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 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.

Growing teratoma syndrome (GTS) represents a rare yet significant complication following treatment for non-seminomatous germ cell tumors (NSGCT), characterized by the growth of mature teratoma elements despite prior chemotherapy. We present the case of a 30-year-old male who, following orchidectomy for NSGCT and subsequent chemotherapy, developed acute abdominal pain and pulmonary metastasis. Despite normal serum tumor markers, imaging revealed a large retroperitoneal mass encasing significant vessels. Surgical excision led to symptom resolution. This case underscores the diagnostic challenges GTS poses, the importance of imaging in diagnosis, and the efficacy of prompt surgical intervention in achieving favorable outcomes.

Non-seminomatous germ cell tumors with structural components from all three cellular lineages are called teratomas. We report a rare case of a primary right adrenal teratoma in a postmenopausal female, presenting with abdominal pain. Ultrasound revealed a complex cystic shadow in the perihepatic region superior to the upper pole of the right kidney, which was suggestive of a complex supra-renal space-sequence-occupying lesion. Computerized tomography revealed a large-sized mature single multilobulated complex cystic lesion in the right hypochondrial lumbar region arising from the right adrenal gland. A right-sided transperitoneal adrenalectomy was performed. The resected mass (18 × 13 × 10 cm) was well encapsulated. Cut surfaces showed cystic mass filled with necrotic gray-white pultaceous material, along with a solid white gelatinous area. Microscopic sections showed a tumor which displayed differentiation along various tissue lineages. After immunohistochemical examinations, the tumor was confirmed to be a mature cystic teratoma. Mature teratomas show a good prognosis, and surgical resection and follow-up remain the standard approach.

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.

Retroperitoneal ganglioneuroma is a rare benign tumor that is challenging in terms of clinical diagnosis. Computed tomography and magnetic resonance imaging are usually performed for diagnosis rather than convenient and inexpensive ultrasonography. Here, we present the case of a 21-year-old female patient who was diagnosed by multimodal ultrasound imaging and whose diagnosis was confirmed by ultrasound-guided core needle biopsy before surgery. We hope that this rare case will help clinicians and radiologists realize the advantages of multimodal ultrasound imaging in the diagnosis of retropeitoneal solid tumors, and reduce misdiagnosis.

Pulmonary sequestration is a congenital malformation of lung development in which part of the lung tissue is separated from the normal lung during the embryonic phase and develops separately and receives blood supply from an aberrant systemic artery forming a nonrespiratory mass. In brief, early in embryonic development, certain tissues that should have atrophied and been gradually absorbed are left behind due to impairment of the atrophy process and form anomalous branches of the aorta, which pull parts of the lung tissue, isolating them from normal lung tissue and bronchi, and thus forming separate lung tissue. According to the relationship of the mass to the pleural covering, pulmonary sequestration can be divided into two types, intralobar pulmonary sequestration (ILS) and extralobar pulmonary sequestration (ELS), of which approximately 75% of cases are ILS, but ELS is less common. Symptoms are not obvious in either type, making diagnosis and differential diagnosis more difficult. Here we report a 33-year-old patient with only insignificant abdominal distension who was eventually diagnosed with retroperitoneal ELS.