Search Results (266)

Background/Objectives: Succinate dehydrogenase (SDH)-deficient gastrointestinal stromal tumors (GISTs) are a rare subgroup of GISTs and respond poorly to conventional systemic therapies. This study describes long-term outcomes after yttrium-90 (Y-90) selective internal radiation therapy (SIRT) for progression of unresectable SDH-deficient GIST hepatic metastases. Methods: We performed a retrospective review of consecutive patients treated with SIRT at three tertiary referral centers in Europe and the United States. Data collection included demographics, tumor profiling, prior therapies, Y-90 dosimetry approach, imaging response, adverse events, and long-term outcomes. Results: Twelve patients (66.7% female) with a median age of 27 years (range, 17–57 years) were included. One patient had a complete response (8.3%) and seven had partial responses (58.3%) by modified Response Evaluation Criteria in Solid Tumors. Four patients (33.3%) had tumor shrinkage that did not meet partial response criteria. The objective response rate was 66.7%, with a disease control rate of 100%. One grade 3 or higher adverse event was observed (cholecystitis requiring cholecystectomy). At a median follow-up of 32 months (range, 3–77 months), two patients experienced disease progression. Median overall survival was not reached, with one death during follow-up. Conclusions: SIRT appears safe and effective for patients with progressive, unresectable SDH-deficient GIST hepatic metastases, with durable responses and limited serious toxicity. These findings suggest that SDH-deficient GIST may be more sensitive to radiation than previously appreciated and that SIRT may be a useful liver-directed approach for patients with limited systemic options. Full article

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract and are usually driven by activating mutations in KIT or PDGFRA. Although these alterations define the core molecular biology of GISTs and guide targeted therapy, they do not fully explain the variability observed in tumor behavior, recurrence risk, or response to tyrosine kinase inhibitors. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), have been increasingly studied as regulators of gene expression in GISTs. Recent evidence suggests that these molecules may influence KIT-centered signaling, autophagy, apoptosis, invasion, angiogenesis, and drug resistance. However, the strength of evidence differs considerably across individual ncRNAs, ranging from bioinformatic associations to functional validation in cell lines and in vivo models. This review summarizes current knowledge on ncRNA-mediated regulation in GIST biology, with emphasis on tumor progression, therapeutic resistance, and possible clinical relevance. Rather than treating ncRNAs as isolated biomarkers, they function as part of broader regulatory networks that interact with oncogenic signaling and epigenetic mechanisms. Although several ncRNAs appear promising as prognostic or predictive candidates, further validation in independent clinical cohorts is required before their integration into routine risk stratification or treatment decision-making. Full article

Background/Objectives: Oligometastatic GIST, defined in this study as five or fewer metastatic lesions confined to a single organ, represents a distinct subset with a lower metastatic burden than widely metastatic disease and may have different prognostic and therapeutic considerations. Methods: We reviewed biopsy-proven oligometastatic GIST diagnosed between August 1998 and June 2025 from a prospectively maintained institutional database, collecting genomic, metastatic, treatment, ethnicity, and survival data. Overall survival (OS), calculated from diagnosis of oligometastatic disease, was estimated by Kaplan–Meier analysis and compared using the log-rank test. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression. Results: Of 525 subjects with GIST in our database, 96 (18.3%) had oligometastatic GIST (median age: 54 years; median OS from diagnosis of oligometastatic disease: 9.77 years). Most tested tumors were KIT-positive (91.6%), predominantly harboring KIT exon 11 alterations (69.5%). The most common metastatic sites were the liver (n = 44) and peritoneum (n = 37). Overall, 58 patients underwent surgery, including 55 cytoreductive procedures and 3 emergent operations for bleeding or obstruction. Among the cytoreductive procedures, indications included multifocal disease after tyrosine kinase inhibitor (TKI) response (n = 21), unifocal disease after TKI response (n = 18), unifocal progression on TKI (n = 13), and equivocal or undocumented TKI response (n = 3). Overall survival did not differ by liver versus peritoneal metastases (HR: 1.27; 95% CI, 0.59–2.70; p = 0.540) or Hispanic versus non-Hispanic ethnicity (HR: 0.81; 95% CI, 0.34–1.90; p = 0.624). Cytoreductive surgery combined with systemic therapy was associated with longer overall survival than systemic therapy alone (10.8 vs. 7.4 years; HR: 0.44; 95% CI, 0.22–0.89; p = 0.019). Conclusions: In this retrospective cohort, cytoreductive surgery combined with systemic therapy was associated with longer overall survival than systemic therapy alone. Full article

Immune checkpoint inhibitors (ICIs) have significantly changed the treatment landscape of several gastrointestinal (GI) malignancies, particularly microsatellite instability-high (MSI-H) and mismatch repair-deficient (dMMR) tumors. However, most GI cancers remain resistant to current PD-1/PD-L1-based immunotherapy because of complex and highly suppressive tumor microenvironments characterized by immune stromal exclusion, myeloid-driven immune suppression, defective antigen presentation, and adaptive immune resistance mechanisms. Emerging evidence suggests that alternative inhibitory pathways, including lymphocyte activation gene-3 (LAG-3), T-cell immunoreceptor with immunoglobulin and ITIM domain (TIGIT), T-cell immunoglobulin and mucin-domain containing-3 (TIM-3), and V-domain Ig suppressor of T-cell activation (VISTA), contribute substantially to persistent T-cell dysfunction and resistance to checkpoint blockade. This review summarizes the immune landscape of GI malignancies and discusses the biological mechanisms underlying resistance to current ICIs. We highlight the evolving role of next-generation immune checkpoints, ongoing clinical development of novel inhibitors, and emerging combination strategies involving chemotherapy, anti-angiogenic therapy, radiation, bispecific antibodies, and tumor microenvironment modulation. In addition, we discuss current limitations in biomarker development and the growing role of circulating tumor DNA, spatial immune profiling, and multi-omics approaches in patient selection. Finally, we explore future directions aimed at improving precision immunotherapy and expanding durable responses across GI cancers. Full article

Background/Objectives: Robotic surgery offers an additional minimally invasive option for gastric gastrointestinal stromal tumor (GIST) resection, particularly in anatomically demanding locations. Evidence regarding its integration into routine surgical practice remains limited. This study evaluated the evolution of surgical approaches for primary localized gastric GIST following the introduction of an institutional robotic program. Methods: We retrospectively analyzed 44 consecutive patients who underwent curative-intent resection for primary localized gastric GIST at a tertiary referral center between July 2015 and June 2025. Surgical management and perioperative outcomes were described for an early era (2015–2021; n = 29) and a later era after the introduction of robotic surgery (2022–2025; n = 15). Results: Overall, 22 procedures were completed laparoscopically, six robotically, and 13 through a primary open approach; three laparoscopic procedures were converted to open surgery. In the later era, robotic surgery accounted for 40.0% of resections, and no conversions occurred. The proportion of completed minimally invasive resections was 62.1% in the early era and 66.7% in the later era. R0 resection was achieved in all patients, and no tumor rupture was documented. Median operative time was 73.5 min, median postoperative length of stay was 7.5 days, and major morbidity occurred in six patients (13.6%). One patient (2.3%) died from sepsis within 30 days after reoperation for a postoperative gastric suture-line leak. Conclusions: Following the introduction of robotic surgery, management of primary gastric GIST evolved toward a more diversified and individualized surgical strategy. Robotic surgery was incorporated as an additional minimally invasive option, while the overall proportion of completed minimally invasive resections remained stable. These findings represent an early institutional experience and do not establish equivalence or comparative superiority among surgical approaches. Full article

Background: Substantial inter-individual variability in imatinib systemic exposure may influence both efficacy and toxicity. Based on recommendations of the International Association for Therapeutic Drug Monitoring and Clinical Toxicology (IATDMCT), the IRCCS-CRO of Aviano started in 2018 offering physicians the opportunity to monitor plasma concentrations of imatinib and its active metabolite, norimatinib, as part of a diagnostic service for patients with Gastrointestinal Stromal Tumor (GIST). This study aims to evaluate the potential clinical utility of imatinib Therapeutic Drug Monitoring (TDM) in predicting response and toxicity in a real-world cohort of 63 patients with GIST. Methods: Imatinib and its active metabolite norimatinib trough concentrations (C_min) were quantified using a validated LC–MS/MS method. Associations between drug exposure and clinical–demographic characteristics, treatment-related toxicity, and progression-free survival (PFS) were evaluated. Results: A total of 437 plasma samples from 63 patients were collected. Marked inter- and intra-patient variability in imatinib exposure was observed (43% and 31% respectively); 67% of patients receiving 400 mg/day had a C_min below the recommended target concentration (1100 ng/mL). Female sex was significantly associated with higher imatinib exposure (median C_min 1114 vs. 786 ng/mL in males; p = 0.0018). Combined age–sex analysis showed a significant difference between women and men < 60 years (1041 vs. 668 ng/mL; p = 0.0068, Bonferroni-adjusted). A strong exposure–toxicity relationship emerged, with higher imatinib levels in samples collected at toxicity occurrence vs. the others (1728 vs. 927 ng/mL; p < 0.0001), without a direct association between sex and toxicity. No significant association between C_min and PFS was observed; however, disease progression was more frequent in patients with C_min < 500 ng/mL and absent in those with C_min >1500 ng/mL (60% vs. 0%, respectively). Conclusions: TDM was found to be a potentially useful tool for predicting clinically relevant toxicity and outcome. Sex and age significantly influence exposure, supporting tailored dosing strategies. Full article

Background: NTRK gene fusions are established oncogenic drivers in a diverse spectrum of mesenchymal neoplasms. Although classically described in pediatric entities, NTRK-rearranged sarcomas also occur in adults, where their clinicopathologic features, genomic context, and response to TRK inhibition are less well characterized. Methods: We retrospectively queried a national referral genomics database to identify sarcomas in patients >18 years harboring pathogenic NTRK1, NTRK2, or NTRK3 fusions. Gastrointestinal stromal tumors, duplicate specimens, and cases lacking digitized hematoxylin and eosin slides were excluded. Fusions were identified by whole-transcriptome sequencing, co-occurring genomic alterations by exome-based sequencing, and real-world survival and time on TRK inhibitor therapy were derived from linked insurance claims data; fusion-negative sarcomas and NTRK-rearranged non-sarcoma tumors from the same database served as comparison cohorts. Results: Among 13,040 profiled sarcomas, 19 adult tumors with pathogenic NTRK fusions were identified (median age, 43 years; range, 21–77), most of which were high grade (68%) and advanced stage (63% stage IV). Histology was heterogeneous, including spindle cell sarcoma (53%), pleomorphic sarcoma (21%), and tumors corresponding to defined entities such as NF1-associated malignant peripheral nerve sheath tumor and MDM2-amplified dedifferentiated liposarcoma (11% each). NTRK1 and NTRK3 fusions were equally frequent (9 cases each); fusion partners were diverse, with TPM3 (n = 5), EML4 (n = 2), and TFG (n = 2) recurrent and other partners non-recurrent. Additional genomic alterations were common and heterogeneous (72%), including high genome-wide loss of heterozygosity and infrequent but recurrent alterations involving the TERT promoter, NF1, and RB1. All evaluable tumors showed transcriptional activation of the NTRK fusion and increased MAPK pathway activity compared with fusion-negative sarcomas. Nine patients received TRK inhibitors; median time on larotrectinib was 12.5 months, similar to that observed in NTRK-rearranged non-sarcoma tumors, but treatment duration was variable. Conclusions: Adult sarcomas harboring NTRK fusions are rare, morphologically heterogeneous, and biologically diverse. NTRK fusion status alone may not fully capture oncogenic dependence and should be interpreted within the broader clinicopathologic and genomic context. Full article

Background/Objectives: Three-dimensional (3D) reconstruction of contrast-enhanced computed tomography (CT) data has shown value in elective hepato-pancreato-biliary (HPB) surgery, but its role in complex abdominal emergencies remains poorly defined. Complex emergency HPB operations are high-acuity procedures in which precise preoperative anatomical knowledge directly influences outcome, because inadequate characterization of vascular relationships in these operations may lead to intraoperative catastrophe, unrecognized vascular injury, incomplete resection, or perioperative death. We report a retrospective proof-of-concept case series designed to test whether 3D reconstructions generated from preoperative CT datasets, when read by an operator blinded to the intraoperative findings, correspond to the intraoperative findings used as ground truth and provide anatomical information beyond the original conventional CT report. Methods: Single-center retrospective consecutive case series of five patients who underwent complex emergency HPB surgery at the Regional Institute of Gastroenterology and Hepatology “Prof. Dr. O. Fodor,” Cluj-Napoca, Romania, between July 2018 and July 2022. All operations were guided by conventional contrast-enhanced CT. Three-dimensional reconstructions were generated after surgery, from the archived preoperative CT datasets by a single reader who was blinded to the intraoperative findings, to the operative note, and to the histopathological diagnosis. The 3D reconstructions were compared qualitatively with the intraoperative findings (ground truth) and with the original radiological report. Results: Five patients (3 women, 2 men; mean age 62.2 years) were analyzed: a right colonic flexure tumor with duodenal invasion, a duodenal gastrointestinal stromal tumor (GIST), an aortoduodenal fistula, a complex bilioduodenal fistulization with right hepatic artery pseudoaneurysm, and a periampullary tumor in contact with the inferior vena cava (IVC). In all five cases the blinded 3D reconstruction corresponded closely with the intraoperative findings, whereas the original conventional CT report did not match the intraoperative ground truth as precisely—particularly with respect to the exact location, the longitudinal and circumferential extent, and the local topography of vascular involvement and of fistulous tracts. Conclusions: Under blinded retrospective comparison, post hoc 3D reconstructions—generated through independent reassessment of the archived CT imaging by a reader blinded to the intraoperative findings—corresponded more closely with intraoperative findings than the original same-day emergency CT report in depicting vascular topography across five complex emergency HPB operations. These hypothesis-generating findings motivate a prospective study of preoperative 3D reconstruction within the emergency imaging pathway. Full article

Ewing sarcoma is a highly malignant tumor whose histological appearance often overlaps with that of other undifferentiated round-cell and ovoid-cell tumors, making accurate diagnosis challenging. Selecting the most appropriate immunohistochemical and molecular tests is critical, particularly when only limited core biopsy material is available and tissue preservation for additional molecular or biomarker testing is required. Artificial intelligence (AI)-based histopathological image analysis is emerging as a promising diagnostic tool in oncology. This study evaluated the potential of AI-based histopathological analysis to assist pathologists in the morphologic classification of Ewing sarcoma and selected histological mimics using tissue microarrays (TMAs), rather than to identify or predict molecular alterations. We analyzed 1926 digitized histological cores, from 729 patients, assembled into 45 tissue microarrays. The dataset comprised 517 Ewing sarcomas (ESs), 367 rhabdomyosarcomas (RMSs), 187 chondrosarcomas (CHSs), 138 gastrointestinal stromal tumors (GISTs), and 124 synovial sarcomas (SSs). A weakly supervised multiple-instance learning (MIL) framework with transformer-based aggregation was developed using only core-level diagnostic labels. The model achieved classification accuracies of 97.1% for Ewing sarcoma, 80.0% for rhabdomyosarcoma, 85.7% for gastrointestinal stromal tumors, 80.0% for chondrosarcoma, and 76.0% for synovial sarcoma. The overall classification accuracy was 91.6%, with no misclassifications between Ewing sarcoma and rhabdomyosarcoma. These findings highlight the model’s robustness in distinguishing tumor entities that present a well-recognized diagnostic challenge in routine pathology. The AI algorithm demonstrated strong potential as a diagnostic adjunct for assisting pathologists in the morphologic classification of Ewing sarcoma and selected tumor entities based on histopathological features. Although these tumor entities are characterized by specific molecular alterations, the model was not designed to identify or predict molecular alterations directly. Instead, it supports clinical decision-making by recognizing morphologic patterns associated with diagnostically defined tumor entities. The integration of AI-based histopathological analysis with immunohistochemistry and contemporary molecular diagnostic techniques has the potential to improve diagnostic accuracy, optimize the use of ancillary testing, enhance our understanding of genotype–phenotype relationships, and ultimately support more effective patient management. Full article

Background/Objectives: Rectal gastrointestinal stromal tumors (GISTs) near the dentate line (DL) present significant surgical challenges due to anatomical constraints and difficulty preserving anal function. Endoscopic intermuscular dissection (EID) is a viable alternative in these cases. Methods: We retrospectively reviewed the medical records of patients who underwent EIDs for rectal GISTs near the DL between January 2015 and December 2023. The primary outcomes assessed were procedural efficacy—measured by en bloc and complete resection rates—and safety, evaluated regarding delayed bleeding, perforation, and tumor recurrence. Results: In total, 10 patients underwent rectal GIST EIDs. The mean tumor size, procedure time, and resection speed were 25.70 ± 14.09 mm, 81.30 ± 46.20 min, and 16.91 ± 9.94 mm²/min, respectively. The en bloc and complete resection rates were 100% and 70%, respectively. Compared with endoscopic submucosal dissection (ESD) for rectal epithelial lesions, there were no significant differences in procedure times (81.30 ± 46.20 min vs. 76.50 ± 32.42 min, p = 0.758) or complete resection rates (70% vs. 95%, p = 0.095). Regarding safety, delayed bleeding (10% vs. 10%, p = 1.000) and perforation (10% vs. 0%, p = 0.333) rates did not differ significantly between the two groups. During a median 36-month follow-up, one recurrence occurred in a patient with a high-risk GIST. Conclusions: EID for rectal GISTs near the DL appears to be a feasible and potentially safe treatment option in carefully selected patients. It may represent a less invasive alternative to surgery, particularly when preservation of anal function is a priority. Nevertheless, validation in larger prospective studies is required. Full article

Background and Clinical Significance: The primary occurrence of low-grade endometrial stromal sarcoma (LG-ESS) at extrauterine sites, termed extrauterine ESS (EESS), is exceedingly rare. Case Presentation: A 49-year-old female, gravida 2 para 2 (all deliveries by cesarean section), presented with a 1-month history of epigastric and left upper quadrant abdominal pain. Abdominal computed tomography revealed a lobulated mass, measuring 4.6 cm, in the left upper quadrant with focal attachment to the splenic flexure of the colon. She underwent a laparoscopic partial gastrectomy and colectomy at a referral institution. Surgical pathology identified a 6.0 × 5.0 × 4.0 cm lobulated tumor involving the stomach with colonic invasion, diagnosed as LG-ESS (pT3N0). Immunohistochemistry showed a CD10-reactive lesion. The patient was referred to our institution for definitive gynecological surgery. After prophylactic ureteral double-J catheter insertion, she underwent laparoendoscopic single-site (LESS) total hysterectomy with bilateral salpingo-oophorectomy. The final histopathological examination of the hysterectomy specimen revealed intramural leiomyomas and benign ovarian cysts, with no evidence of ESS within the uterine corpus or adnexa. These findings confirmed a true primary EESS of nonuterine origin, consistent with AJCC stage 3 disease. The patient recovered uneventfully and was discharged during outpatient follow-up. Conclusions: This case represents one of the very few reported instances of primary LG-EESS involving the stomach and colon, simultaneously managed with a staged multidisciplinary surgical approach, including gastrointestinal resection followed by LESS hysterectomy and bilateral salpingo-oophorectomy. Full article

Neuroendocrine neoplasms (NENs) are a heterogeneous family of tumors that have traditionally been regarded as “immune cold” and largely refractory to PD-1/PD-L1 checkpoint blockade, with notable exceptions such as Merkel cell carcinoma (MCC). The advent of single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics has enabled unprecedented dissection of the NEN tumor microenvironment (TME), but a cross-subtype synthesis is lacking. This review aims to integrate single-cell and spatial transcriptomic findings across major NEN subtypes to reframe NEN immunosuppression and delineate translational implications. To this end, we performed a structured narrative review of PubMed-indexed studies up to 30 April 2026, prioritizing original human scRNA-seq, single-nucleus RNA-seq, spatial transcriptomic, and spatial proteomic studies of NENs, supplemented by mechanistic, clinical, and biomarker-focused reports providing essential context. Across these studies, synthesis spanning pancreatic, pulmonary, gastrointestinal, cutaneous, pituitary, adrenal, and other NEN subtypes highlights conserved features beyond the PD-1/PD-L1 axis, including myeloid-dominated infiltration with alternative checkpoints (VISTA, TIM-3, Galectin-9), cancer-associated fibroblast-mediated immune exclusion, lineage-state-dependent immune visibility, and direct immunomodulation by neuroendocrine secretory products such as calcitonin gene-related peptide. We propose a four-layer framework integrating these mechanisms and linking them to emerging biomarkers and therapies, including DLL3-directed bispecifics, alternative checkpoint inhibitors, stromal-targeting agents, and peptide receptor radionuclide therapy combinations. Together, these findings indicate that single-cell and spatial transcriptomic studies reframe NEN immunosuppression as a multilayered, subtype-dependent process, providing a conceptual scaffold for biomarker-guided, subtype-adapted therapeutic strategies and prospective clinical trial design in neuroendocrine oncology. Full article

Inflammatory fibroid polyp (IFP) or Vanek’s tumor is a rare benign submucosal lesion of the gastrointestinal tract that may radiologically mimic mesenchymal gastric tumors, particularly gastrointestinal stromal tumors. We present the case of a 65-year-old patient with a contrast-enhancing gastric submucosal mass detected on computed tomography, initially interpreted as a suspected mesenchymal neoplasm. CT imaging demonstrated a well-defined enhancing lesion arising from the gastric wall without evidence of metastatic disease. Surgical resection was performed because imaging findings were considered highly suggestive of GIST. Gross intraoperative appearance and pathological examination, however, established the final diagnosis of gastric inflammatory fibroid polyp (Vanek’s tumor). Histopathological analysis demonstrated characteristic spindle-cell proliferation with inflammatory eosinophil-rich infiltrates, while immunohistochemistry excluded GIST. This case highlights the diagnostic challenge in differentiating IFP from other gastric submucosal neoplasms based solely on imaging findings and emphasizes the importance of histopathological confirmation for definitive diagnosis. Full article

Background: Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms, accounting for approximately 1–3% of all gastrointestinal tumors, with an annual incidence of 1–2 cases per 100,000 population worldwide. They arise from the interstitial cells of Cajal and are most commonly located in the stomach and small intestine. Methods: We report a case of a 39-year-old man admitted with a preliminary diagnosis of an appendiceal inflammatory mass with suspected abscess formation. Results: The patient presented with right iliac fossa pain, fever, signs of pronounced systemic intoxication and laboratory findings consistent with inflammatory syndrome. Abdominal computed tomography revealed a mass in the right iliac region with infiltration of the surrounding adipose tissue, suggestive of an appendiceal infiltrate. Emergency surgical exploration identified a tumor originating from the cecum. Radical resection of the ileocecal region with side-to-side ileo-ascending anastomosis was performed. Histopathological examination confirmed a spindle-cell variant of GIST. The postoperative course was uneventful. Conclusions: This case highlights the diagnostic challenges of atypically localized GISTs, which may clinically and radiologically mimic inflammatory conditions such as appendiceal infiltrate. Conventional imaging modalities may be insufficient for definitive differential diagnosis. Surgical resection remains the cornerstone of treatment, with histopathological and immunohistochemical evaluation establishing the final diagnosis. Early identification and complete tumor excision are essential for optimizing clinical outcomes and long-term prognosis. Adjuvant therapy with tyrosine kinase inhibitors should be considered based on individual recurrence risk. Full article

A 66-year-old woman was referred for evaluation of a large pelvic mass suspected to be ovarian cancer. Contrast-enhanced computed tomography (CECT) revealed a giant multiseptated cystic pelvic mass with enhancing solid components; although its superior aspect closely abutted the gastric serosa, its predominant pelvic location raised concern for an adnexal malignancy. Subsequent [¹⁸F]fluorodeoxyglucose positron emission tomography/computed tomography ([¹⁸F]FDG PET/CT) demonstrated mild uptake confined to the viable solid portion (SUVmax 2.72) without hypermetabolic nodal or distant metastases. Exploratory laparotomy revealed a giant pedunculated tumor arising from the gastric antrum and descending into the pelvis. Histopathology confirmed an epithelioid gastrointestinal stromal tumor positive for CD117, DOG1, and CD34. This case highlights an important diagnostic pitfall in which a giant exophytic gastric GIST may mimic ovarian cancer because of its pelvic location and cystic-solid appearance. Careful correlation of CECT, fused [¹⁸F]FDG PET/CT, and pathologic findings is essential for accurate assessment of the organ of origin in large abdominopelvic masses. Full article