Gastrointestinal stromal tumors (GISTs) arising within hepatic round ligament cysts are exceptionally rare, with limited literature available [1], hence making their definitive diagnosis challenging. Detective flow imaging (DFI) is a novel endoscopic ultrasound (EUS) modality for differentiating malignancies by evaluating irregular vessels [2]
[3]
[4]
[5]. We report a case in which DFI was crucial for differentiating benign and malignant lesions, leading to a diagnosis of GIST within a hepatic round ligament cyst.
A 44-year-old woman was referred for the evaluation of a 30-mm cystic lesion adjacent to the gallbladder. The distinction between the gallbladder and cystic lesions on transabdominal ultrasonography was uncertain. Contrast-enhanced computed tomography revealed a cystic lesion with an enhanced, partially thickened wall ([Fig. 1]). On magnetic resonance imaging, the gallbladder exhibited a low signal intensity, whereas the cystic lesion demonstrated a high signal intensity on diffusion-weighted image. This indicated that the cyst and gallbladder were discontinuous. EUS revealed a hypoechoic thickened wall in the cystic lesion ([Fig. 2]). DFI revealed an irregular vessel in the thickened wall within the cystic lesion, suggesting a malignant tumor ([Fig. 3]). Therefore, we decided to perform surgery ([Video 1]).
Fig. 1 Contrast-enhanced computed tomography reveals a cystic lesion with an enhanced, partially thickened wall (yellow arrowhead) adjacent to the gallbladder.
Fig. 2 Endoscopic ultrasound shows a hypoechoic thickened wall in the cystic lesion.
Fig. 3 Detective flow imaging shows an irregular vessel in the thickened wall, suggesting a malignant tumor.
A rare gastrointestinal stromal tumor within a hepatic round ligament cyst is diagnosed using detective flow imaging. This novel endoscopic ultrasound technique identifies irregular vessels and guides surgical decision-making.Video 1
During surgery, a cystic tumor was found in the round ligament of the liver. Histopathological examination revealed a cystic tumor with a thickened wall, characterized by sheet-like proliferation of epithelioid cells admixed with spindle-shaped cells, displaying a palisading pattern ([Fig. 4]). Immunohistochemical staining confirmed the diagnosis of GIST originating from a hepatic round ligament cyst ([Fig. 5]).
Fig. 4 Histopathological examination. a Cystic tumor with a thickened
wall (yellow arrowhead). b, c Hematoxylin-eosin: A thickened wall
is characterized by sheet-like proliferation of epithelioid cells admixed with
spindle-shaped cells, displaying a palisading pattern.
Fig. 5 Immunohistochemical staining of the tumor leads to the diagnosis of gastrointestinal stromal tumor. a Positive staining for CD117. b Negative staining for desmin. c Negative staining for S100.
To the best of our knowledge, this is the first reported case using DFI for the evaluation of a GIST arising within a hepatic round ligament cyst. The identification of an irregular vessel on DFI within the tumor can contribute to surgical decision-making in such rare cases.
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