to undergo an extended right hemihepatectomy for the complex cystic mass. © 2017 Royal Australasian College of Surgeons ANZ J Surg 89 (2019) E204-E205