intravascular papillary endothelial hyperplasia ( ipeh ) is a benign , non - specific , vascular lesion consisting of reactive proliferation of the endothelial cells that arise in organizing thrombus16 ) . ipeh is most commonly located in the skin or subcutaneous tissue , where it exhibits a benign clinical course , but has also occurred in many locations across the body . on ct imaging , there is little differentiating ipeh from eosinophilic granuloma and other skull tumors , but gadolinium - enhanced mri scans are useful in demonstrating the extremely vascular and hyperdense nature of ipeh4,10 ) . however , there are no specific radiological features that characterize ipeh ; hence , it is usually diagnosed after being treated surgically as another mass lesion , unless there is initially a high index of suspicion of the tumor . we present the characteristic clinical , radiological , and pathological findings in a case of ipeh involving the calvarium . a 10-year - old female patient , who was otherwise healthy , presented with a palpable mass on her right frontal skull , which had been present for 1 month . , we observed a firm , painful , fixed mass of about 1.5 cm in diameter involving the right frontal bone . a routine skull x - ray showed a 1.2 cm sized punch - out lesion on the right frontal bone , without bone expansion or sclerosis ( fig . computed tomography demonstrated a well - demarcated punch - out lesion with a transdiploic , exophytic soft tissue mass on the frontal scalp . magnetic resonance ( mr ) imaging disclosed the presence of a 1.31.21 cm nodular mass ( fig . 2 ) . this mass lesion was hypointense on t1 and heterogeneous hyperintense on t2 weighted mr images , and exhibited inhomogeneous enhancement of the soft tissue filling the punch - out lesion after intravenous administration of gadolinium . the skull lesion was completely removed , along with a wide margin , and a cranioplasty was performed . gross examination of the specimen revealed a friable , brown colored lesion in the bone . microscopic examination revealed some proliferation of epithelioid cells with hemorrhage and fibrin clots ( fig . in the center of the lesion , there were vague papillary configurations of epithelioid cells admixed with hemorrhage and fibrious materials . the epithelioid cells had slightly irregular nuclei with a vesicular chromatin pattern , and occasional distinctive nucleoli ( fig . 3c ) and vimentin , a weekly positive for cd34 and ck , and negative for d2 - 40 , ema , lca , s-100 , hmb-45 , cd21 , cd68 , cd3 and cd20 . ipeh was considered a form of endothelial proliferation , and was usually located in the skin or subcutis of the neck and extremities . although there is ongoing discussion as to the pathogenesis of ipeh , today most authors consider this lesion to be an unusual form of thrombus organization with exuberant proliferation5,6,18 ) . the tumor - like growth may be induced by disturbed local hemodynamics that induce progression of thrombus formation and the subsequent development and growth of ipeh4 ) . ipeh can be divided into three different categories : the pure form that occurs within a dilated vascular space , which is most frequently located in the finger , head and neck or in the region between the elbows and hands ; the mixed form that appears as a focal change in a hemangioma , vascular malformation , or pyogenic granuloma ; and the undetermined form , belonging to neither of the first two categories , which has an extravascular origin6,12,14 ) . extracranial ipeh usually presents as a slow - growing nodule that may be tender and somewhat painful . the age at manifestation varies widely , and there seems to be a slight female predominance in patients . at surgery although ipeh most commonly occurs in skin and subcutaneous soft tissue , it has been reported in a variety of locations , including the liver , uterus , and gastrointestinal tract2,6 ) . it appears , however , to have a predilection for the head and hands3 ) . there were no specific radiological features of ipeh , where similar radiological findings can also be seen in other lesions such as eosinophilic granuloma , aneurysmal bone cyst , medullary fibrosarcoma , hemangioma , and metastatic tumors from the thyroid or kidney . most skull tumors share certain mri characteristics , such as hypointensity on t1-weighted images , hyperintensity on t2-weighted images , and some degree of contrast enhancement . histologically , the lesion consists of an intravascular proliferation of numerous papillae that are composed of a core of connective tissue and an endothelial surface . however , also having features of malignancy , such as nuclear pleomorphism , it often presents mitotic figures , necrosis , multiple layers of endothelial cells , and infiltrating growth into adjacent structures . immunohistochemically , ipeh reacts with factor viii , cd31 , cd34 , corresponding to the endothelial cells being the proliferative component3,11,14,15 ) . vimentin has been previously reported to be positive in the stroma of these tumors as it was in our case . ipeh has known to act aggressively , in that it generally recurs when incompletely resected2,9 ) . therefore , the mainstay of therapy for intracranial ipeh has been , where possible , complete surgical resection . complete resection was possible in the present case because of the small size and favorable location of the mass . adjuvant radiotherapy or chemotherapy for incompletely resected or multiple intracranial lesions has been associated with both lesion stabilization and short - term regression2,7,14 ) . given the small number of cases reported , it is difficult to draw any conclusions based on the efficacy of adjuvant therapy . we believe that total excision of the ipeh should be done before the mass reaches a size that might make complete removal impossible or cause other complications . ipeh of the skull is a rare benign tumor located on the skull . due to its rarity , ipeh is often misdiagnosed radiologically . these lesions may grow rapidly and reach an enormous size , and generally recur if incompletely resected . therefore , we recommend that ipeh of the skull should be treated by complete resection with a wide margin to prevent a recurrence .
a 10-year - old female patient presented with a rapidly growing nodular mass lesion on her right frontal area . on skull radiography and computed tomography ( ct ) imaging , this mass had a well - demarcated punch - out lesion with a transdiploic , exophytic soft tissue mass nodule on the frontal scalp . 
 magnetic resonance ( mr ) imaging revealed the presence of a 1.51.21 cm sized calvarial lesion . 
 this lesion was hypointense on t1 and heterogenous hyperintense on t2 weighted mr images , and exhibited heterogeneous enhancement of the soft tissue filling the punch - out lesion after intravenous administration of gadolinium . 
 en block removal of the tumor with resection of the rim of the normal bone was performed . 
 the pathological diagnosis was intravascular papillary endothelial hyperplasia ( ipeh ) . 
 after surgery , no recurrence was found for 8 months . 
 ipeh is a rare and benign reactive lesion usually found in thrombosed subcutaneous blood vessels . 
 involvement of skull bone is rare . in this article , we present a case of ipeh involving the calvarium , in a 10-year - old woman .