spinal angiolipomas , benign tumors of fatty tissue of the spinal axis , are very rare3,13 ) . they are usually present with slowly progressing signs and symptoms of cord compression from an epidural mass13 ) . this predilection may be explained by the tenuous blood supply of the thoracic spine with subsequent neovascularization of the ischemic area8 ) . angiolipomas are distinct entities from lipomas as they contain vascular tissue occurring mainly in adults and lack associated malformations13 ) . spinal angiolipomas are composed of mature fat cells and abnormal blood vessels that vary from capillary through sinusoid or venular to arterial in size3,10 ) . the infiltrating ones are partially or entirely unencapsulated , ill - defined , and infiltrate the surrounding tissues , especially the bone2,5,9 ) . gelabert - gonzlez and garca - allut4 ) reviewed the literature of spinal angiolipoma since 1892 and found 123 cases of spinal angiolipomas . to the best our knowledge , approximately 18 cases of spinal infiltrating angiolipoma have been reported in the medical literature . this report now presents a case of thoracic infiltrating angiolipoma and reviews the literature on this rare entity . a 58-year - old man was presented with progressive weakness and sensory change in the lower extremities for seven months . neurological examination revealed weakness of lower extremities ( manual muscle testing , mmt grade 4 ) and hypesthesia below the level of t10 . deep tendon reflexes were hyperactive on the right leg . spine computed tomography ( ct ) scan revealed that the mass lesion compressed the spinal cord severely in the posterior extradural space at the t4 - 5 level , and it extended into the right t4 - 5 neural foramen to the paraspinal space . due to the mass , right t4 - 5 the infiltrating epidural thoracic mass showed iso - signal intensity on t1-weighted image ( wi ) , slightly high signal on t2wi , and homogenous enhancement with gadolinium ( fig . afterwards , a total laminectomy of lower t3 , t4 , and t5 , epidural fat was encountered at both the upper and lower end of the lesion . below the epidural fat , the reddish - gray colored and highly vascularized mass appeared . the mass was removed by piecemeal pattern and dissected from the dura in spite of profuse bleeding . we excised all of the epidural mass but left behind a tumor part of the paraspinal portion . 3 ) . immunohistochemistry stained positive for cd34 and smooth muscle actin ( sma ) that were consistent with an angiolipoma . the patient showed improvement in strength ( mmt grade 4 + ) and sensation in the days following surgery . follow - up thoracic ct 18 months after surgery did not show recurred posterior epidural mass lesion except the remnant paraspinal lesion ( fig . however , the term angiolipoma was recognized in 1960 by howard and helwig as an anatomopathological entity containing mature fat cells and proliferating vessel6 ) . bardosi et al.1 ) postulated that angiolipomas originate from adipocytes with secretory activity containing lipid - like material in perivascular granules . plain radiography is often negative , whereas infiltrating tumors cause trabeculation of the affected vertebral body7 ) . ct scan demonstrates a hypodense lesion and provides information on the degree of bony involvement7,13 ) . spinal epidural angiolipomas are usually hyperintense and inhomogeneous on t1wis with intense homogeneous enhancement5,13 ) while t2wi can be variable , but are usually hyperintense4,13 ) . in the current case , iso - intensity on t1wis correlated with increased vascularity within the spinal angiolipoma . noninfiltrating and infiltrating angiolipomas are considered histologically benign , although infiltrating angiolipomas have a locally aggressive nature and can erode the local bone , muscle , and neural and fibrocollagenous tissues12 ) . the signs and symptoms do not differ from any other benign spinal tumors and the duration of symptoms is usually long in both non - infiltrating and infiltrating types5 ) . the majority of cases ( 76% ) were epidural without local infiltration , whereas the infiltrated vertebral bone ( 17% ) , with or without extension into the thoracic cavity , and intramedullary lesions ( 5% ) were likewise presented . surgery appears to be the treatment of choice , and complete excision appears to be curative in most cases3,4,13 ) for the infiltrating type , a total resection can be more difficult . however , most patients have a good prognosis even with subtotal removal as these lesions are slowly growing and do not undergo malignant transformation5 ) . our case with subtotal resection presents no recurrence after 18 months of follow - up . no adjuvant radiation should be applied to patients with this benign pathological entity , even in the infiltrating group4 ) . while symptoms may vary , the prognosis after surgical management of this lesion is favorable .
spinal angiolipomas are rare lesions usually found in the epidural space of the thoracic spine . 
 the infiltrating type of spinal angiolipomas is extremely rare . 
 this report presents the case and reviews the related literature . 
 a 58-year - old man was presented with a 7-month history of progressive weakness and sensory change of lower extremities . 
 magnetic resonance images showed a well - enhanced mass infiltrating the vertebral foramen at the t4 - 5 level . 
 resection of the tumor was performed . 
 histological study revealed the tumor as an angiolipoma . 
 the patient was relieved from symptoms after tumor resection .