Low-grade malignant peripheral nerve sheath tumour presenting as retroperitoneal spindle cell neoplasm.

Retroperitoneal spindle cell neoplasms are diagnostically challenging. Malignant peripheral nerve sheath tumours (MPNSTs) can sometimes present as sporadic primary retroperitoneal tumours. MPNSTs are usually high-grade and highly aggressive tumours and are associated with a poor prognosis. Low-grade MPNSTs are very rarely described. This current case report describes a case of sporadic primary low-grade MPNST presenting as retroperitoneal spindle cell neoplasm. The diagnosis, imaging and immunohistopathological findings, as well as its successful surgical management, are presented.

Large retroperitoneal lymphangioma.

Abnormal cystic lymphangioma is a rare, benign tumour of lymphatic origin that often presents with subtle clinical symptoms. A man in his 20s sought medical attention for a progressively tender mass located in the right lower quadrant. Following ultrasound and CT imaging, surgical pathology confirmed the presence of abnormal cystic lymphangioma. This case is noteworthy because of the patient's young age and the retroperitoneal location. An exploratory laparotomy was performed, mitigating the risk of recurrence. In the future, if imaging identifies a cystic mass, consideration of abnormal cystic lymphangioma within the differential diagnosis is imperative. Despite its predominantly subtle symptoms and non-malignant nature, the mass effect by the abnormal cystic lymphangioma can compromise surrounding structures. Overall, clinicians confronted with a cystic mass should adopt a comprehensive diagnostic approach, encompassing abnormal cystic lymphangioma in the differential diagnosis due to its unknown and complex nature.

Ovarian tumor cell-derived JAGGED2 promotes omental metastasis through stimulating the Notch signaling pathway in the mesothelial cells.

The primary site of metastasis for epithelial ovarian cancer (EOC) is the peritoneum, and it occurs through a multistep process that begins with adhesive contacts between cancer cells and mesothelial cells. Despite evidence that Notch signaling has a role in ovarian cancer, it is unclear how exactly it contributes to ovarian cancer omental metastasis, as well as the cellular dynamics and intrinsic pathways that drive this tropism. Here we show that tumor cells produced the Notch ligand Jagged2 is a clinically and functionally critical mediator of ovarian cancer omental metastasis by activating the Notch signaling in single-layered omental mesothelial cells. In turn, Jagged2 promotes tumor growth and therapeutic resistance by stimulating IL-6 release from mesothelial cells. Additionally, Jagged2 is a potent downstream mediator of the omental metastasis cytokine TGF-ß that is released during omental destruction. Importantly, therapeutic inhibition of Jagged2-mediated omental metastasis was significantly improved by directly disrupting the Notch pathway in omental mesothelial cells. These findings highlight the key role of Jagged2 to the functional interplay between the TGF-ß and the Notch signaling pathways during the metastatic process of ovarian cancer cells to the omentum and identify the Notch signaling molecule as a precision therapeutic target for ovarian cancer metastasis.

Radical resection and hyperthermic intraperitoneal chemotherapy (HIPEC) in the treatment of high risk recurrent retroperitoneal sarcoma-A pilot study in a tertiary Asian centre.

BACKGROUND: Peritoneal sarcomatosis (PS) is a difficult entity to treat with limited options and guarded prognosis. We aimed to determine if the addition of hyperthermic intraperitoneal chemotherapy (HIPEC) could offer superior local recurrence-free survival in patients with retroperitoneal sarcoma at high risk of developing PS as opposed to extended resection alone. METHODS: This is a single arm, phase II intervention study where all patients with recurrent localized retroperitoneal sarcoma considered at high risk of developing PS were considered for enrolment (ClinicalTrials.gov identifier: NCT03792867). Upon enrolment, patients underwent vigorous preoperative testing to ensure fitness for the procedure. During surgery, patients underwent extended resection and HIPEC with doxorubicin. Patients were followed-up every 2 weeks (± 10 days) for the first month and subsequently every three months (± 1 month) up to a year post-surgery, and were assessed for potential chemotherapy toxicity and post-treatment complications. After a year from resection and HIPEC, patients were followed-up either during routine clinic review or contacted via telephone every year (± 1 month) for 3 years. RESULTS: Six patients were recruited but one patient dropped out due to adverse and unexpected intraoperative events. The remaining patients completed the procedure uneventfully. Post-HIPEC, all patients recurred with a disease-free interval ranging from six to 24 months. Three patients died due to complications from recurrent disease whereas the remaining three patients are alive as of their last visit. The overall survival at time at reporting ranged between 22 to 56 months. CONCLUSION: The procedure is feasible with no major morbidity to patients. However, we are unable to recommend for it to be implemented as a routine procedure at this current stage due to lack of improved survival outcomes. Further multi-institutional studies may be conducted to yield better results.

Deep learning radiomics-based prediction model of metachronous distant metastasis following curative resection for retroperitoneal leiomyosarcoma: a bicentric study.

BACKGROUND: Combining conventional radiomics models with deep learning features can result in superior performance in predicting the prognosis of patients with tumors; however, this approach has never been evaluated for the prediction of metachronous distant metastasis (MDM) among patients with retroperitoneal leiomyosarcoma (RLS). Thus, the purpose of this study was to develop and validate a preoperative contrast-enhanced computed tomography (CECT)-based deep learning radiomics model for predicting the occurrence of MDM in patients with RLS undergoing complete surgical resection. METHODS: A total of 179 patients who had undergone surgery for the treatment of histologically confirmed RLS were retrospectively recruited from two tertiary sarcoma centers. Semantic segmentation features derived from a convolutional neural network deep learning model as well as conventional hand-crafted radiomics features were extracted from preoperative three-phase CECT images to quantify the sarcoma phenotypes. A conventional radiomics signature (RS) and a deep learning radiomics signature (DLRS) that incorporated hand-crafted radiomics and deep learning features were developed to predict the risk of MDM. Additionally, a deep learning radiomics nomogram (DLRN) was established to evaluate the incremental prognostic significance of the DLRS in combination with clinico-radiological predictors. RESULTS: The comparison of the area under the curve (AUC) values in the external validation set, as determined by the DeLong test, demonstrated that the integrated DLRN, DLRS, and RS models all exhibited superior predictive performance compared with that of the clinical model (AUC 0.786 [95% confidence interval 0.649-0.923] vs. 0.822 [0.692-0.952] vs. 0.733 [0.573-0.892] vs. 0.511 [0.359-0.662]; both P < 0.05). The decision curve analyses graphically indicated that utilizing the DLRN for risk stratification provided greater net benefits than those achieved using the DLRS, RS and clinical models. Good alignment with the calibration curve indicated that the DLRN also exhibited good performance. CONCLUSIONS: The novel CECT-based DLRN developed in this study demonstrated promising performance in the preoperative prediction of the risk of MDM following curative resection in patients with RLS. The DLRN, which outperformed the other three models, could provide valuable information for predicting surgical efficacy and tailoring individualized treatment plans in this patient population. TRIAL REGISTRATION: Not applicable.

A retrospective clinical analysis of 11 cases of PEComa from different sites.

PURPOSE: The objective of this paper is to offer a thorough examination of the clinical presentations, etiology, and treatment strategies associated with perivascular epithelioid cell tumors (PEComas). METHODS: This retrospective study examined the comprehensive archival data of PEComa cases diagnosed at Beijing Hospital from 2015 to 2023. The pathology slides of all patients were thoroughly reassessed by two experienced pathologists. A thorough retrospective analysis was undertaken, incorporating clinicopathological data including gender, age at diagnosis, initial clinical manifestations, signs, disease onset site, tumor markers, imaging findings, therapeutic modalities, pathological features, immunohistochemical profiles, treatment responses, and prognostic indicators. Patients were evaluated for disease severity according to established pathological classification criteria and were followed up until the designated analysis cut-off date. In instances where patients were unable to be monitored on-site, they were contacted via telephone for postoperative follow-up inquiries. RESULTS: This study included 11 patients with ages ranging from 17 to 66 years old, presenting with the disease in multiple anatomical sites, including the retroperitoneum (2/11), liver (4/11), kidney (4/11), lung (1/11), and broad ligament of the uterus (1/11). Most patients presented with non-specific clinical symptoms and were subsequently diagnosed with space-occupying lesions upon physical examination. The tumor demonstrated progressive growth and enlargement, which could result in compression of neighboring organs. Preoperative imaging alone is insufficient for a definitive diagnosis of PEComa, but MRI can provide an initial evaluation of the tumor's potential malignancy. Molecular marker testing specific to PEComa, such as HMB-45 (90.0%), SMA (81.8%), Melan-A (90.9%), vimentin (90.9%), and Desmin (36.3%), was conducted on all patients. No adjuvant therapies were administered postoperatively. Upon analysis, no instances of relapse at the primary site or the development of new tumors at other sites were observed. Regular imaging reviews of three patients with malignant PEComa post-surgery showed no evidence of recurrence. CONCLUSIONS: The clinical presentation, tumor biomarkers, and imaging characteristics of PEComa lack specificity, necessitating dependence on pathology and immunohistochemistry for precise diagnosis. The mainstay of treatment consists of surgical resection, with patients typically experiencing a favorable prognosis.

Intraoperative radiofrequency ablation for unresectable abdominal paraganglioma: a case report.

For pheochromocytoma and paraganglioma (PPGL), the efficacy of percutaneous ablative therapies in achieving control of metastatic tumors measuring <3 cm had been demonstrated in only few reports, and intraoperative radiofrequency ablation (RFA) of locally invasive primary PPGLs has not been reported. We presented the case of a 31-year-old man who had a 9-cm functioning unresectable PPGL. He was treated with 13 cycles of cytotoxic chemotherapy without objective tumor response, according to the Response Evaluation Criteria in Solid Tumors (RECIST). Subsequently, magnetic resonance imaging revealed a 9.0 × 8.6 × 6.0-cm retroperitoneal mass that extended to the inferior portion of the inferior vena cava, the inferior mesenteric artery, and the infrarenal aorta. Biochemical evaluation demonstrated high level of plasma normetanephrine (20.2 nmol/L, normal range <0.9 nmol/L). Genetic investigation showed the germline pathogenic variant c.1591delC (p. Ser198Alafs*22) in the SDHB gene. I131-metaiodobenzylguanidine scintigraphy was negative and Ga68-dotatate PET-CT scan showed high tumor uptake without distant metastases. On open laparotomy, tumor debulking was not possible. Therefore, intraoperative RFA was performed by a highly experienced team of interventional radiologists. At 12 months after the RFA, the tumor volume decreased from 208 to 45 mL (78%), plasma normetanephrine decreased from 20.2 to 2.6 nmol/L (87%), and the doxazosin dose was reduced from 16 to 8 mg/day. To our best knowledge, this was the first report on intraoperative RFA that markedly reduced the size of a large primary unresectable PPGL, along with clinical and biochemical responses.

Cytological Features of Fibrin-associated Diffuse Large B-cell Lymphoma Arising in Retroperitoneal Pseudocyst: The First Case Report.

BACKGROUND/AIM: Fibrin-associated diffuse large B-cell lymphoma (FA-DLBCL) is frequently associated with the Epstein-Barr virus (EBV) and manifests as non-mass-forming microscopic lesions within fibrin-rich lesions. Herein, we describe the cytological features of FA-DLBCL. CASE REPORT: A 72-year-old man presented with a large retroperitoneal cystic mass that was treated by cyst aspiration and laparoscopic excision. Individually dispersed large, atypical cells in a necrotic background contained scant cytoplasm and hyperchromatic nuclei with irregular nuclear contours, frequent karyorrhectic debris, and mitotic figures. A fibrinous exudate with necrotic material attached to the inner surface of the cystic mass contained large, atypical cells that were individually scattered or arranged in small clusters. These were positive for cluster of differentiation 20 and Epstein-Barr virus-encoded RNA in situ hybridization. CONCLUSION: We cytologically characterized FA-DLBCL as large, atypical cells that were individually scattered or arranged in small clusters in a necrotic background. To the best of our knowledge, we revealed the cytological features of FA-DLBCL.

Diagnosis and treatment of malignant retroperitoneal mesothelioma: A case report.

RATIONALE: Malignant peritoneal mesothelioma (MPM) is a rare clinical disease. Although there are several reports describing intraperitoneal mesothelioma of the lung, liver, and intestine, retroperitoneal mesothelioma is, to our knowledge, very rare and rarely reported. In recent years, our best clinical protocols for the treatment and diagnosis of retroperitoneal mesothelioma have not been proven and the diagnosis and treatment are challenging. PATIENT CONCERNS: A 37-year-old Chinese woman complained of bilateral low back pain for a month, with obvious symptoms of low back pain on the left side. To treat low back pain, retroperitoneal masses were found during physical examination. The patient consulted a urological specialist for further treatment. DIAGNOSIS: After the operation, pathological biopsy confirmed retroperitoneal epithelioid diffuse mesothelioma. INTERVENTIONS: After exclusion of surgical contraindications, the patient underwent laparoscopic retroperitoneal lesion resection under tracheal intubation and general anesthesia, and the operation was successful. OUTCOMES: On the tenth day after surgery, the patient vital signs were stable, and he was discharged. LESSONS: Patients with malignant peritoneal mesothelioma may have no typical clinical symptoms, and the diagnosis is based on pathological and immunohistochemical examination. In selected patients, surgical cell reduction and intraoperative intraperitoneal heat chemotherapy have become the first choice of treatment, which can achieve ideal therapeutic effects and prolong survival.

What is the association of preoperative biopsy with recurrence and survival in retroperitoneal sarcoma? A systematic review by the Australia and New Zealand Sarcoma Association clinical practice guidelines working party.

Preoperative biopsy for retroperitoneal sarcoma (RPS) enables appropriate multidisciplinary treatment planning. A systematic review of literature from 1990 to June 2022 was conducted using the population, intervention, comparison and outcome model to evaluate the local recurrence and overall survival of preoperative biopsy compared to those that had not. Of 3192 studies screened, five retrospective cohort studies were identified. Three reported on biopsy needle tract seeding, with only one study reporting biopsy site recurrence of 2 %. Two found no significant difference in local recurrence and one found higher 5-year local recurrence rates in those who had not been biopsied. Three studies reported overall survival, including one with propensity matching, did not show a difference in overall survival. In conclusion, preoperative core needle biopsy of RPS is not associated with increased local recurrence or adverse survival outcomes.

Astrocitoma de bajo grado en un teratoma retroperitoneal: reporte de caso / Low-grade astrocytoma within a retroperitoneal teratoma: Case report

Los teratomas son neoplasias que se originan de las células germinales, algunos pueden sufrir una transformación maligna. La Organización Mundial de la Salud (OMS) los clasificó como teratomas con malignidad de tipo somático, los cuales son poco comunes, siendo los sarcomas el tipo histológico con mayor incidencia. Es importante diferenciar esté tipo de tumores ya que influye en el pronóstico y en la supervivencia del paciente. A continuación se presenta el caso de un masculino de 5 meses de edad, que inició su padecimiento al mes de vida con la presencia de estreñimiento y aumento del perímetro abdominal, los estudios de imagen revelaron una lesión abdominal. Se inició tratamiento con quimioterapia y se realizó tumorectomía retroperitoneal. El reporte histopatológico reportó teratoma inmaduro grado I con foco de tejido nervioso que muestra características de astrocitoma de bajo grado. (AU)

Teratomas are neoplasms originate from germ cells and can undergo malignant transformation, the World Health Organization (WHO) classified them as teratoma with somatic-type malignancy which is uncommon and sarcomas are the histological type with the highest incidence. It is important to identify this type of tumors because influences the prognosis and survival of the patient. We present the case of a 5-month-old male, who began his condition at one month-old with constipation and increase of the abdominal circumference, imaging studies revealed an abdominal lesion, he was treated with chemotherapy and surgery. The histopathological report was immature teratoma, grade 1, with a focus of nervous tissue showing characteristics of low-grade astrocytoma. (AU)

Astrocitoma de bajo grado en un teratoma retroperitoneal: reporte de caso / Low-grade astrocytoma within a retroperitoneal teratoma: Case report

Los teratomas son neoplasias que se originan de las células germinales, algunos pueden sufrir una transformación maligna. La Organización Mundial de la Salud (OMS) los clasificó como teratomas con malignidad de tipo somático, los cuales son poco comunes, siendo los sarcomas el tipo histológico con mayor incidencia. Es importante diferenciar esté tipo de tumores ya que influye en el pronóstico y en la supervivencia del paciente. A continuación se presenta el caso de un masculino de 5 meses de edad, que inició su padecimiento al mes de vida con la presencia de estreñimiento y aumento del perímetro abdominal, los estudios de imagen revelaron una lesión abdominal. Se inició tratamiento con quimioterapia y se realizó tumorectomía retroperitoneal. El reporte histopatológico reportó teratoma inmaduro grado I con foco de tejido nervioso que muestra características de astrocitoma de bajo grado. (AU)

Teratomas are neoplasms originate from germ cells and can undergo malignant transformation, the World Health Organization (WHO) classified them as teratoma with somatic-type malignancy which is uncommon and sarcomas are the histological type with the highest incidence. It is important to identify this type of tumors because influences the prognosis and survival of the patient. We present the case of a 5-month-old male, who began his condition at one month-old with constipation and increase of the abdominal circumference, imaging studies revealed an abdominal lesion, he was treated with chemotherapy and surgery. The histopathological report was immature teratoma, grade 1, with a focus of nervous tissue showing characteristics of low-grade astrocytoma. (AU)

Radiation therapy for retroperitoneal sarcoma: practice patterns in North America.

BACKGROUND: The addition of radiation therapy (RT) to surgery in retroperitoneal sarcoma (RPS) remains controversial. We examined practice patterns in the use of RT for patients with RPS over time in a large, national cohort. METHODS: Patients in the National Cancer Database (2004-2017) who underwent resection of RPS were included. Trends over time for proportions were calculated using contingency tables with Cochran-Armitage Trend test. RESULTS: Of 7,485 patients who underwent resection, 1,821 (24.3%) received RT (adjuvant: 59.9%, neoadjuvant: 40.1%). The use of RT decreased annually by < 1% (p = 0.0178). There was an average annual increase of neoadjuvant RT by 13% compared to an average annual decrease of adjuvant RT by 6% (p < 0.0001). Treatment at high-volume centers (OR 14.795, p < 0.0001) and tumor > 10 cm (OR 2.009, p = 0.001) were associated with neoadjuvant RT. In contrast liposarcomas (OR 0.574, p = 0.001) were associated with adjuvant RT. There was no statistically significant difference in overall survival between patients treated with surgery alone versus surgery and RT (p = 0.07). CONCLUSION: In the United States, the use of RT for RPS has decreased over time, with a shift towards neoadjuvant RT. However, a large percentage of patients are still receiving adjuvant RT and this mostly occurs at low-volume hospitals.

Progress in Retroperitoneal Sarcoma Management: Surgical and Radiotherapy Approaches.

Surgical resection is the cornerstone of curative treatment for retroperitoneal sarcomas (RPS), aiming for complete excision, yet the complexity of RPS with its proximity to vital structures continues to lead to high local recurrence rates after surgery alone. Thus, the role of radiotherapy (RT) continues to be refined to improve local control, which remains an important goal to prevent RPS recurrence. The recently completed global randomized trial to evaluate the role of surgery with and without preoperative RT - STRASS1, did not demonstrate a significant overall benefit for neoadjuvant RT based on the pre-specified definition of abdominal recurrence-free survival, however, sensitivity analysis using a standard definition of local recurrence and analysis of outcomes by compliance to the RT protocol suggests histology-specific benefit in well- and some de-differentiated liposarcomas. Ultimately, multidisciplinary collaboration and personalized approaches that consider histological sarcoma types and patient-specific factors are imperative for optimizing the therapeutic strategy in the management of RPS.

Recurrence of locally invasive retroperitoneal dedifferentiated liposarcoma shortly after surgery: A case report and literature review.

RATIONALE: Retroperitoneal dedifferentiated liposarcoma (RPDDL) is an uncommon malignancy, which often remains undetected for many years due to having adequate space in the retroperitoneal cavity and lacking clinical manifestations in the early stage of the disease. Surgical procedure is usually used as the first choice for treatment. However, it is prone to local recurrence after the operation, resulting in an unfavorable prognosis. Our aim is to draw useful lessons from the new case and provide some experience for management of the disease. PATIENT CONCERNS: We describe a 55-year-old male patient who was admitted for a 3-week history of persistent dull ache of the left waist. A large mass of the left upper abdomen was palpated in physical examination. Moreover, the imaging examination revealed that the diameter of the mass was about 21 cm, and some adjacent vital organs were invaded, which brought great challenges to complete surgical resection. DIAGNOSIS: The postoperative pathological results confirmed that the mass was RPDDL with invasion of the surrounding vital structures including pancreas, spleen, left adrenal gland, left kidney, and vasculature with tumor emboli. INTERVENTIONS: Surgical resection of the mass was performed by our multidisciplinary team. The patient received chemotherapy 1 month after surgery. OUTCOMES: The effect of chemotherapy seemed to be unsatisfactory. Local multifocal recurrence of the tumor was considered about 2 months after surgery. Finally, he gave up any treatments and died of the disease. LESSONS: Regular physical examination and ultrasound screening may detect the disease as early as possible, especially for high-risk group aged 60 to 70, which should be popularized. Incomplete resection, vascular invasion, and interruption of postoperative treatment may lead to an unfavorable prognosis. Therefore, we think that patients with the disease may benefit from complete surgical resection and uninterrupted adjuvant therapy.

[Advances in the etiology of retroperitoneal liposarcoma].

Retroperitoneal liposarcoma is the most common retroperitoneal soft tissue tumor with insidious onset, difficulty in treatment, and easy recurrence. Different subtypes of retroperitoneal liposarcoma differ significantly in pathogenic mechanism, biological behavior, and prognosis. The characteristic molecular event of well-differentiated and dedifferentiated liposarcoma is the amplification of the long arm segment of chromosome 12. The genome of myxoid liposarcoma is characterized by translocations of chromosomes 12 and 16 to form fusion genes. The genomic changes of pleomorphic and myxoid pleomorphic liposarcoma are complex, with multiple chromosomal structural abnormalities. Several signaling pathways related to adipocyte differentiation or lipid metabolism have been found to be involved in the initiation and progression of retroperitoneal liposarcoma. It is unclear whether retroperitoneal liposarcoma originates from naive preadipocytes or dedifferentiated mature adipocytes, and its metabolic characteristics are also poorly understood. The first-line drug treatment for retroperitoneal liposarcoma is anthracycline-based chemotherapy, but patients receive little benefit. Therefore, it is urgent to strengthen the basic research on retroperitoneal liposarcoma to find effective therapeutic targets.

Functional vagal paraganglioma developing 15 years after resection of a retroperitoneal paraganglioma.

The patient, a 40-year-old woman, was diagnosed as having a functional right vagal paraganglioma (PGL) 15 years after undergoing resection for a retroperitoneal PGL. 123I-MIBG scintigraphy showed no accumulation, but as the blood noradrenaline and urinary normetanephrine concentrations were elevated, the tumor was judged as being functional, and surgery was scheduled. The patient was started on doxazosin infusion and embolization of the tumor feeding vessel was performed before the surgery. Intraoperative examination showed that the tumor was contiguous with the vagal nerve, necessitating combined resection of the vagal nerve with the tumor. Postoperatively, the catecholamine levels returned to normal range. Histopathologically, the tumor was diagnosed as a moderately differentiated, intermediate-malignant-grade PGL, with a GAPP score of 4 to 6. No non-chromaffin tissue was observed in the tumor background, so that the functional vagal PGL was considered as a sporadic metachronous tumor rather than as a metastasis from the retroperitoneal PGL. More than half of head and neck paragangliomas (HNPGLs) are reported to arise in the carotid body, and about 5% from the vagal nerve. In addition, HNPGLs rarely produce catecholamines. Herein, we consider the relationship with the previously resected retroperitoneal PGL based on a review of the literature.