Kivilcim Eren Erdogan

Claudin 18.2 (CLDN18.2) is an emerging therapeutic biomarker in gastric adenocarcinoma. This study evaluated the concordance of CLDN18.2 expression between pretreatment biopsies and corresponding resection specimens and explored its associations with clinicopathological features and survival outcomes. This retrospective single-center study included 71 patients, 58 of whom received neoadjuvant chemotherapy. CLDN18.2 positivity was defined as moderate-to-strong (2+/3+) membranous staining in ≥75% of tumor cells. Concordance was assessed using Cohen’s kappa, positive percent agreement (PPA), negative percent agreement (NPA), and intraclass correlation coefficient (ICC). CLDN18.2 positivity was identified in 26.8% of biopsies and 21.1% of resection specimens. Categorical status was concordant in 65 of 71 patients (91.5%; κ = 0.769; p < 0.001), with a PPA of 73.7% and an NPA of 98.1%. Continuous analysis showed a high ICC (0.817; 95% confidence interval (CI), 0.722–0.881; p < 0.001). Six patients had discordant categorical results, all of whom had received neoadjuvant therapy. Exploratory survival analyses did not identify a statistically significant association between pretreatment biopsy CLDN18.2 status and overall survival (OS) or recurrence-free survival (RFS); however, the limited sample size and statistical precision preclude definitive conclusions regarding its prognostic significance. Overall, CLDN18.2 showed substantial biopsy–resection concordance, although positive agreement was lower than negative agreement. Discordant findings should be interpreted cautiously because treatment-related effects cannot be distinguished from spatial heterogeneity and sampling variation.

Aim: Gastrointestinal stromal tumors (GISTs) exhibit marked heterogeneous clinical behavior that is not fully captured by conventional risk classification systems. This study aimed to evaluate the prognostic significance of loss of p16 expression and EZH2 overexpression and their relationship with clinicopathological parameters in GIST.Methods: In this retrospective study, 113 GIST cases diagnosed at a single institution between 2016 and 2026 were evaluated. Expression of p16 and EZH2 was evaluated immunohistochemically and correlated with clinicopathological parameters and overall survival using Kaplan-Meier and Cox regression analyses.Results: p16 loss was detected in 34 cases (30.1%) and EZH2 overexpression in 12 cases (10.6%). Both markers were significantly correlated with high mitotic activity, tumor necrosis, metastasis, multifocality, a high AFIP risk category, and elevated Ki-67 proliferation index (p

Introduction: Extraosseous osteosarcoma (ESOS) is a rare soft-tissue sarcoma that produces osteoid without any anatomical relationship to the skeleton. Primary gastric ESOS is exceptionally rare and presents major clinical, radiological, and pathological diagnostic challenges.Case Presentation: A 78-year-old man with six months of nonspecific gastrointestinal symptoms was found to have a 14×16×21 cm gastric mass invading the left hepatic lobe, pancreas, duodenum, and omentum. Endoscopic ultrasound–guided fine-needle aspiration was non-diagnostic. After massive upper gastrointestinal hemorrhage with hemodynamic instability, life-saving emergency laparotomy with R2 debulking was performed. Histopathology and SATB2-positive immunohistochemistry confirmed high-grade extraosseous osteosarcoma. PET-CT showed no distant or skeletal lesion, supporting a primary gastric origin.Conclusion: Primary gastric ESOS may present as a giant, multivisceral mass with non-diagnostic biopsies. Awareness, multidisciplinary evaluation, and timely surgery are critical, as resectability remains the principal prognostic determinant.Keywords: Gastrointestinal Hemorrhage; Osteosarcoma; Sarcoma; Soft Tissue Neoplasms; Stomach Neoplasms.

Background/Objectives: Claudin 18.2 (CLDN18.2) has emerged as a clinically actionable therapeutic target in gastrointestinal malignancies; however, its expression profile and prognostic significance in cholangiocarcinoma (CCA) remain incompletely characterized. This study investigated CLDN18.2 expression in CCA and evaluated its associations with clinicopathological characteristics and overall survival (OS). Methods: This retrospective study included 124 patients with histologically confirmed CCA who were diagnosed between 2010 and 2025. CLDN18.2 expression was assessed by immunohistochemistry using two predefined positivity thresholds (≥10% and ≥75% of tumor cells showing moderate-to-strong membranous staining). Associations with clinicopathological variables were analyzed, and prognostic significance was evaluated using Kaplan–Meier survival analysis and Firth’s penalized Cox regression. Results: Using a 10% cutoff, CLDN18.2 positivity was detected in 10.5% (13/124) of cases; using a 75% cutoff, it was detected in 4.8% (6/124) of cases. At the 75% threshold, CLDN18.2 expression was significantly associated with anatomical location (p = 0.013) and histological subtype (p = 0.002), with the highest positivity observed in perihilar CCA (30.0%) and large-duct intrahepatic CCA (21.7%). The median OS was 9.5 months. CLDN18.2 positivity was not significantly associated with mortality in a univariable Firth’s penalized Cox regression at either the 10% cutoff (hazard ratio (HR) = 1.641, 95% confidence interval (CI): 0.883–2.816; p = 0.112) or the 75% cutoff (HR = 1.884, 95% CI: 0.762–3.877; p = 0.155). In multivariable Firth’s penalized Cox regression, CLDN18.2 positivity at the 10% cutoff was independently associated with an approximately two-fold increased risk of mortality (HR = 2.072, 95% CI: 1.090–3.666; p = 0.028), whereas no independent prognostic significance was observed at the 75% cutoff (HR = 1.906, 95% CI: 0.768–3.951; p = 0.150). The absence of adjuvant therapy was independently associated with increased mortality in both models (10% cutoff: HR = 4.870, 95% CI: 1.671–13.784; p = 0.004; 75% cutoff: HR = 4.296, 95% CI: 1.521–11.899; p = 0.006). Conclusions: CLDN18.2 expression in CCA varies according to anatomical location, histological subtype, and positivity threshold. The relatively high expression observed in perihilar CCA, and large-duct intrahepatic CCA, and the independent prognostic significance identified at the 10% cutoff support the potential role of CLDN18.2 as a prognostic biomarker and therapeutic target in selected patients with CCA. Given the limited sample sizes in some anatomical and histological subgroups, these findings should be interpreted cautiously and validated in larger prospective multicenter studies.

Purpose:Amyloidosis comprises a heterogeneous group of disorders characterized by extracellular deposition of misfolded proteins, which may result in progressive organ dysfunction. Gastrointestinal involvement is uncommon and often presents with non-specific symptoms, making diagnosis challenging. Involvement of the mesentery and omentum is particularly rare.Case Presentation:A 29-year-old male with a known history of Crohn’s disease and Familial Mediterranean Fever (FMF) presented with nausea, vomiting, and inability to pass gas or stool. Radiological evaluation revealed intestinal obstruction accompanied by nodular lesions in the mesentery and omentum. Due to persistent clinical findings, surgical intervention was performed, including adhesiolysis and omental biopsy. Histopathological examination confirmed amyloid deposition. The patient had an uneventful postoperative course and was discharged on the fifth day.Conclusion:This case highlights a rare presentation of AA amyloidosis involving the gastrointestinal tract, mesentery, and omentum in the setting of chronic inflammatory disease. Amyloidosis should be considered in the differential diagnosis of patients with unexplained gastrointestinal symptoms, particularly in those with underlying inflammatory conditions. Early diagnosis and histopathological confirmation are crucial for appropriate management and improved prognosis.

Background: Desmoid tumors (DT) are rare, locally aggressive neoplasms characterized by an unpredictable clinical course. Although anatomical localization has been associated with tumor behavior, its relationship with systemic inflammatory response remains insufficiently explored. This study aimed to evaluate the impact of tumor localization on systemic inflammatory markers and to investigate CD47 expression in DT. Methods: This retrospective cohort study included 127 patients diagnosed with DT between 2010 and 2023. Demographic, clinicopathological, and laboratory data were collected. Systemic inflammatory indices, including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), prognostic nutritional index (PNI), HALP score, and pan-immune-inflammation value (PIV), were calculated. Tumor localization was categorized as trunk, extremity, or head and neck. CD47 expression was evaluated by immunohistochemistry. Results: Tumors were most frequently located in the trunk (50.4%), followed by extremities (40.9%) and head and neck region (8.7%). Significant differences in inflammatory markers were observed according to tumor localization. The head and neck group demonstrated lower neutrophil counts (p = 0.020), NLR (p = 0.009), PLR (p < 0.001), and PIV (p = 0.003), while showing higher PNI (p = 0.043) and HALP scores (p = 0.001) compared to trunk-localized tumors. Additionally, smaller tumors (p = 0.041) and neutrophil counts (p = 0.015). No detectable CD47 expression was observed in any tumor samples. Conclusions: Anatomical localization is closely associated with distinct systemic inflammatory profiles in patients with DT. These findings suggest that tumor location may influence host immune–inflammatory interactions and contribute to the biological heterogeneity of DT. The absence of CD47 expression indicates that alternative immune-related mechanisms may play a role in DT biology. Easily accessible inflammatory markers may provide valuable insights for risk stratification in clinical practice.

Dedifferentiated liposarcoma (DDLPS) can exhibit myxoid morphology that closely mimics myxoid liposarcoma (MLPS), creating significant diagnostic challenges. DDIT3 immunohistochemistry (IHC), a specific marker for MLPS, has been reported in a subset of DDLPS cases, but its frequency, staining pattern, and clinical significance remain poorly characterised. We retrospectively analysed 46 DDLPS cases with prominent myxoid features (≥ 10% myxoid component) confirmed by MDM2 IHC and fluorescence in situ hybridisation (FISH), treated at a single tertiary centre between January 2007 and January 2026. DDIT3 IHC was scored using a semiquantitative H-score system. DDIT3 positivity occurred in 11 of 46 cases (23.9%, 95% CI: 12.6–38.8%), predominantly as focal staining (9/11, 81.8%). All DDIT3-positive cases exhibited myxoid components comprising > 25% of tumour volume, versus variable myxoid extent in DDIT3-negative cases (p < 0.001). Mean H-score in DDIT3-positive cases was 48.6 ± 32.4 (range 15–120), significantly lower than in true MLPS controls (mean 278 ± 22, p < 0.001). Tumour size > 15 cm significantly increased the risk of local recurrence (risk ratio [RR] = 2.31, 95% CI: 1.02–5.24, p = 0.048). DDIT3 expression showed no significant association with local recurrence (p = 0.337), distant metastasis (p = 0.825), or mortality (p = 0.805). Kaplan–Meier analysis revealed no significant difference in overall survival (log-rank p = 0.782) or recurrence-free survival (log-rank p = 0.614) between DDIT3-positive and DDIT3-negative groups. DDIT3 positivity in DDLPS with myxoid features predominantly produces focal, low-intensity staining that distinguishes it from true MLPS. DDIT3 expression reflects chromosomal co-amplification within the 12q13-15 amplicon and lacks prognostic significance. Combined MDM2 and DDIT3 IHC with careful morphological assessment aids differential diagnosis, particularly when molecular testing is unavailable.

The aim of our study is to evaluate the effects of glutamine, partially hydrolyzed guar gum and combined glutamine and partially hydrolyzed guar gum form in rats with experimental radiation enteritis by histopathological, immunohistochemical and biochemical measurements. 64 Wistar albino rats with an average weight of 220–280 g were used in the study. 1st group only took water, 2nd group only took glutamine, 3rd group only took partially hydrolyzed guar gum, 4th group took partially hydrolyzed guar gum with glutamine, 5th group took only radiotherapy, 6th group took radiotherapy with glutamine, 7th group took radiotherapy with partially hydrolyzed guar gum and 8th group took radiotherapy, glutamine and guar gum. Partially hydrolyzed guar gum was given with radiotherapy, and glutamine and guar gum were given together with radiotherapy in the 8th group. All rats were weighed on the first, seventh and tenth days. On the tenth day, the rats were sacrificed and their clinical status, biochemical, histopathological and immunohistochemical parameters in the terminal ileum were evaluated. Differences between groups were compared statistically. All groups were compared in terms of crypt length, villus height, crypt abscess, congestion, intraepithelial lymphoid infiltration, stool consistency, myeloperoxidase, malondialdehyde, caspase-3% and tumor necrosis factor alpha mean, and statistical significance was observed (p < 0.05). Weight% difference in rats was statistically significant between groups (p < 0.05). Interleukin-10 values were not statistically significant between groups (p > 0.05). In paired comparisons, there was a statistically significant difference between the control group and the group with radiation enteritis in terms of biochemical, histopathological, immunohistochemical and clinical parameters (p < 0.05). There was no statistically significant difference between the 5th group and 6th group, 7th group and 8th groups in terms of biochemical, histopathological, immunohistochemical and clinical parameters (p > 0,05). The result suggest that glutamine, partially hydrolyzed guar gum and combination therapy may not have a protective effect on radiation enteritis.

Purpose: To evaluate the effects of intraperitoneal Hypericum perforatum oil (St. John’s Wort oil, SJWO) on systemic inflammation and peritoneal histopathology in experimental peritonitis. Methods: Forty-two male Wistar Albino rats were randomized into seven groups (n = 6): control, SJWO, olive oil, peritonitis, peritonitis + saline, peritonitis + SJWO, and peritonitis + olive oil. Peritonitis was induced with freshly prepared autologous fecal suspension, and treatments were administered intraperitoneally at 48 h. On day 5, plasma inflammatory markers, peritoneal thickness, and histopathological scores were assessed blinded. Results: The greatest weight loss was seen in the peritonitis group (p = 0.002). SJWO did not consistently reduce systemic inflammatory markers. Compared with peritonitis + saline, peritonitis + SJWO showed lower parietal fibrosis and vascular proliferation scores (rank-biserial correlation for each outcome, r rb = -0.833; 95% confidence interval -1.000 to -0.500), but visceral fibrosis was not reduced. Conclusion: Intraperitoneal SJWO did not suppress systemic inflammation. The lower early parietal fibrosis and vascular proliferation scores are exploratory because the effect was not observed in visceral tissue, and adhesion formation was not directly assessed.

Objective: Giant cell tumor of the bone (GCTB) is a locally aggressive benign tumor with unpredictable recurrence patterns. While intraos seous recurrences are well-documented, soft tissue recurrence (STR) remains underrecognized. This study aimed to identify risk factors, radiographic features, and histopathological characteristics associated with STR of GCTB. Methods: This retrospective study included 69 patients treated for GCTB between 1996 and 2022. Demographic data, tumor location, sur gical method, recurrence history, and adjuvant treatments were extracted from medical records. Radiologic assessments were performed using a picture archiving and communication system, and lesions were graded by Campanacci classification. Histopathological evalua tion included H3F3A immunohistochemistry in cases with STRs. Statistical analysis was performed using chi square, Fisher’s exact, and Mann–Whitney U-tests. Results: The initial surgical approach was curettage in 55 patients (79.7%), resection in 14 (20.3%). Recurrence occurred in 24 patients (34.8%), and STR was identified in 7 (10.1%). Most STRs were located near the distal femur. Among these, 4 had prior intraosseous recur rence, and 5 had Campanacci grade 3 lesions. No statistically significant association was found between STR and variables including age, sex, tumor volume, Campanacci grade, tumor location, denosumab, or local adjuvant use. H3F3A analysis was performed in 6 out of 7 patients with STR, and positivity was detected in 3 of them. Pulmonary metastasis was documented in 8 patients overall, including 3 of 7 with STR (42.9%) compared with 5 of 62 without STR (8.1%), representing a significant difference. Conclusion: Soft tissue recurrence in GCTB may occur independently or following intraosseous recurrence and is frequently observed in high-grade lesions. Although not statistically significant, the findings suggest a possible association between tumor aggressiveness and STR. Histological features remain consistent with osseous lesions, but the diagnostic value of H3F3A expression in STRs warrants fur ther investigation. Importantly, STR represents a distinct recurrence pattern and may be associated with an increased risk of pulmonary metastasis, underscoring the need for vigilant long-term follow-up and systematic surveillance. Cite this article as: Mirioğlu A, Dalkır KA, Ölke HC, et al. Soft tissue recurrence in giant cell tumor of bone: risk factors and radiological and histopathological features. Acta Orthop Traumatol Turc., 2025;59(6):470-476.