. two distinct types of neurofibromatosis including neurofibromatosis type 1 ( nf1 ) and neurofibromatosis type 2 ( nf2 ) have been recognized according to the different clinical manifestations and genetic mutation . plexiform neurofibroma ( pn ) , a special subtype of nf1 , is a rare , slow - growing benign tumor . although previous study presented one case with pn in the craniomaxillofacial region , the entity with hemorrhage in this region on ct and mri has not been described . we report here the radiological findings of a giant hemorraghic pn in the cranio - maxillofacial region to illustrate the usefulness of ct or mri in making diagnosis . a 21-year - old man presented with a mass on the right side of his face for 16 years , which had initially appeared as a small cutaneous protuberance with a size of 2 cm in diameter in the right zygomatic arch region . the mass gradually enlarged and involved the right scalp , eye and face , and the color turned darker and darker with time . nine days before admission , the lesion grew abruptly , which resulted in cosmetic impairment of right face accompanied by severe headache , and the proptosis of the right eye and loss of eyesight . no other first - degree relatives in his family were noted nf1 besides his grandmother with neurofibroma alongside of left eye . nine days after abrupt enlargement , the patient was admitted for treatment , and emergent ct was performed . the next day after the admission , the patient underwent enhanced ct and mri scans of the craniomaxillofacial region . the studies revealed a giant cystic and solid mass with the size of 30 cm  25 cm  16 cm , involving the right eye , right auricle , and subcutaneous and deep soft tissues in the face . the cyst within the mass was filled predominantly with subacute hemorrhage appearing as hyper- and iso- attenuation on plain ct scan ( figure 1a ) and non - enhanced on contrast - enhanced ct image ( figure 1b ) , heterogeneously low to high signal intensity on t1-weighted image , and intermediate to light high signal intensity on t2-weighted image ( figure 1d - e ) . the small amount of solid components presented with heterogeneously intermediate to low signal intensity on non - enhanced t1-weighted image and intermediate to high signal intensity on t2-weighted image , and light enhancement on contrasted - enhanced t1-weighted image . heterogeneous enhancement and small abnormal vessels were seen within the solid lesion of the mass on contrast - enhanced ct and mri , whereas no enhancement was found in the cyst . bony defects were found within the cavalla , temporal bone and top of fossa orbitalis on ct and mri , and the adjacent right skull base was thickened and sclerotic on ct . the dysplastic right temporal lobe complicated with a meningoencephalocele the optic nerve and extraocular muscles were involved by the mass , the ct surface shaded display ( ssd ) reconstruction showed the cosmetic impairment of right face proptosis of the right eye and the right ear was lower than normal in location(figure 1c ) . a 21-year - old man with plexiforma neurofibroma in the right cranio - maxillofacial region . ( a ) non - enhanced ct demonstrates a giant cystic - solid mass in the right craniomaxillofacial region , and the cyst of the mass appearing as hyper- and iso- attenuation ( white arrows ) . ( b ) contrast - enhanced ct depicts the mass appearing as no enhancement ( arrows ) . ( d ) on t1-weighted mr image , the cyst of the mass shows heterogeneously intermediate to high signal intensity ( arrows ) . ( e ) the cyst of the mass shows light low to intermediate signal intensity on t2 weighted mr image ( arrowhead ) with a low - signal ring around the hematoma ( thin arrows ) . subsequently , the patient underwent surgery , and venous sinusoids and hematoma were found within the mass with defective temporal bones . the right fossa orbitalis , orbital plate , and lateral rectus muscle were involved , and the zygomatic arch and articulatio mandibularis were deformed . the solid part of tumor is consisted of spindle - like schwann cells , and the plexiform neurofibroma was pathologically confirmed after surgical procedure ( figure 2a - b ) . owing to the resection of the tumor , facial ptosis strikingly improved one month later , and the patient was then recovered step by step . ( a ) histology specimen demonstrates that the tumor is consisted of spindle - like schwann cells ( arrow ) ( he 200  ) , and ( b ) the area of hemorrhage in the mass ( * , he 100  ) . nf1 is the most common type of neurofibromatosis and usually presented with involvement of bone , nervous system , soft tissues and skin . pn is a special subtype of nf1 usually presented in childhood and 50% individuals have a positive family history as in the present case . malformation is a common feature due to invasive growth of the tumor , with hyper - pigmentation of the overlying involved skin . in the present case , pn which arises from cranio - maxillofacial region may involve the five sensory organs malformation is observed as well as a dysplastic cranium . the rapid increase of the pn size due to subacute hemorrhage within the tumor caused the loss of eyesight is extremely rare in our report . pn arises mainly from the peripheral nerves and represents a neoplasia of the nerve trunk or peripheral nerves and their nerve endings . the tumor consists of neuronal axons , schwann cells , fibroblasts and peripheral nerves with mucinous degeneration are predominant manifestations under electron microscope . pn consists of a proliferation of cells in the nerve sheath extending across the length of a nerve without a capsule and involving adjacent tissues . treatment of giant pn is typically surgical and complete resection is often difficult due to the extensive growth of the tumor and residual apartment may develop malignant change . non - enhanced ct scan demonstrated a giant heterogeneous attenuation mass with extensive involvement of both the superficial and deep tissue within cranio - maxillofacial region . mri displayed a heterogeneously hypo - intense to iso - intense mass on t1-weighted mri which was hyper - intense on t2-weighted images compatible with a cyst - like appearance with subacute hemorrhage and mucinous degeneration . both ct and mri can disclose the internal features of the tumor and the invasion of the surrounding tissues . in addition , the entire lesion can be clearly displayed in multiple planes using mri and three - dimensional ct . mri can effectively disclose the composition of the various soft tissues and the components of subacute hematoma such as hemosiderin . , we report a case of giant pn with hemorrhage in right cranio - maxillofacial region and its appearances on ct and mri . the images can display the internal features of the mass , and relationship between the three - dimensional structure of the lesion and the neighboring structures .
plexiform neurofibroma ( pn ) is a rare benign tumor and a special subtype of neurofibromatosis type 1 ( nf1 ) . 
 though the incidence is low , giant pn of the craniomaxillofacial region could result in severe hemifacial hypertrophy which is known as a typical manifestation of nf1 in young children . here 
 , we retrospectively reported a giant plexiform neurofibroma with hemorrhage in the cranio - maxillofacial region detected by ct and mri . 
 in addition , a brief review of the relevant literature is presented .