Retroperitoneal Tumor Research Articles

Analysis of Benign Retroperitoneal Schwannomas: A Single-center Experience.

Retroperitoneal schwannomas are rare. The purpose of this study was to present our experience with the diagnosis and treatment of 67 such tumors. We retrospectively analyzed 67 patients with retroperitoneal schwannoma admitted to the Peking University International Hospital from 2015 to 2021. Thirty-seven of the 67 patients had no obvious clinical symptoms. Complete excision was obtained in 62 and subtotal excision in 5 cases. In7 cases, tumor resection was combined with organ resection. The intraoperative blood loss was 300 ml (20-9,000 ml), the maximum size of the tumor was 9 cm (2.5-26 cm), and postoperative complication occurred in six cases (9.0%). Compared with abdominal retroperitoneal tumors, pelvic retroperitoneal tumors had larger tumor volume, more bleeding, higher proportion of block resection, and longer postoperative hospitalization time (p < 0.05). The residual mass progressed slowly in five patients with subtotal resection, and no obvious malignant transformation occurred. Complete resection of a retroperitoneal schwannoma can achieve a good long-term prognosis. Residual tumor after surgery progresses slowly and rarely become malignant. We recommend early resection after the discovery of a pelvic retroperitoneal schwannoma.

Surgical Challenges and Outcomes in Management of Benign Retroperitoneal Germ Cell Tumors—A Tertiary Care Centre Experience

Surgical Challenges and Outcomes in Management of Benign Retroperitoneal Germ Cell Tumors—A Tertiary Care Centre Experience

Comprehensive neurosurgical and visceral surgical therapy of retroperitoneal nerve tumors: a descriptive and retrospective analysis.

Nerve tumors in the retroperitoneal space are a rarity. Radical surgery according to soft tissue tumors can lead to persistent pain and neurological deficits. This study aims to evaluate clinical outcomes of patients treated by a visceral- / neurosurgical approach. 33 patients with a retroperitoneal nerve tumor underwent surgery between 01/2002 and 12/2022 at our department. A visceral surgeon provided access to the retroperitoneal space, followed by micro-neurosurgical tumor preparation under neuromonitoring. Clinical examination and MRI were performed 12 weeks after surgery and further 3 months (WHO grade > 1) or 12 months (WHO grade 1). Further examinations were based on MRI findings and residual symptoms with median follow-up time of 24 months. One patient was treated for two distinct masses resulting in a total of 34 histological findings. Schwannomas (n = 15; 44.1%) and neurofibromas (n = 10; 29.4%) were the most common tumors. Long-term improvements were noted in radicular pain (15/18 patients; 83.3%), motor deficits (7/16 patients; 43.8%), abdominal discomfort and pain (5/7 patients; 71.4%). Recurrences were observed in 3/33 (9,1%) patients. This study represents the largest series of retroperitoneal BPNSTs treated with microsurgical techniques. Prospective multicenter studies are warranted to establish standardized treatment guidelines.

Rare huge bilateral adrenal myelolipoma confused with retroperitoneal liposarcoma

IntroductionAdrenal myelolipomas are uncommon benign adrenal tumors, which mostly occur unilaterally. We describe a rare case of giant bilateral adrenal myelolipoma mistaken for retroperitoneal liposarcoma.Case presentationA 49‐year‐old man developed fever, left flank pain, and a large mass in his left abdomen. Plain computed tomography showed a 23‐cm mass with fat‐containing components in the retroperitoneal cavity, suggestive of retroperitoneal liposarcoma. A similar 9‐cm mass was observed in the right adrenal gland, suggesting adrenal metastasis. With a clinical diagnosis of retroperitoneal liposarcoma, we administered preoperative radiation therapy and performed a bilateral tumor resection. On postoperative day 9, a surgical site infection occurred, necessitating incisional drainage and the administration of intravenous antibiotics. The histopathological diagnosis was bilateral myelolipoma of the adrenal glands.ConclusionIn cases of bilateral retroperitoneal tumors with a large fat component, adrenal myelolipoma should be considered in the differential diagnosis to avoid overtreatment.

12315 Unveiling A Paraganglioma: Catecholamine-Induced Hyperglycemia Masquerading As Type 2 Diabetes Mellitus

Abstract Disclosure: S. Salman: None. M. Hussine: None. J. Tibaldi: None. Background: Excessive catecholamines have been demonstrated to exert adverse effects on insulin homeostasis and carbohydrate metabolism, potentially resulting in the onset of secondary DM. We present a case of a patient who had been previously misdiagnosed with T2DM for an extended period. Clinical Case: A 34-year-old woman with history of T2DM, HTN, and chronic tachycardia on beta blockers, presented with complaints of palpitations, headaches, and abdominal pain for two weeks. Upon admission, she was found to be in DKA, necessitating transient administration of insulin drip. Furthermore, she exhibited persistent tachycardia and intermittent episodes of hypertensive urgency. Notably, thyroid levels revealed euthyroidism. Although DKA resolved, her fasting blood sugar levels remained elevated and refractory to escalating insulin therapy. CT abdomen with contrast revealed a large enhancing mass in the RUQ. MRI abdomen confirmed an 8.1 cm heterogeneously enhancing T2 hyperintense mass located in the RUQ, abutting the right hepatic lobe, right adrenal gland, extrahepatic biliary ducts, and adjacent vessels. Given suspicions of a neuroendocrine tumor, she was transferred to the surgical service for tumor excision. Hormonal analysis revealed elevations in plasma metanephrines (620 pg/mL, n 0-88 pg/mL), plasma normetanephrines (9954 pg/mL, n 0-210.1 pg/mL), 24-hr urine normetanephrines (10,952 μg/24hr, n 110-720 μg/24hr) and 24-hr urine metanephrines (1406 μg/24hr, n 35-278 μg/24hr). Additionally, she exhibited elevated 24-hr urine epinephrine fraction (218 μg/g Cr, 0-20 μg/g Cr) and 24-hr urine norepinephrine fraction (2775 μg/g Cr, 0-45 μg/g Cr). Preoperatively, appropriate alpha and beta blockade were administered, followed by successful retroperitoneal tumor resection. Postoperatively, her glucose levels normalized without the need for further insulin therapy, and no episodes of hypoglycemia were reported. Histopathological examination of the excised mass revealed an 11 cm sympathetic paraganglioma with retention of SDHB staining. Genetic testing for SDHB, SDHD, VHL, and RET mutations is pending. Conclusion: This case underscores the potential oversight of pheochromocytomas and paragangliomas due to their nonspecific symptomatology, often mimicking more prevalent conditions, thereby presenting diagnostic challenges. The catecholamines secreted by these tumors can lead to both impaired insulin secretion and increased insulin resistance, resulting in clinically significant manifestations. The exact mechanism underlying the glycemic dysregulation remains controversial, necessitating further investigation through large-scale multicenter prospective studies to enhance understanding and inform diagnostic and therapeutic strategies for these tumors, which can manifest with severe and potentially fatal glycemic disturbances. Presentation: 6/1/2024

A rare well-differentiated renal retroperitoneal liposarcoma: a case report

Introduction and importance: Retroperitoneal liposarcomas (RPLPSs) are rare tumors that arise from mesenchymal cells in the peritoneum cavity. The sites of PRLPSs vary a lot, but renal PRLPSs are extremely rare (there are only 45 cases of Renal retroperitoneal liposarcomas on PubMed). In this case, the authors present a rare renal retroperitoneal liposarcoma case, describe the major concepts, and raise awareness about this rare tumor. Case presentation: A 44-year-old woman presented to the clinic with hirsutism and irregular menstruation; upon physical examination, a large abdominal mass was accidentally identified; the patient had Doppler ultrasound (Doppler US) and MRI, which both showed a mass arising from the right upper pole of the kidney, fine needle aspiration (FNA) confirmed the diagnosis of retroperitoneal liposarcoma, patient underwent surgical removal and her symptoms disappeared. Clinical discussion: The retroperitoneum is a cavity behind the abdominal wall containing organs like the pancreas and kidneys. Retroperitoneal tumors (RPTs) are rare neoplasms, primarily of mesenchymal origin. Retroperitoneal liposarcomas (RPLPS) are the most common RPT, often asymptomatic until large, and rarely metastasize but frequently recur. Liposarcomas are classified into five subtypes, with well-differentiated liposarcoma being the most common and characterized by high local recurrence. The presence of specific oncologic mutations affects the prognosis and the response to treatment. Conclusion: In rare cases, retroperitoneal liposarcomas can arise from sites near the kidney and compress the adjoining adrenal gland.

Hyper-realistic rendering-assisted laparoscopic adrenalectomy for giant adrenal tumors: a pilot study.

This study aimed to explore the application value of hyperrealistic rendering (HRR) in laparoscopic giant adrenal tumor resection. We retrospectively analyzed 25 patients with giant adrenal tumors from January 2021 to January 2024, with a median age of 56 (40.5, 58.5) years and a tumor median diameter of 7.20 (6.80, 8.50) cm. All patients underwent preoperative medical HRR based on enhanced computed tomography, followed by laparoscopic adrenal tumor resection. HRR was used to initially determine the nature of the tumor and develop a detailed surgical plan, which was completed in 25 patients preoperatively. All 24 cases of tumors were located in the adrenal gland, 1 case was located in the retroperitoneum, and 13 and 12 cases were on the left and right side, respectively. Preoperative HRR 3D imaging was consistent with the intraoperative situation, and 25 cases had successful surgeries. The median operation time was 165 (120.0, 250.0) min, and median bleeding and blood transfusion volume were 200 (150.0, 450.0) and 200.0 (150.0, 450.0) mL, respectively. There were no collateral injuries to important organs and major vessels and no cases of conversion to open surgery. For large retroperitoneal adrenal tumors, HRR for three-dimensional (3D) reconstruction imaging enables the operator to fully understand the relationship between the tumor and surrounding organs and blood vessels preoperatively, which can reduce intraoperative bleeding and collateral injuries, improve the success rate of laparoscopic resection, and safety of the operation.

A case of chronic contained rupture of abdominal aortic aneurysm mimicking a retroperitoneal tumor.

Chronic contained rupture of abdominal aortic aneurysm (CCR-AAA) is a rare subtype of abdominal aortic rupturethat can mimic other retroperitoneal lesions. We report a case of CCR-AAA in a man in his sixties who presented witha 10-month history of right low back pain and weight loss. Contrast-enhanced computed tomography (CT) revealed alobulated retroperitoneal mass around the abdominal aorta, initially misdiagnosed as a possible hemorrhagicretroperitoneal tumor. Despite multiple imaging studies including CT, magnetic resonance imaging (MRI), and 18F-fluorodeoxyglucosepositron emission tomography (FDG-PET)/CT, as well as a CT-guided biopsy, the correct diagnosisremained elusive for 34 months. Key findings included subtle aortic wall irregularity on CT, high signal intensity onT1-weighted MRI suggesting hematoma, peripheral FDG uptake on PET/CT, and histological findings of biopsy tissueconsistent with organizing hematoma. Surgery confirmed the diagnosis, revealing an organized hematoma with adefect in the right wall of the abdominal aortic aneurysm. This case demonstrates that CCR-AAA can present withatypical radiological features, potentially leading to misdiagnosis. When encountering a para-aortic mass with ahemorrhagic component, careful observation of the AAA morphology and aortic wall contour is crucial for anaccurate diagnosis of CCR-AAA.

Retroperitoneal Functional Paraganglioma: A Case Report and Review of the Literature

Retroperitoneal paragangliomas are rare neuroendocrine tumors. They are defined as extra-adrenal chromaffin tumors and account for around 1/5th of all chromaffin tumors. They are often asymptomatic and can reach significant dimensions. We report the case of a 52-year-old female patient who presented with abdominal pain. Thoraco-abdomino-pelvic computed tomography (TAP CT) showed a right retroperitoneal tumor, urinary methoxylates were elevated. After adequate pharmacological preparation, the patient underwent surgery without complications. Blood pressure and urinary catecholamines were normal after surgery.

Laparoscopic excision in patient with retroperitoneal schwannoma: A case report

Schwannomas are rare benign tumours that develop on the cranial or spinal nerves. They are often asymptomatic and discovered by chance following pelvic pain. MRI provides a positive diagnosis of the tumour, showing T1 hyposignal, T2 hypersignal, and heterogeneous contrast enhancement. An angioscanner and a uroscanner in the preoperative phase are useful to assess the relationship with neighbouring structures.The ideal treatment for schwannomas is complete excision with negative margins, even if it requires the sacrifice of neighbouring organs, given the risk of malignancy and the possibility of recurrence.We present a case of a retroperitoneal schwannoma located at the L5-S1 space, diagnosed by MRI following pelvic pain. The treatment involved a laparoscopic transabdominal excision, with a normal postoperative follow-up.The aim of this case report is to aid different medical teams in the management of schwannomas and to highlight the advantages of the laparoscopic anterior approach for retroperitoneal tumours compared with laparotomy.

P001 AN UNCOMMON CAUSE OF HIGH BLOOD PRESSURE IN YOUNG BASKETBALL PLAYER

Paragangliomas are rare neuroendocrine tumors that affect approximately 1.5–9 patients per million. They originate from chromaffin cells of the adrenal medulla or sympathetic and parasympathetic ganglia. Paragangliomas account for 10%–20% of retroperitoneal tumors and can manifest at any age. These tumors can secrete catecholamines, leading to symptoms such as hypertension, headaches, and diaphoresis.However, palpitations or tachycardia may also be present. Definitive treatment entails surgical resection, with acceptable rates of morbidity and mortality, necessitating careful patient preparation and intraoperative management. Case Presentation: We present the case of a 29-year-old man with a BMI 26,5 kg/m2, who is physically active and without other cardiovascular risk factors, episodic hypertension, headaches and blush. A contrast CT scan of the abdomen revealed a retroperitoneal intercavoaortic mass and 24-hour urine Normetanephrines were significantly elevated, indicating a functional paraganglioma. Laboratory tests revealed an elevated plasma normetanephrine level of 1838 pg/ml (reference values 0 - 180 pg/ml). The patient was prepared for surgery with alpha blockers, followed by beta blockers. Intraoperative blood pressure elevation was managed with intravenous beta blockers. Postoperatively, the patient did not require anti-hypertensives. The tumor, measuring 6x4x3.5 cm, histopathology and immunohistochemistry confirmed the diagnosis of a normetanephrine producing paraganglioma. The genetic study revealed a pathogenic variant in the SDHB gene, specifically the c.166_170delCCTCA (p.Pro56Tyrfs*5) in heterozygosity. This variant is associated with a 49% risk of Pheochromocytoma and Hereditary Paraganglioma, a 14% risk of Renal Carcinoma and susceptibility to Gastrointestinal Stromal Tumors. The c.166_170delCCTCA variant follows an autosomal dominant inheritance pattern, indicating a 50% risk of recurrence. Conclusions: The diagnosis of extra-adrenal retroperitoneal paragangliomas remains challenging due to the silent evolution of the condition. It is essential to consider screening patients who are young, and present with resistant arterial hypertension for secondary hypertension.

Imaging in Primary Retroperitoneal Tumors

Imaging in Primary Retroperitoneal Tumors

Primary Retroperitoneal DOG-1 Positive &amp; P16 Negative Squamous Cell Carcinoma in a Male – A Rare Case Report

Retroperitoneal neoplasms represent a rare subset of tumors, accounting for only 0.1–0.2% of all cancers. Among them, squamous cell carcinoma (SCC) arising in the retroperitoneal cavity is exceedingly rare, with limited understanding of its pathogenesis and clinical features. Here, a case of primary retroperitoneal squamous cell carcinoma is reported in a male patient who presented with complains of abdominal pain and recurrent diarrhea. On radiological imaging, a large, heteroechoic mass with necrotic components enveloping the celiac trunk in the retroperitoneal region was noted. Histopathological assessment of a core biopsy confirmed a malignant tumor with large atypical cells in clusters with moderate to marked nuclear pleomorphism, prominent nucleoli and abundant eosinophilic to clear cytoplasm. An immunohistochemical (IHC) panel, including markers such as Epithelial Membranous Antigen (EMA), PanCK, CK7, CK20, DOG-1, CD117, β-Catenin, SOX10, CD10, SMA, S100, CEA, TTF-1, CDX2, HMB45, p16, p53, p40 and p63 was systematically conducted for further characterization. Based on the Immunohistochemical (IHC) results, a myriad of differentials were ruled out and the diagnosis of primary retroperitoneal squamous cell carcinoma with DOG1 positivity and P16 negativity was established. Based on extensive research conducted on PubMed, Scopus, and Google Scholar, it appears that this case could potentially be the first documented instance of a male patient with primary retroperitoneal squamous cell carcinoma exhibiting positive DOG1 and negative p16.

Retroperitoneal infantile hemangioma: a case report and literature review

BackgroundRetroperitoneal infantile hemangioma (RIH), a type of primary retroperitoneal tumors, are exceptionally rare in clinical practice. Infantile hemangiomas typically manifest on the skin’s surface. RIHs are exceptionally rare and typically small. In adults, these tumors often manifest without specific clinical symptoms or detectable signs for a definitive diagnosis. This case report details a patient diagnosed with RIH. We recommend complete excision of the tumor after a comprehensive evaluation, followed by postoperative pathology, to achieve a conclusive diagnosis. We believe that managing critical retroperitoneal structures and vessels intraoperatively presents a significant challenge for all procedures involving primary retroperitoneal tumors.Case summaryA 47-year-old male was diagnosed with gallstones and underwent surgery 3 months ago at other institution for unexplained nausea and vomiting. Follow-up imaging 2 months after surgery revealed a retroperitoneal mass below the left renal pole. Upon presentation to our hospital, the patient continued to experience intermittent nausea and vomiting, with no other significant symptoms or signs. Considering the patient’s 8-year history of hypertension, a paraganglioma was initially suspected. We performed the laparoscopic mass resection after a detailed assessment. However, postoperative pathology revealed it a capillary hemangioma (old term)/infantile hemangioma.ConclusionRIHs are exceedingly rare benign tumor. The possibility of malignancy should be ruled out, and surgical resection is recommended following a thorough evaluation, with the diagnosis confirmed through pathological examination.

Laparoscopic resection for retroperitoneum ganglioneuroma with Supine hypotension syndrome

BackgroundSupine hypotension syndrome (SHS) has been reported to occur due to compression by a giant tumor such as ovarian tumor. We herein report a case of retroperitoneal ganglioneuroma with SHS treated with laparoscopic resection.Case presentationThe patient was an 11-year-old male with right-sided abdominal pain. He had a pale complexion and tachycardia while falling asleep. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a giant mass lesion (60 × 35 mm) with compression of the inferior vena cava (IVC) and duodenum ventrally and the right kidney caudally. The IVC was flattened by mass compression. Abdominal ultrasonography (US) revealed narrowing of the IVC due to the mass and accelerated blood flow after IVC stenosis in the supine and left lateral recumbent position. His pale complexion and tachycardia while falling asleep was thought to be due to decreased venous return caused by the tumor compressing the IVC, resulting hypotension. 123I-MIBG scintigraphy revealed no abnormal findings. Tumor markers were normal. He was diagnosed with SHS due to a right adrenal gland tumor. The tumor compressed the IVC from the dorsal side, and hemostasis was expected to be difficult during bleeding. Therefore, a guidewire was inserted from the right femoral vein into the IVC for emergency balloon insertion during bleeding. A laparoscopic tumor resection was performed. A histopathological examination confirmed the diagnosis of primary retroperitoneal ganglioneuroma.ConclusionsThe treatment of symptomatic retroperitoneal tumors requires a multidisciplinary approach.

Giant mucinous liposarcoma of the abdominal cavity: A case report.

Mucinous liposarcoma myxoid liposarcoma is a malignant mucoid soft tissue tumor derived from undifferentiated stromal cells in perivascular, subbody cavity and intermuscular space, and composed of cells at different stages of differentiation from preadipocytes to mature cells. In rare cases, it may change from lipoma malignancy. The main manifestations is painless mass, relatively slow growth, the course can last decades, the prevalence of liposarcoma in the population is 14% to 18%, mainly in adults, male prevalence is higher than women, but not significant. The main good hair part is the thigh, have mucinous sex, high differentiation type, dedifferentiation type, polymorphic type. Clinical diagnosis is difficult, and there are no obvious symptoms in the early stage, so the diagnosis should be combined with B ultrasound, MRI, CT, and other auxiliary examinations. The gold standard is pathological examination. In December 2023, our department admitted a patient with a mucinous abdominal mass. The report is as follows. Does liposarcoma metastasize? Is any chemotherapy required after surgery? Will it ever relapse in the future? What is the survival period after surgery? Mucinous liposarcoma. Surgical resection of the sarcoma. The nodule sample was 33 * 28 * 13 cm, with complete capsule, gray and yellow sections, fine texture, soft, gray, red, grayish, and yellow mucoid nodules in some areas, and the maximum diameter of the nodules was 21cm. Immunohistochemistry was: CD34 (+), CDK 4 (+), CK (-), Desmin (weak +), Ki67 (index 5%), MDM 2 (-), p16 (weak +), S-100P (+), Vimentin (+), BCL-2 (+). He was also sent to the Department of Pathology of Peking Union Medical College Hospital for consultation with Professor Lu Zhaohui, whose consultation opinion was in line with myxoliposarcoma. Retroperitoneal liposarcoma is a common retroperitoneal tumor, but it is relatively rare in clinical practice; the overall morbidity is low, mainly manifested as abdominal pain and abdominal distension, abdominal distension, and a long course of disease; it is not sensitive to radiotherapy and chemotherapy, and should be closely follow up by CT examination to understand the recurrence and metastasis.

Laparoscopic removal of retroperitoneal schwannoma in renal hilum: a case report

BackgroundSchwannomas in the renal hilum are rare among retroperitoneal tumors. However, the possibility of malignant findings cannot be ruled out, and surgery is often indicated. This case was expected to be difficult to remove laparoscopically because the tumor was sandwiched between the arteriovenous veins of the renal portal. Sometimes, the tumor should be resected with a conservative approach to the kidney to preserve the renal function.Case presentationOur patient was a 51-year-old Asian-Japanese man who was referred to our department for a retroperitoneal tumor in the renal hilum. Since malignancy could not be ruled out due to its size (45 × 48 × 55 mm) on imaging, the tumor was excised laparoscopically. Histopathology revealed schwannoma.ConclusionsWe herein report a case in which a renal hilar tumor between renal arteriovenous vessels was successfully resected laparoscopically.

Cadaveric analysis of surgical techniques and working space for retroperitoneal tumors as model for improving resection of neuroblastoma

PurposeNeuroblastoma, the most common extracranial solid tumor in children under 5 years, often surrounds visceral arteries. This study aimed to analyze the working space provided by standardized surgical techniques at key arterial landmarks in adult cadavers.MethodsWe assessed in eight adult cadavers the mobilization of the left colon, spleen and pancreas, right colon, duodenum and mesenteric root, access to the bursa omentalis. The average working space score (AWSS) was evaluated at the left and right renal artery, left and right side of the coeliac trunk, superior mesenteric and common hepatic artery. The score was defined as: (0) vessel not visible, (1) working space at the vessel ≤ 1x diameter of the aorta, (2) < 3x the diameter of the aorta, (3) ≥ 3x diameter of the aorta.ResultsThe maximum AWSS of 3 was achieved at key vascular landmarks through specific mobilization techniques.ConclusionAdditional mobilization of spleen, pancreas and mesenteric root and access to the bursa omentalis increase surgical working space at major visceral arteries. The results of our investigation provide surgeons with a useful guide to prepare for abdominal neuroblastoma resection.

Incidental discovery of unilateral hydronephrosis unveiling psoas major desmoid-type fibromatosis in a 24-year-old male: A case report with a 5-year follow-up.

Desmoid-type fibromatosis (DTF), also known as aggressive fibromatosis, is a rare neoplasm originating from the fascial or musculoaponeurotic tissues. While benign and characterized by slow growth, it exhibits local aggressiveness and lacks specific clinical characteristics. However, in a considerable percentage of patients, it could be asymptomatic and discovered by accident during routine clinical examinations. Only a few cases of DTF arising from the psoas major muscle have been reported in the medical literature. A 24-year-old male, asymptomatic and without significant personal or family medical history, was diagnosed with grade 2 hydronephrosis by abdominal ultrasonography during a routine physical examination. This diagnosis was made 15 days after undergoing uncomplicated open-heart surgery to repair an atrial septal defect. Intravenous pyelogram revealed hydronephrosis with dilation of the pelvicalyceal system. Ureteroscopy ruled out any intrinsic lesions of the ureter. Contrast-enhanced computed tomography identified a 3.5 × 2 × 5.2 cm mass in the retroperitoneum, closely associated with the psoas muscle and enveloping the ureter adjacent to the iliac artery. Postoperative pathological analysis confirmed a definitive diagnosis of sporadic DTF. The patient underwent exploratory abdominal surgery, during which the tumor was resected without any intraoperative complications. After close monitoring over a 5-year follow-up period, which included periodic physical examinations, magnetic resonance imaging, and ultrasonography, no local recurrence was detected. Achieving an accurate preoperative diagnosis presents a challenge in cases involving retroperitoneal tumors originating from the psoas major muscle and encasing the ureter. However, the insertion of a double J stent is deemed a crucial step in the surgical process, facilitating the dissection and isolation of the ureter from the tumor while preserving kidney function.

A Rare Case of Retroperitoneal Schwannoma in an Adult Male

Objective. This study aims to illustrate a rare case of retroperitoneal schwannoma by presenting the clinical, imaging, and histological parameters. Case Report. A 36-year-old patient visited the outpatient clinic because of back pain experienced over the previous two months. There were no complaints regarding the nervous system or urinary system. Thorough imaging evaluation, including magnetic resonance for the lumbar spine, abdominal computed tomography, and positron emission tomography was conducted. An encapsulated mass was found in the retroperitoneal area, positioned in front of the O4 vertebra and in close proximity to the left psoas muscle, the left common iliac artery, and the left ureter. The lesion exhibited FDG radioisotope uptake, and a CT-guided biopsy confirmed a benign peripheral nerve tumor. The patient underwent laparotomy surgery, where the tumor was removed. The histological investigation, along with immunohistochemistry, confirmed the presence of a retroperitoneal schwannoma. Conclusion. Schwannoma is a rare type of retroperitoneal tumor, with nonspecific clinical and radiological characteristics that make diagnosis difficult. Surgical resection is the primary treatment for symptomatic patients, with a favorable prognosis. Long-term follow-up is advised to reduce the chance of late recurrence.