Malignant extragonadal germ cell tumors can arise anywhere along the gonadal ridge. Locations may include the retroperitoneal, mediastinum, presacral region, and pineal gland [1]. An Extragonadal Germ Cell Tumor (EGCT) is by definition a germ cell neoplasm displaying one of the histologies associated with gonadal origin, but located outside of the gonads [2]. EGCT arise from primordial germ cel...

Solitary fibrous tumor (SFT) is a rare spindle cell neoplasm mainly originated in the pleural cavity. We report here an unusual case of a large SFT in the retroperitoneum. A 27-year-old female complaining of a palpable mass in the right flank with dull pain was admitted to our hospital with the diagnosis of right retroperitoneal tumor. Computed tomography (CT) and magnetic resonance imaging (MR...

Merkel cell carcinoma (MCC) is an extremely rare primary neuroendocrine neoplasm of the skin that shows aggressive behavior and a poor prognosis. We report a case of a 67-year-old male with a Merkel cell carcinoma which initially presented itself as a large retroperitoneal mass. Pathological and immunohistochemical analysis revealed tissue consistent with neuroendocrine carcinoma. Despite compl...

Primary renal Angiosarcoma is a rare neoplasm and only 24 cases have been reported in specialized literature. We describe a case of primary renal angiosarcoma in a patient presenting with hematuria, palpable abdominal mass, left flank pain and anemia. A computerized tomography of the abdomen with contrast medium showed a tumor with 15 cm diameter, in the upper pole of the left kidney, with a lo...

Malignancies such as solid tumors and hematologic malignancies can often induce or be associated with Henoch-Schönlein purpura (HSP) in older males but not in children. Described here is the case of a 5-year-old boy who clinically presented with HSP. An imaging study of the abdomen revealed a right retroperitoneal neoplasm that histopathology postoperatively confirmed to be a neuroblastoma. Mal...

Follicular dendritic cell sarcoma is a rare neoplasm that originates from follicular dendritic cells in lymphoid follicles. This disease usually involves the lymph nodes, and especially the head and neck area. Rarely, extranodal sites may be affected, including tonsil, the oral cavity, liver, spleen and the gastrointestinal tract. We report here on the imaging findings of follicular dendritic c...

BACKGROUND Isolated retroperitoneal cystic masses are uncommon with an estimated incidence of 1/5750 to 1/250,000. The majority present with size related symptoms, complications, or a mass. Approximately a third of patients are asymptomatic and are diagnosed incidentally. Aetiologies of retroperitoneal cystic masses (RPC) include mesenteric, omental, splenic and enteric duplication cysts. Neopl...

Alveolar soft part sarcoma (ASPS) is a rare type of neoplasm, typically occurring in adolescents and young adults. Because of the rarity of this disease, there is no standard treatment plan. Chemotherapy and radiotherapy are not effective in this type of malignancy. Surgical excision is considered to be the treatment of choice. We report a case of a young woman with a painless mass in her left ...

A 74-year-old man presented with right flank pain and a palpable mass in the left flank. Blood pressure was normal. Contrastenhanced computed tomography (CT) showed a 17 × 16 × 12 cm retroperitoneal mass over the left kidney, solid and heterogeneous. There were also 3 retro aortic lymph nodes and bilateral renal lithiasis. Twenty four-hour urinary metanephrines and normetanephrines were normal....

INTRODUCTION Lymphangiomas are rare, benign tumors. An intra-abdominal location of these lesions is rarer still and there are only a few reports describing laparoscopic resection for retroperitoneal lymphangiomas, especially in tumors that mimic pancreatic tumors. CASE PRESENTATION We present the case of an asymptomatic 30-year-old Japanese woman in whom a cystic tumor was found incidentally ...