Differentiation between gastrointestinal schwannomas and gastrointestinal stromal tumors by computed tomography

Abstract

Abstract. The aim of the present study was to identify computed tomography (CT) features to assist in differentiating gastrointestinal schwannomas from gastrointestinal stromal tumors (GISTs). CT images of gastrointestinal schwannomas (n=15) and GISTs (n=50) were analyzed. The absolute CT values of tumor/aorta during plain scan/arterial phase/venous phase were recorded as tumor plain scan (Tp)/aorta plain scan (Ap), tumor arterial phase (Ta)/aorta arterial phase (Aa) and tumor venous phase (Tv)/aorta venous phase (Av), respectively, and normalized CT values of the three phases were calculated as Sp=Tp/Ap, Sa=Ta/Aa and Sv=Tv/Av, respectively. The difference in tumor CT value between arterial and venous phases was calculated and recorded as Tv-a. CT data including tumor size, contour, margin, growth pattern, presence of calcification, cystic change, hemorrhage, ulceration, perilesional lymph nodes (PLNs), local invasion to surrounding structures, metastasis, ascites, vasculatures, enhancement pattern/degree, Tp/Ta/Tv and Sp/Sa/Sv were evaluated for each patient. Receiver operating characteristic (ROC) curve analysis was used to assess the ability of the CT data to differentiate gastrointestinal schwannomas from GISTs. Compared with GISTs, gastrointestinal schwannomas more frequently demonstrated round contouring, relatively smaller tumor size, a homogeneous enhancement pattern, with the presence of PLNs and a higher level of vasculature (P<0.05), whilst the presence of cystic changes were more common in GISTs compared with gastrointestinal schwannomas (P<0.05). The Sa, Ta and Tv-a of gastrointestinal schwannomas were less compared with those of GISTs (P<0.05). The difference in margin, growth pattern, intra-tumoral calcifications and hemorrhage were insignificant (P>0.05). ROC analysis indicated that tumor size, cystic change, the presence of PLNs, tumor enhancement pattern and Sa demonstrated improved diagnostic potential compared with others [area under the curve (AUC) >0.7], amongst which cystic change demonstrated the best diagnostic ability (AUC=0.82). Size exhibited the highest sensitivity, 90%, and cystic change, Sa exhibited the best specificity, 87%. Quantitative analysis indicated that certain features aided the differentiation between gastrointestinal schwannomas and GISTs using CT imaging. IntroductionSchwannoma are benign tumors arising from Schwann cells in the sheaths of peripheral nerves. Schwannoma are homogeneous tumors and may occur in any tissue of the body. The head and neck region is the most prevalent location for schwannoma to occur; they are rarely observed in the gastrointestinal tract (1). Conventional schwannoma usually arise from peripheral skin nerves and connective tissue, whereas gastrointestinal schwannoma tumors are derived from Schwann cells of the Auerbach's plexus within the gastrointestinal tract wall (1-3) and were first reported by Daimaru et al in 1988 (1)

Clinical Characteristics and Surgical Management of Gastrointestinal Schwannomas

“…GS more likely demonstrates smaller tumor size, round shape, and homogeneous enhancement pattern in CT than GIST. At the same time, perilesional lymph nodes and high vasculature are more frequently seen in GS, while cystic change is more common in GIST [33]. Unlike in other gastrointestinal tumors, perilesional lymph nodes are not a sign of malignancy in GS [34].…”

Gastrointestinal schwannomas: a rare but important differential diagnosis of mesenchymal tumors of gastrointestinal tract

“…A preoperative diagnosis of GI schwannomas is generally difficult and challenging, if not impossible, since the tumor have no specific clinical symptoms and no diagnostic modality can show any pathognomonic features unique to this tumor [ 22 ]. On CT examination, these tumors mostly represent as exophytic masses displaying homogeneous enhancement in most cases whereas cystic change, cavity formation, necrosis or calcification are uncommon [ 7 , 16 , 24 ]. Our CT findings were comparable to previous reports in terms of enhancement patterns and growth patterns.…”

Computed tomographic characteristics of gastric schwannoma

“…The growth pattern of the tumor was classified as exophytic, endoluminal, or mixed growth. 16 The enhancement pattern was classified as either homogeneous or heterogeneous. Contrast enhancement (in Hounsfield units [HU]) was calculated from the difference in tumor CT values between the portal phase and plain scan, and was graded as mild (<10 HU), moderate (10–40 HU), and marked (>40 HU).…”