Imaging in gynecological disease (19): clinical and ultrasound features of extragastrointestinal stromal tumors (eGIST)

Abstract

Objective To describe the clinical and sonographic characteristics of extragastrointestinal stromal tumors (eGISTs). Methods This was a retrospective multicenter study. The data of patients with a histological diagnosis of eGIST who had undergone preoperative ultrasound examination were retrieved from the databases of nine large European gynecologic oncology centers. One investigator from each center reviewed stored images and ultrasound reports, and described the lesions using the terminology of the International Ovarian Tumor Analysis and Morphological Uterus Sonographic Assessment groups, following a predefined ultrasound evaluation form. Clinical, surgical and pathological information was also recorded. Results Thirty‐five women with an eGIST were identified; in 17 cases, the findings were incidental, and 18 cases were symptomatic. Median age was 57 years (range, 21–85 years). Tumor marker CA 125 was available in 23 (65.7%) patients, with a median level of 23 U/mL (range, 7–403 U/mL). The vast majority of eGISTs were intraperitoneal lesions (n = 32 (91.4%)); the remaining lesions were retroperitoneal (n = 2 (5.7%)) or preperitoneal (n = 1 (2.9%)). The most common site of the tumor was the abdomen (n = 23 (65.7%)), and less frequently the pelvis (n = 12 (34.3%)). eGISTs were typically large (median largest diameter, 79 mm) solid (n = 31 (88.6%)) tumors, and were less frequently multilocular‐solid tumors (n = 4 (11.4%)). The echogenicity of solid tumors was uniform in 8/31 (25.8%) cases, which were all hypoechogenic. Twenty‐three solid eGISTs were non‐uniform, either with mixed echogenicity (9/23 (39.1%)) or with cystic areas (14/23 (60.9%)). The tumor shape was mainly lobular (n = 19 (54.3%)) or irregular (n = 10 (28.6%)). Tumors were typically richly vascularized (color score of 3 or 4, n = 31 (88.6%)) with no shadowing (n = 31 (88.6%)). Based on pattern recognition, eGISTs were usually correctly classified as a malignant lesion in the ultrasound reports (n = 32 (91.4%)), and the specific diagnosis of eGIST was the most frequent differential diagnosis (n = 16 (45.7%)), followed by primary ovarian cancer (n = 5 (14.3%)), lymphoma (n = 2 (5.7%)) and pedunculated uterine fibroid (n = 2 (5.7%)). Conclusions On ultrasound, eGISTs were usually solid, non‐uniform pelvic or abdominal lobular tumors of mixed echogenicity, with or without cystic areas, with rich vascularization and no shadowing. The presence of a tumor with these features, without connection to the bowel wall, and not originating from the uterus or adnexa, is highly suspicious for eGIST. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Malignant epithelioid neoplasm of the ileum with ACTB-GLI1 fusion mimicking an adnexal mass

“…Visible peritoneal implants, omental thickenings, and hepatic, splenic and lymph node secondary involvement were not observed. The examiner classified this tumor as probably malignant and the suspect diagnosis according to the literature was Extra Gastrointestinal Stromal tumor (eGIST) [ 10 ]. A tumor staging CT scan was carried out in our department that was negative for infiltrated lymph nodes and distant metastasis.…”

Imaging in gynecological disease (26): clinical and ultrasound characteristics of benign retroperitoneal pelvic peripheral‐nerve‐sheath tumors

“…They are moderately vascularized by intralesional vessels and circumscribed by a hyperechogenic rim of epineurium. Their sonographic features may be similar to those of a malignant retroperitoneal tumor arising from soft tissue (such as eGIST 39 or leiomyosarcoma 42 ) or lymph node 15,40 . However, observation on ultrasound of their close relationship with underlying nerves might suggest a PNST, prompting an ultrasound‐guided core needle biopsy which can then confirm the diagnosis preoperatively, facilitating appropriate patient referral to a specialized center capable of providing multidisciplinary care in such cases.…”

“…In our series, the most common false-positive diagnosis on ultrasound was eGIST (differential diagnosis of leiomyoma in Case 1 and primary consideration in Case 2), due to their very similar sonomorphologic appearance. eGISTs usually present as slow-growing, solitary, non-uniform, solid, well-vascularized and wellcircumscribed tumors, without acoustic shadowing 39 . Based on the results of our multicenter study on eGISTs, published in 2020 39 , these are more highly vascularized compared with benign PNSTs (eGISTs vs benign PNSTs: color score 3, 23.5% vs 100.0%; color score 4, 67.6% vs 0.0.%).…”

“…In addition to deep endometriosis on the left rectovaginal ligament, a solid tumor 45 mm in largest diameter was detected incidentally in the left paracervix on transvaginal ultrasound imaging (Figure 2, Videoclip S1). The presumed diagnosis was a benign intraligamentary myoma, but a malignant tumor (such as an eGIST 39 or metastatic lymph node 15,40 ) could not be excluded. Since the mass was located subperitoneally with no risk of intraperitoneal tumor-cell contamination, a transvaginal ultrasound-guided core needle biopsy was carried out during the examination, which revealed a tumor with neurogenic differentiation, likely a schwannoma.…”

Extra-Gynecological Pelvic Pathology: A Challenge in the Differential Diagnosis of the Female Pelvis

“…Ultrasound manifests as solid, non-uniform, pelvic, or abdominal tumors of mixed echogenicity with or without cystic areas, with abundant vascularization, and without acoustic shadowing. The presence of a tumor with these characteristics without connection to the intestinal wall and that does not originate in the uterus or adnexa is highly suspicious of being an eGIST ( Figure 10 and Figure 11 ) [ 16 , 17 ].…”