We report a case of mismatch repair protein deficient (MMRd) and high microsatellite instability (MSI-H) GIST that is exceedingly rare. The patient is an elderly male who presented with abdominal discomfort and poor appetite. Investigations revealed a gastric GIST (CD117 and DOG1 positive, SDH expression retained), spindle cell type, 22cm in size with 23 mitoses per 5mm2. Few small metastatic nodules were also present in the liver. Next generation sequencing (NGS) revealed a KIT exon 11 c.1668_1724del, p.(Trp557_Gln575del) variant, MSI-H phenotype and tumour mutational burden (TMB) of 15.7 mutations per megabase (Mb). MMR protein immunohistochemistry showed loss of MLH1 and PMS2 expression. The NGS also showed a MLH1 exon 17 c.1946del, p.(Pro649fs) variant. No germline testing was performed. MSI testing by MSI PCR, however, showed a microsatellite stable result. This highlights how MSI PCR may not be sufficiently sensitive in detecting MSI-H status in tumour types outside of colorectal carcinomas.

This study aimed to explore the clinicopathological characteristics, immunophenotype, histologic occurrence, diagnosis, and differential diagnosis of the Warthin-like variant of papillary thyroid carcinoma. The clinical features, thyroid fine-needle aspiration cytology, histomorphology, and immunohistochemistry results of 4 cases of Warthin-like variant of papillary thyroid carcinoma were analyzed, and related published studies were reviewed. Three of the 4 patients were female and one male, aged 46 to 73 years, with a median age of 61.5 years. The tumors were 0.8 to 1.5cm in size and gray-white, solid or partially cystic nodules with a hard texture. The microscopic examination revealed tumor cells in the context of Hashimoto thyroiditis, which were histologically similar to Warthin tumor of the salivary glands, with a large number of lymphocytes and some plasma cells in the papillary structure. The tumor cells had features typical of papillary carcinoma, with abundant and eosinophilic cytoplasm. The results of the immunohistochemical analysis were as follows: TTF-1, CK19, and galectin-3 were positive, whereas thyroglobulin and CD56 were negative. Warthin-like variant of papillary thyroid carcinoma is a rare thyroid malignancy. Its unique morphology is helpful for diagnosis and differential diagnosis, and its prognosis is relatively good.

Thermal ablation has become an important treatment option for early-stage hepatocellular carcinoma with the development of interventional ultrasound technology. However, in the treatment of medium-to-large-volume tumors, intrahepatic cholangiocarcinoma, and high-risk anatomical sites, it still faces clinical bottlenecks such as high recurrence rates and difficulties with margin control. This article discusses current clinical difficulties and explores indication expansion and coping strategies for various ablation techniques. The "no touch" strategies of radiofrequency ablation and microwave ablation have shown an overall survival period that is comparable to that of surgery for medium or multiple tumors that are 3 to 5 cm in size. Microwave ablation and repeated surgical resection that meets the Milan criteria have similar overall and disease-free survival rates in patients with intrahepatic cholangiocarcinoma. Non-thermal ablation techniques such as irreversible electroporation offer safe alternatives for refractory lesions adjacent to large blood vessels or bile ducts due to their characteristics of no heat-sink effect and preservation of collagen scaffolds. Image fusion navigation and synergistic "ablation plus immunotherapy" may be key directions for overcoming local control bottlenecks and improving long-term prognosis in the future.

Fibromatosis-like metaplastic carcinoma (FLMC) of breast is a rare neoplasm that exhibits distinct low-grade cytomorphology, a tendency for local recurrence and a favorable prognosis. This retrospective study aimed to evaluate the clinicopathological and immunohistochemical features of FLMC and assess its clinical behavior. Six female patients with histologically confirmed FLMC were included. Hematoxylin and eosin-stained slides were reviewed, and immunohistochemistry for keratin AE1/AE3, keratin CAM5.2, keratin 5/6, p63, EMA, ACTA1, desmin, and CD34 was performed. The mean age was 57.3 years, and all patients presented with a painless breast mass. Tumors were firm, unencapsulated, and averaged 4.9 cm in size on gross examination. Microscopically, they showed bland spindle cells in fascicular and storiform patterns with infiltrative borders. All tumors were positive for keratin AE1/AE3, keratin CAM5.2, and p63. EMA was positive in 1/3 tumors, keratin 5/6 in 3/3, ACTA1 in 2/3. All tumors were negative for desmin and CD34. No nodal metastasis was identified. On follow-up, one patient developed bone metastasis after 2 years, while the others remained disease-free 3 years post-surgery. FLMC is a rare low-grade epithelial malignancy that can mimic benign spindle cell lesions, making immunohistochemistry essential for diagnosis. Complete surgical excision with clear margins is curative in most patients.

For typeI gastric neuroendocrine neoplasms (gNEN) larger than 1 cm endoscopic resection should be performed, whereas for tumors larger than 2 cm surgical resection should be carried out. Tumors between 1and 2 cm in size are generally resected endoscopically following endosonography; however, surgery should be considered in the presence of risk factors such as G2/3 tumors, infiltration of the muscularis propria and vascular invasion. TypeII gNENs are treated endoscopically or surgically in the same manner as typeI tumors. It is essential to consider treatment of the underlying hypergastrinemia caused by duodenal wall gastrinomas as well as treatment of any potentially concurrent primary hyperparathyroidism (pHPT). For typeIII gNENs surgical resection is generally recommended. In selected patients with very rare, small (< 1 cm) G1 tumors, endoscopic resection can be appropriate.

Oral and maxillofacial schwannoma (OMSCH): An institutional study of 102 patients.

Management of the axilla in early-stage breast cancer has progressively evolved toward less invasive approaches, as advances in tumor biology, imaging, and local and systemic therapies have improved outcomes while highlighting the morbidity associated with axillary surgery. Sentinel lymph node biopsy, once considered essential for staging, is increasingly being questioned in select patients with clinically node-negative disease. This review summarizes current evidence evaluating omission of sentinel lymph node biopsy in early-stage breast cancer, including its impact on oncologic outcomes, quality of life, and implementation in clinical practice. Multiple retrospective studies and randomized controlled trials have demonstrated that omission of axillary surgery does not compromise survival outcomes in carefully selected patients with hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative tumors. These findings informed the 2016 Choosing Wisely® recommendation by the Society of Surgical Oncology to avoid routine sentinel lymph node biopsy in women over 70 years of age with clinically node-negative disease. While implementation of this guideline was slower than expected, subsequent studies have explored whether sentinel lymph node biopsy can be safely omitted in a broader group of women with early-stage, HR-positive/HER2-negative invasive breast cancers, who are clinically node-negative on physical exam and preoperative axillary ultrasound. This led to the development of several prospective trials, including SOUND (Sentinel Node vs Observation After Axillary Ultra-Sound), INSEMA (Intergroup Sentinel Mamma), NAUTILUS (No Axillary Surgical Treatment in Clinically Lymph Node Negative Patients on Ultrasonography After Neoadjuvant Chemotherapy), BOOG 2013-08 (Dutch Breast Cancer Research Group 2013-08), OMSLNB (Omission of Sentinel Lymph Node Biopsy), VENUS, and SOAPET (Sentinel node biopsy vs. observation after axillary PET). While many of these trials remain ongoing, results of the SOUND and INSEMA trials demonstrate no difference in survival outcomes following omission of sentinel lymph node biopsy in postmenopausal women with low grade, HR-positive/HER2-negative tumors less than 2 cm in size, and these findings are increasingly being incorporated into clinical practice. Advancements in neoadjuvant therapies have resulted in increasing rates of pathologic complete response in the breast in clinically node-negative women with HER2-positive and triple-negative breast cancers, raising the possibility that sentinel lymph node biopsy may be safely omitted in this population as well. This is being investigated in the EUBREAST-01 (European Breast Cancer Research Association of Surgical Trialists), ASICS (Avoiding Sentinel lymph node biopsy In select Clinical node negative breast cancer patients after neoadjuvant Systemic therapy), ASLAN (Avoid Axillary Sentinel Lymph Node Biopsy After Neoadjuvant Chemotherapy), and Neo-NAUTILUS trials. While these trials are ongoing, the results are promising to change the scope of current clinical practice and reduce the morbidity associated with axillary surgery in appropriately selected patients with breast cancer.

To evaluate the long-term outcomes of selective trans-arterial embolization (SAE) in patients with giant (⩾10 cm in size) renal angiomyolipomas (AMLs) at our tertiary referral center. This retrospective, single-center study included 44 patients who underwent SAE for AMLs of ⩾10 cm size between July 2018 and June 2024. Collected data included demographics, tumor characteristics, clinical symptoms, type of intervention, tumor size before and after embolization, and renal function. Outcomes assessed were tumor size reduction, preservation of renal function, reintervention rates during follow-up and complications following SAE. The study included 46 tumors in 44 patients. Mean patient age was 40.4 years (range: 23-60), with 86.3% being females. Mean follow-up duration was 25.2 months (range: 6-70 months). Eleven patients (25%) were associated with TSC, and all were offered Everolimus postoperatively. The mean tumor size decreased significantly from 13.2 ± 3.12 cm pre-embolization to 10.3 ± 2.45 cm post-embolization (p = 0.003). Renal function remained stable during follow-up, with no significant changes in serum creatinine (p = 0.6) and eGFR (p = 0.8). The overall success rate was 84.7%, with 13.6% experiencing re-intervention. Complications included post-embolization syndrome (43.1%) and allergic reactions (6.8%), while one patient required nephrectomy due to a perinephric abscess. Selective Trans-arterial Embolization is a safe and effective treatment for giant renal AMLs, resulting in significant tumor size reduction, symptom relief, and preservation of renal function. It offers a minimally invasive alternative to traditional surgical approaches, particularly for patients with high surgical risk or those requiring nephron-sparing procedure.

Purpose To evaluate the safety and efficacy of transcatheter CT hepatic arteriography (angio-CT)-guided percutaneous microwave ablation (AA) for small hepatocellular carcinoma tumors and compare its outcomes with those of conventional CT-guided microwave ablation (CA). Materials and Methods The authors performed a retrospective review of patients with hepatocellular carcinoma tumors less than 3 cm in size treated with AA and CA from June 2019 to August 2024 at a single institution. Hepatic arteriography was performed after transarterial catheterization in an angio-CT hybrid suite. CA was performed with or without US. The authors evaluated the target-lesion radiologic response according to modified Response Evaluation Criteria in Solid Tumors criteria at follow-up contrast-enhanced CT or MRI. Target-lesion progression-free survival (PFS) and overall survival were calculated using the Kaplan-Meier method. Cox regression hazard models were used to identify variables associated with PFS. Adverse events were retrospectively reviewed. Results A total of 70 patients and 85 tumors were included in this study (mean age, 63.2 years ± 9.5 [SD]; 49 male patients). Thirty-six tumors (27 patients) were treated with AA. Forty-nine tumors (43 patients) were treated with CA. The 3-month complete response rate (100% vs 79.6%; P = .0042) and the 2-year PFS rate (95.8% vs 68.5%; log-rank P = .0099) were higher for the AA group than the CA group. Overall survival was similar between the groups (log-rank P = .583). In the multivariable analysis, AA but not CA was independently associated with increased PFS (P = .009). One patient from the CA group developed hemorrhagic shock after ablation. No other severe adverse events or grade 3 or above hepatic toxicities occurred. Conclusion For hepatocellular carcinoma tumors less than 3 cm in size, AA resulted in higher initial response and PFS rates than CA with comparable safety profile. Keywords: Angio-CT, Hepatocellular Carcinoma, Microwave Ablation Supplemental material is available for this article. © RSNA, 2026.

Oncologic outcomes and the impact of minimally invasive surgery in early-stage cervical cancer patients undergoing radical trachelectomy: A retrospective multicenter cohort study from the Korean Gynecologic Oncology Group Study (KGOG 1048).

Mucinous cystic neoplasm of the liver (MCN-L) is an uncommon cystic tumor with low malignant potential that mainly occurs in women. Because many patients have few or no symptoms and imaging findings may look similar to simple liver cysts or other cystic lesions, it is easy to make an incorrect diagnosis before surgery. A 36-year-old woman had no discomfort. A large cystic liver lesion was found by chance during a routine health checkup. She did not report abdominal pain, distension, fever, jaundice, or weight loss. Imaging examinations showed a giant multilocular cystic mass about 20 cm in size in segment IV of the liver, with septal enhancement. Serum carbohydrate antigen 19-9 (CA19-9) was markedly increased (553 IU/mL), while other tests were unremarkable. MCN-L was suspected. Histopathology of the resected specimen confirmed a low-grade MCN-L with ovarian-type stroma, and immunohistochemistry showed estrogen and progesterone receptor positivity in the stromal cells. Because the tumor was very large and located close to major hepatic vessels, the patient underwent open segment IV hepatectomy. The whole cystic lesion was removed en bloc without rupture. The postoperative recovery was smooth, without bleeding, bile leakage, or infection. During 24 months of follow-up, abdominal computed tomography and serum CA19-9 were checked every 6 months. No tumor recurrence or metastasis was observed, and CA19-9 returned to the normal range. The patient's quality of life remained good. When a very large hepatic cystic lesion is identified in a young woman, especially with elevated CA19-9 and septal enhancement on magnetic resonance imaging, MCN-L should be considered in the differential diagnosis. Because preoperative diagnosis can be difficult, careful assessment of lesion size, internal architecture, and its relationship to major vessels is essential. Complete surgical resection with negative margins remains the preferred treatment, as it reduces the risks of recurrence and malignant transformation.

Abstract Introduction Lung cancer is the second most common cancer in men, with diagnosis under 40 years of age being relatively uncommon. Here we discuss the diagnostic challenges involved in a young patient presenting with hemoptysis, who was found to have rapidly progressive adenocarcinoma of the lung. Description A 38-year-old African American male with a prior history of treated blastomycosis of the left lung, was admitted to our hospital for evaluation of intermittent hemoptysis, that started a few weeks prior. He had a 10-pack-year smoking history and was previously incarcerated. On admission, his vital signs and physical examination were unremarkable. Computed Tomography (CT) pulmonary angiogram showed a right upper lobe ground glass opacity measuring 5 cm in size with adjacent posterior right apical pleural thickening, which was suggestive of an infectious process or pulmonary hemorrhage. He subsequently underwent bronchoscopy with bronchoalveolar lavage (BAL) with unremarkable results, including culture data and cytology. Due to persistence of his symptoms, a transbronchial cryobiopsy of the right upper lobe lesion was performed, which was concerning for adenocarcinoma. Endobronchial ultrasound (EBUS) was negative for right hilar and mediastinal involvement. Positron Emission Tomography-Computed Tomography (PET-CT) was suggestive of a primary lung malignancy in the right upper lobe with right supraclavicular lymphadenopathy, extensive right pleural involvement, and malignant pleural effusion. He was initiated on weekly chemotherapy and palliative radiotherapy for bone and pleural metastasis and showed marked interval response to therapy. Discussion Non-small cell lung cancer (NSCLC), especially adenocarcinoma, can present as an infectious or inflammatory process, especially in younger individuals. This causes diagnostic challenges and as a result, these patients are usually diagnosed at an advanced stage of cancer with increased rates of mortality. Our patient presented with hemoptysis as the sole manifestation, with imaging that showed a right upper lobe ground glass opacity. Given his age and previous history of blastomycosis, a recurrence of infection was high in the differential diagnosis, with very low suspicion for malignancy. Moreover, initial bronchoscopy with BAL was unremarkable for infectious etiology and had negative cytological examination. The persistence of symptoms including hemoptysis led to further evaluation, including a transbronchial cryobiopsy that revealed the diagnosis. This case emphasizes the need for vigilance and additional testing in young patients presenting with atypical features, as an early diagnosis of lung cancer can improve their survival rates and overall prognosis. This abstract is funded by: None

Prevalence and Risk Factors for Udder Cleft Dermatitis in UK Dairy Herds.

BackgroundOne of the most common primary tumor sources of brain metastases (BMs) is lung cancer. As certain magnetic resonance imaging (MRI) features overlap between the pathological and genetic subtypes of lung cancer BMs, directly determining the primary site based on these features remains a challenge. Thus, identifying the MRI features of different subtypes of lung cancer BMs is crucial in order to facilitate early diagnosis and treatment. This study aimed to characterize the MRI characteristics distinct to the various subtypes of lung cancer BMs in order to inform clinical decision-making.MethodsData from 1,129 patients diagnosed with lung cancer BMs (a total of 8,312 lesions) from three institutions, including clinicopathological information and MRI features, were retrospectively analyzed. Among these cases of BMs, 369 (2,780 lesions) originated from small-cell lung cancer (SCLC) and 760 (5,532 lesions) from non-small cell lung cancer (NSCLC). Among the patients with NSCLC, there were 689 cases (5,243 lesions) of adenocarcinoma (AD) and 71 cases (289 lesions) of squamous cell carcinoma (SCC). Regarding epidermal growth factor receptor (EGFR) status, there were 188 wild-type cases (1,257 lesions) and 344 mutant-type cases (2,880 lesions). This study was divided into three parts. For Part I (comparison between SCLC and NSCLC), Part II (comparison between AD and SCC), and Part III (comparison between EGFR wild type and mutant type), a stepwise in-depth analysis was performed—from the level of pathological classification to the level of gene mutation status—of the clinical characteristics of patients with lung cancer BMs and of the quantity, size, location, and signal characteristics of BMs lesions based on brain MRI. According to different signal combinations of DWI and CE-T1WI, the BMs lesions were divided into seven patterns, namely Pattern I–VII: Pattern I: DWI-negative + CE-T1WI-positive; Pattern II: DWI-negative + CE-T1WI ring; Pattern III: DWI-positive + CE-T1WI-positive; Pattern IV: DWI ring + CE-T1WI-positive; Pattern V: DWI-positive + CE-T1WI ring; Pattern VI: DWI ring + CE-T1WI ring; Pattern VII: DWI-positive + CE-T1WI-negative. “Positive” indicates homogeneous hyperintensity on DWI or CE-T1WI, while “negative” indicates hypointensity or isointensity on DWI or CE-T1WI, and “ring” refers to ring enhancement.ResultsIn the Part I analysis, SCLC BMs tended to be multiple (>10 lesions; 0.5–1 cm in size), occur in the frontal/parietal lobes and periventricular regions, and have higher proportions of patterns consisting of diffusion-weighted imaging (DWI)-positive plus contrast-enhanced T1-weighted imaging (CE-T1WI) ring features, DWI ring plus CE-T1WI ring features, and DWI-positive plus C E-T1WI-negative features (all P values <0.05). NSCLC BMs had higher proportions of patterns consisting of DWI-negative plus CE-T1WI-positive features and DWI ring plus CE-T1WI-positive features (P<0.05). In the Part II analysis, as compared to AD BMs, SCC BMs have more peritumoral edema, and occur in the centrum semiovale, with higher proportions of patterns consisting of DWI ring plus CE-T1WI ring features and DWI-positive plus CE-T1WI-negative features (P<0.05). EGFR mutant-type BMs tended to be multiple (>10 lesions; <1 cm in size) and have less hemorrhage compared to wild-type BMs (P>0.05). DWI hyperintensity without CE-T1WI enhancement was more common in SCLC BMs than in NSCLC BMs (20.6% vs. 4.5%; P<0.001) and in SCC BMs than in AD BMs (33.9% vs. 2.8%; P<0.001).ConclusionsMRI and clinical features may provide the ability to noninvasively distinguish between SCLC and NSCLC and between AD and SCC, as well as to partially indicate EGFR status. DWI hyperintensity without CE-T1WI enhancement might serve as a key subtype-specific feature that could aid in clinical decision-making.

Background: The Artificial Intelligence Model (AIBx) version 1 algorithm is a web-based model for analyzing thyroid ultrasound images and detecting the probability of thyroid cancer. It has demonstrated the ability to risk-stratify thyroid nodules as benign or malignant with significant accuracy. The AIBx version 2 (v2) algorithm was created by adding more images and modifying the training techniques to advance the ability to differentiate between benign and malignant thyroid nodules along with TI-RADS descriptors. This study evaluates the new algorithm's performance on an external dataset with confirmed histopathology diagnosis. Methods: All patients aged 18 years or above who underwent surgery from 2015 to 2019 were included in this study. Thyroid nodules 1–4 cm in size and with clear margins were evaluated. Thyroid lymphomas, thyroid nodules treated with ethanol ablation, and thyroid metastasis from other cancers were excluded. A longitudinal and transverse image of a thyroid nodule was provided to the AIBx v2 algorithm, with these images matched with the database of benign and malignant thyroid nodules by the AIBx v2 algorithm to classify the given nodule as either benign or malignant. The results of the AIBx v2 algorithm were compared with confirmed histopathology diagnosis to evaluate sensitivity, specificity, and positive and negative predictive values. Results: A total of 176 nodules met the inclusion criteria. The prevalence of malignancy in the dataset was 14.2%. The negative predictive value for AIBx v2 was 98.5% (95% CI, 96–100). The sensitivity, specificity, positive predictive value, and accuracy for the model were 92% (81–100), 86% (81–92), 53.5% (39–68), and 87.5% (83–92), respectively. The area under the curve was 0.894 (84–94). The diagnostic odds ratio for AIBx was 73.32. Only 4 nodules had a diagnosis of Bethesda III and IV. In this category, AIBx had a negative predictive value of 100%. Conclusion: The negative predictive value of AIBx v2 is comparable to the Bethesda System for Reporting Thyroid Cytopathology. In this study, where data from an external institution was tested, AIBx v2 showed good sensitivity and specificity. As there were only 4 nodules in the Bethesda category III and IV, further testing is needed in this area. Overall, AIBx v2 provides rapid risk stratification, which could decrease unnecessary biopsies.

Hidradenocarcinoma (HC) is an extremely rare malignant tumor originating from skin appendages, accounting for approximately 6% of malignant sweat gland tumors and less than 0.001% of all tumors. Sweat gland carcinoma with endocrine mucin-producing sweat gland carcinoma belongs to the category of low-grade cutaneous neuroendocrine carcinoma. Due to its extremely low incidence, lack of distinct clinical manifestations, and multiple pathological features, the clinicopathological diagnosis is challenging, often leading to misdiagnosis. To date, fewer than 20 cases have been reported in the literature. Low-grade cutaneous neuroendocrine carcinoma (LGNECS) has been proposed as a novel primary skin tumor with neuroendocrine differentiation. This study presents the clinicopathological characteristics of two cases of LGNECS and conducts a literature review. In case 1, the biopsy suggested squamous cell carcinoma (SCC), and in case 2, the biopsy indicated a tumor derived from skin appendages. However, postoperative histopathological examinations in both cases diagnosed low-grade sweat gland carcinoma with neuroendocrine differentiation. LGNECS poses significant challenges to clinicopathological diagnosis. Case 1: An 86-year-old male presented with a nodular lesion on the left temporal region, which had been present for one year. The lesion, measuring 3.5 × 2.5 cm, was ulcerated with partial crusting. Biopsy initially suggested SCC. However, the postoperative diagnosis was low-grade sweat gland carcinoma with neuroendocrine differentiation. Case 2: A 74-year-old female developed red papules on the lumbosacral region three years ago, each approximately 1 cm in size, accompanied by skin ulceration. The lesion was initially not considered significant. Over time, the mass increased in size and developed a foul odor. Biopsy suggested sweat gland carcinoma, and the postoperative diagnosis confirmed low-grade sweat gland carcinoma with neuroendocrine differentiation. Both patients received no treatment after surgery and have been followed up for 4 to 16 months, with no recurrence or metastasis observed. Sweat gland carcinoma with neuroendocrine differentiation is extremely rare, and biopsy is prone to misdiagnosis. A definitive diagnosis requires a comprehensive analysis of postoperative specimens combined with immunohistochemical studies. This study reports two cases of sweat gland carcinoma with neuroendocrine differentiation, providing valuable insights for clinicians and pathologists.

Modelling of dose-escalated proton beam therapy for Locally Advanced Pancreatic Cancer using simulated phantoms.

Optimizing outcomes in laparoscopic segmental resection for bowel endometriosis.

Management of appendiceal neuroendocrine tumours (aNET) with a size of 1-2 cm is a topic of debate, with the conflict centred on the potential oncological benefits of right hemicolectomy (RHC) versus appendectomy and the impact of RHC on quality of life. A recent study suggested that RHC may not be needed for certain aNET 1-2 cm in size. A total of 1244 adult patients with aNET 1-2 cm (diagnosed 2012-2022) who underwent appendectomy or RHC were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Similarly, a total of 270 patients (diagnosed 2012-2021) were extracted from the National Cancer Registration and Analysis Service (NCRAS) database. Kaplan-Meier (KM) plots for overall survival (OS) were generated with log-rank tests (LR). Univariable and multivariable Cox regression for all-cause mortality were performed. In the NCRAS cohort, 159 and 111 patients underwent appendectomy and RHC, respectively. The median age was 41 and 51 years for appendectomy and RHC, respectively. Most patients were female (63.7%) and of white race (86.3%). Patients who underwent RHC had a higher proportion of node-positive disease. In the SEER cohort, 957 and 287 patients underwent appendectomy and RHC, respectively. Median age was 39 and 47 years for appendectomy and RHC, respectively. Most patients were females (65.3%) and of white race (67.7%). Patients who underwent RHC had a higher proportion of node-positive disease and M1 stage. Sex and race distribution were similar for the two procedures in both NCRAS and SEER. The KM plot for OS in NCRAS (p = .061) and SEER (p = .14) showed no statistical difference between appendectomy and RHC. Cox regression for all-cause mortality showed that there is no statistical difference between appendectomy and RHC in both cohorts after adjusting for other factors, including age and N stage. Cox regression for all-cause mortality for both cohorts combined showed the same result. Survival of appendectomy is non-inferior to RHC in the management of aNET 1-2 cm, even in patients with node-positive disease. These study findings address the gap in current clinical practice guidelines.

Introduction. Cat scratch disease (CSD) is zoonotic infectious disease caused by the bacterium Bartonella henselae. Domestic cats, which are infected by fleas are the primary source of this infection. In humans, the disease occurs through contact with an infected animal, as a result of a bite or scratch. Difficulties in diagnosis are associated with the variety of clinical symptoms and lack of doctors’ alertness, especially in cases of atypical disease forms. Lymphadenopathy is the basis for differential diagnosis of CSD with neoplastic processes. The aim of the study: to focus doctors' attention on the possibility of an atypical subclinical course of CSD by analyzing a clinical case of the disease in the patient with lymphedema of the lower extremity. Materials and methods. The clinical examination results, laboratory and instrumental tests of a 35-year-old woman were analyzed. Case presentation. A 35-year-old woman consulted her family doctor with complaints of severe swelling of the left lower extremity, which had been bothering her for several months. Edema appeared in perfect health and gradually spread from the foot to the thigh.On examination, the left lower limb is swollen throughout. The diameter of the left lower leg is 4 cm larger than the right one, and the left thigh is 2.5 cm larger than the right one. In the left inguinal region, lymph nodes are visible and palpable, sensitive to palpation - 1.5-2 cm in size, dense, in the right inguinal region - up to 1 cm, not dense and not sensitive to palpation.The family doctor referred the patient to a vascular surgeon. After an ultrasound examination of the veins of the lower extremities, a complete blood count, no pathology of the veins of the lower extremities, and no other disorders were detected. The diagnosis was made: “Lymphedema of the left lower limb of unknown etiology”. The patient was referred to the regional oncology center to exclude oncological pathology. Based on the results of MRI and CT of the chest, abdominal cavity, and pelvic organs oncological pathology was excluded. Excision of the left inguinal lymph node with histopathological examination was performed, the results of which meet the histological criteria of benign lymphoreticulosis with fibrosis. When the patient was examined by an infectious diseases specialist, the doctor found out the details of the medical history: in July 2023, a domestic cat bit her foot under the left ankle joint. An enzyme-linked immunosorbent assay of blood for Bartonella henselae was prescribed and positive IgM and IgG antibodies were detected. Considering the presence of adenopathy, a cat's bite in the anamnesis, a positive serological test, and the exclusion of other causes, the diagnosis was established: Cat scratch disease, subclinical form. Lymphedema of the left lower limb, stage II-III. In addition to the vascular surgeon's recommendations – compression stockings, lymphatic drainage massage, the patient was prescribed: bicillin-5 (benzathine penicillin with procaine penicillin sterile salt) 1,500,000 units IM once every 4 weeks, for 6 months. Conclusion. Bartonella henselae infection should be considered in all cases of lymphadenitis and lymphedema of unknown etiology for timely diagnosis and antibiotic treatment at the initial stage of the cat scratch disease.