primary retroperitoneal tumors ( prts ) of vascular origin are a diverse group of rare abdominal neoplasms , both benign and malignant . the most frequent malignant tumors are liposarcoma and leiomyosarcoma , while the most often found benign tumors are lipoma , leiomyoma and cavernous hemangioma [ 25 ] . hemangiomas are a group of neoplasms originating from vascular tissue where benign tumors prevail . among these capillary hemangioma , cavernous hemangiomas most frequently occur in the liver . other described localizations are skin , muscles , bones , central nervous system and retroperitoneal organs ( intestines , kidneys , adrenal glands , urinary bladder , uterus ) [ 616 ] . an interventional staged therapy is becoming more popular with the aim of reducing the diameter of the main hemangioma , especially that surrounded with diffuse hemangiomatosis . successful combination of transcatheter arterial embolization ( tae ) prior to the surgery of cavernous hemangioma of the liver was reported recently . nevertheless , the treatment of choice for primary retroperitoneal tumors is still radical surgical resection that leads to recovery . surgical techniques used for treatment of prts are : open procedures , laparoscopy , surgical endoscopy and percutaneous radiofrequency ablation [ 8 , 19 ] . the present case is a patient with giant retroperitoneal cavernous hemangioma originating from the ilium with atypical clinical course who was referred for surgical treatment . a 71-year - old female patient was referred to the department of surgical oncology with a giant retroperitoneal tumor located in the left iliac fossa . the patient discovered the abdominal tumor 15 years earlier , but as it did not cause any problems she refused to seek medical help . several months prior to admission to the department the first symptoms appeared : left lower limb edema , exertional dyspnea , abdominal distension and anemia with pallor and lowered hemoglobin level . physical examination revealed a large , skin modeling , nonpulsatile mass in the left iliac fossa ( fig . b  computed tomography scan revealing a large , left - sided retroperitoneal mass when abdominal contrast - enhanced computed tomography ( ct ) was performed , a tumor 20  17  18 cm in diameter lying on the iliac ala was found ( fig . an ultrasonography - guided fine needle biopsy was performed , revealing blood cells with necrotic masses and connective tissue which prevented precise diagnosis . blood laboratory findings were : anemia ( hb 8.8 g / dl ) , elevated white blood cell count ( 21.81 g / l ) and high c - reactive protein level ( 100.8 mg / l ) . because of uncertainties regarding the histological type of the tumor , escalation of abdominal pain and left lower limb edema in recent weeks and the patient s strong willingness to remove the tumor , the decision to perform laparotomy was made ( figs . 2 a , b ) . 
 a  giant tumor with sigmoid colon tight on it . c  the tumor after resection ( arrow  peduncle connecting the tumor to the ala ) during the surgery a large mass on the ala was found . there were no signs of infiltration of neighboring organs , and the sigmoid colon was tight on the tumor . after separating the sigmoid and identification of the left ureter and iliac vessels massive damage to the internal surface of the ala was found in the place where the tumor grew . pathologic examination showed a tumor 20  19  16 cm in diameter , weighing 3000 g ( fig . histochemically the cells lining the lacunae were stained positively by markers for cd34 ( figs . 3 a , b ) . 
 a  microscopic image with h&e ( enlargement 10 ) . diag . staining with markers for cd34 confirm an endothelial origin of the cells lining the lacunae the postoperative follow - up is 3 years . within this time limb edema and this is caused by its initially symptomless course and therefore delayed presentation to a physician . the most frequent symptoms of retroperitoneal tumors are non - specific abdominal pain ( 51.8% ) and abdominal distension ( 18.7% ) . less frequent symptoms include constipation ( 8% ) , fever ( 8% ) , dysuria ( 4.3% ) , lower limb edema ( 6.5% ) , weight loss and cachexia ( 5% ) . the time of these symptoms occurrence varies from several months for sarcomas to years for benign tumors . patients usually visit a physician when they discover a pathological mass in the abdomen ( 60.4% ) . in the present case her first symptoms ( abdominal distension and limb edema ) occurred 15 years after discovering the tumor . on ct images retroperitoneal tumors present as heterogeneous pathological masses with hypoechogenic areas corresponding to necrotic zones in the tumor . we considered an interventional staged therapy with tae for its possible advantage of reduction of the diameter of the main tumor mass , and surrounding diffuse hemangiomatosis , which was reported in the case of cavernous hemangioma of the liver . the age of the patient with possible diffuse arteriosclerosis and the necessity to resect the symptomatic tumor were the arguments to abandon the percutaneous option . however , one can find publications on treatment of hepatic cavernous hemangioma with percutaneous radiofrequency ablation . in the present case the size and localization of the tumor and urgent necessity made the operation a high - risk procedure with possibility of resecting vital structures , such as the sigmoid colon or ureter . in the present case the long - term history of abdominal tumor indicated a benign tumor , while radiological and clinical findings suggested malignant disease . the literature review shows that in differential diagnosis of giant abdominal tumors , rare benign neoplasms should be considered in every case . radical surgical resection resulted in full recovery in our patient , which corresponds to commonly found conclusions despite the huge diameters and the origin of retroperitoneal tumors [ 20 , 21 ] . in the literature reports we found only 15 cases of retroperitoneal cavernous hemangiomas in kidneys , adrenal glands , urinary bladder , uterus and the retroperitoneal part of the rectum [ 615 ] . however , no description of cavernous hemangioma of the ilium was found ; therefore our report seems to be a unique contribution to contemporary knowledge ( tab . because of their initially symptomless course , primary retroperitoneal tumors are usually diagnosed in an advanced stage of the disease , which is the reason for many uncertainties regarding safe surgical resection . radical surgical resection remains the treatment of choice for primary retroperitoneal cavernous hemangiomas , although the decision of performing such operations should be taken after thorough analysis of indications ( escalation of symptoms ) and contraindications ( risk of damaging vital retroperitoneal organs with massive bleeding ) .
retroperitoneal hemangiomas are very rare . 
 this paper presents the case of a 71-year - old female patient with giant cavernous hemangioma of the retroperitoneum who underwent surgical treatment for abdominal pain and left lower limb edema . 
 interventional staged treatment with percutaneous transcatheter arterial embolization prior to surgery was considered . 
 radical resection of the tumor was performed , which caused the symptoms to abate . 
 additionally a literature review of cases involving cavernous hemangioma in the retroperitoneal space is presented . 
 no description of retroperitoneal cavernous hemangioma originating from the bowel was found in the analyzed reports .