Ectopic hepatocellular carcinoma (HCC) is defined as HCC arising from hepatic parenchyma located in an extrahepatic organ or tissue without any communication with the mother liver. It is very rare and difficult to diagnose by imaging alone. We report a case of a rare ectopic HCC mimicking a right para-aortic retroperitoneal mass and present a review of the literature. It is about a 79-year-old female patient, who presented with a progressive enlarged right paraaortic retroperitoneal mass, thought first to be leiomyosarcoma of vena cava on imaging. Subsequently, high alpha-fetoprotein (AFP) level and biopsy allowed the diagnosis of primary extrahepatic hepatocellular carcinoma.

Testicular choriocarcinoma is a relatively rare malignancy with a highly aggressive nature. Timely diagnosis and treatment can help prolong the survival of patients and even cure them. This case reports a 29-year-old male who presented to the clinic for a month with epigastric pain. On examination, a massive mass of approximately 9*10 cm could be palpated in the upper abdomen. When asked about his previous history, the patient only described a history of a right inguinal hernia that had been repaired 12 years earlier. The admission diagnosis was considered the retroperitoneal tumor, which was found to have metastasized to the liver and lungs after the completion of relevant tests. We then performed a CT-guided lune puncture biopsy on day 8 of admission. The biopsy pathology suggested metastatic cancer was considered. As the symptoms of tumor compression gradually worsened, we performed surgical treatment (retroperitoneal tumor resection + partial duodenal resection + enteroanastomosis) on day 13 of admission. The postoperative pathology was choriocarcinoma. We subsequently conducted a detailed inquiry with the patient\'s family about his medical history and found a history of inguinal testicle. Through testicular ultrasound examination, it was preliminarily determined to be testicular choriocarcinoma (not yet pathologically confirmed). We wanted to start salvage chemotherapy as soon as possible after surgery. However, the patient\'s postoperative condition was poor, with rapid progression of hepatopulmonary metastases and gradually increased thyrotoxicosis, and we started salvage chemotherapy (EP regimen: etoposide and cisplatin) on postoperative day 12. However, the patient was forced to stop due to a severe chemotherapy reaction and died of respiratory and cardiac arrest in the hospital. For male patients with retroperitoneal mass, the possibility of germ-cell neoplasm should first be excluded. By inquiring in detail about a history of cryptorchidism and in the initial days of hospitalization, testicular exploration, ultrasounds, and serum tumor markers (AFP, β-HCG) tests can be conducted to rule out the possibility of germ-cell neoplasm, thereby preventing misdiagnosis and treatment delays. If the clinical diagnosis is metastatic germ-cell tumor with severe symptoms of metastatic disease, surgery should never be used as the initial treatment.

Testicular tumors represent a common form of solid tumor in young men, with choriocarcinoma of the testis being a rare, non-granulomatous germ cell tumor. It accounts for less than 0.3% of all testicular germ cell tumors. Pelvic and pulmonary metastases originating from testicular choriocarcinoma are exceptionally uncommon in men. This study describes a case of a 27-year-old male diagnosed with testicular choriocarcinoma, presenting initially with nausea, vomiting, and abdominal pain. Furthermore, this review encompasses cases of testiclar choriocarcinoma in individuals aged 30 years and below, both in China and internationally, over the past 20 years.

UNASSIGNED: Epithelioid angiomyolipoma (EAML), a subtype of angiomyolipoma, is distinct. It has a biologic behavior of borderline tumor, a malignant tendency, and a risk of metastasis and recurrence. Adrenal EAML is very rare. It is true that only six cases of adrenal EAML have been documented in the English-language literature.
UNASSIGNED: A 65-year-old man who underwent a laparoscopic left adrenalectomy in July 2022 has adrenal EAML and this is a case report about it. The mass was surrounded by abundant blood vessels and adherence with surround-tissue. Postoperative pathology of the tumor analysis revealed adrenal epithelioid vascular smooth muscle lipoma. The patient underwent left upper abdomen and lumbar pain in July 2022. The enhanced computed tomography (CT) scan of the abdomen showed markedly enhanced masses in and around the left adrenal gland. A second left laparoscopic adrenalectomy was performed under general anesthesia. Postoperative pathology showed two taupe nodules of left adrenal, maximum diameter 0.9 to 1.1 cm. The postoperative pathological diagnosis in combination with immunohistochemistry was EAML. The patient was discharged 10 days later with symptomatic treatment with low molecular heparin.
UNASSIGNED: Adrenal EAML has a biologic behavior of borderline tumor with malignant potential and a risk of distant metastasis and recurrence. Therefore, radical surgical resection should be considered as its necessary treatment. Long-term postoperative follow-up is an important part of the treatment.

We describe a unique presentation of acute lower limb ischaemia due to metastatic seminoma in a middle-aged man with a large retroperitoneal mass. The patient underwent vascular bypass surgery of the right lower limb, completed chemotherapy, and had a right scrotal orchiectomy. The patient had pre-existing vascular risk factors including peripheral vascular disease and smoking. To our knowledge this is the first published case in the literature that has described a large retroperitoneal seminoma compressing the abdominal aorta resulting in acute lower limb ischaemia.

We present a unique case of a retroperitoneal tumefactive fibroinflammatory lesion related to IgG4-sclerosing disease; it is a rare manifestation of the IgG4-related disease, which usually causes diffuse fibrosis when located in the retroperitoneum, rather than mass-like lesions. A 49-year-old man presented to the emergency department complaining of abdominal pain and vomiting. Subsequent testing with abdominal ultrasound, CT, and MRI revealed a large retroperitoneal mass of unknown origin, heterogenous, with a concentric circles pattern best visualized in MRI. The lesion was resected, and the histological and immunohistochemical studies revealed an IgG4-related tumefactive fibroinflammatory lesion of the retroperitoneum.

An elderly man was referred to vascular surgery on incidental discovery of a left retroperitoneal mass ultimately found to be of left renal vein (LRV) origin. He initially presented with recurring lower back pain. CT of the abdomen/pelvis showed a 6.0×5.5 cm lobulated retroperitoneal mass anterior to the infrarenal aorta. Resection of the mass necessitated a multidisciplinary team consisting of medical oncologists, radiation oncologists, urologists and vascular surgeons. In efforts to obtain an R0 margin, en-bloc resection of the LRV from its confluence with the inferior vena cava (IVC) was necessary. A primary repair of the IVC was performed with preservation of the left kidney. The patient\'s back pain has since resolved after the surgery. A literature search found IVC reconstructions to be safe and effective in the removal of vascular leiomyosarcomas.

UNASSIGNED: Malignant etiologies are found in 70-80% of symptomatic retroperitoneal masses. Histology is required for diagnosis and treatment. Information about endoscopic ultrasound (EUS)-guided tissue acquisition (EUS-GTA) is scant for retroperitoneal masses. This study aimed to assess the pathology results of EUS-GTA for diagnosing retroperitoneal masses.
UNASSIGNED: This retrospective, multicenter study involved patients from 5 care centers. All patients with retroperitoneal masses who underwent EUS evaluation were enrolled. We recorded demographic and clinical characteristics, location and size of the mass, type of needle (FNA/FNB), and complications related to the procedure.
UNASSIGNED: A total of 43 patients were included. The median age was 50.5 (range: 23-83) years, and 22 (51.2%) were female. The initial symptom was abdominal pain in 23 (52.3%) cases and weight loss in 11 (25%). Initial imaging was by computed tomography in 33 (75%) patients. Diagnosis with EUS-GTA was reached in 67.5% (29/43) cases. The most frequent histological diagnosis was carcinoma, in 25.5% (11/43). A malignant etiology was found in 31 (72%): 20 were primary tumors from the retroperitoneum, and 11 were metastases. In patients with metastasis, surgery was avoided and medical treatment was indicated. No adverse events were reported.
UNASSIGNED: EUS and EUS-GTA can frequently provide accurate tissue diagnosis and significantly impact the subsequent management.

Echinococcal disease (hydatid disease (HD) is an endemic parasitosis caused by Echinococcus granulosus in the larval stage, and it is typically due to the production of unilocular cystic lesions, usually involving the liver for the majority of patients and the lungs in 25%, but also any other organs can be potentially involved in developing echinococcal disease. We report a case of extrahepatic, retroperitoneal echinococcal disease, caused by Echinococcus granulosus. The patient underwent a surgical removal of the abdominal mass, revealed by abdominal ultrasound and computerized tomography scanning, and in the founded clinical and radiological suspicion of echinococcal disease, multiple bioptical samples were sent for microbiological analysis and albendazole therapy was started; Echinococcus granulosus protoscolices were found on the bioptical sample, and the diagnosis was successfully confirmed. According to the current parasitology literature on echinococcal disease, extrahepatic localization, although rare, can be found, and it should be considered in the differential diagnosis of an abdominal mass when epidemiological risk factors and anamnestic data are present, regardless of the usual site of the disease.

OBJECTIVE: To explore the feasibility, safety, and clinical application value based on the fusion image of 18 F-FDG PET/CT, for guiding retroperitoneal puncture biopsy technology and to determine the diagnosis of retroperitoneal masses in diagnosing malignant tumors.
METHODS: From March 2019 to January 2023, 42 patients underwent 18 F-FDG PET/CT imaging and were found to have retroperitoneal lesions that required definite diagnosis; 22 were male, 20 were female, and the average age was(59.17 ± 13.23) years. According to the fused 18 F-FDG PET/CT tomographic image, the target point with the highest metabolic activity, the safest, and expected maximum sample size was selected. CT scans were acquired with the same machine and fused with 18 F-FDG PET, guiding the puncture biopsy needle to approach the expected target zone, enabling timely delivery of pathological and immunohistochemical examination of the biopsy. Success rate, total examination time, biopsy operation time, complications, CT radiation dose, pathological, and immunohistochemical results were recorded.
RESULTS: All 42 patients were sampled successfully with the successful rate being 100%. The site of sampling of 42 patients accurately targeted the highest metabolic activity, the safest, and the expected maximum sample size. All 42 patients received clear diagnosis (25 cases of malignant tumors and cases of 17 benign tissues). 15 cases of patients had a change in clinical diagnosis, accounting for 35.7% of all patients, and affecting subsequent treatment plans. The average total examination time for patients was (41.3 ± 7.3) minutes, and the biopsy operation time was (29.1 ± 8.7) minutes. The effective radiation dose generated by the entire examination generated by CT guidance was (2.0 ± 0.5) mSv; no severe complications occurred in the patients.
CONCLUSIONS: Real-time-guided retroperitoneal puncture biopsy based on 18 F-FDG PET/CT fusion image is safe, accurate, and feasible, and can provide patients of retroperitoneal mass with clear pathological diagnosis and immunohistochemical evaluation.