pituitary insufficiency in childhood is often secondary to pituitary or hypothalamic 
 space - occupying lesions . the differential diagnosis in etiologies of a mass in the sella is 
 broad in spectrum , including rathke s cyst , tumor , autoimmune diseases , primary or 
 metastatic neoplasms , and granulomatous inflammation . among them , xanthomatous pituitary 
 diseases are rare in childhood . these conditions include xanthomatous hypophysitis , 
 xanthogranulomatous hypophysitis and xanthogranuloma of the sellar region ( 1,2,3,4,5 ) . xanthogranuloma of the sellar region is characterized 
 by a granulomatous lesion containing cholesterol clefts , macrophages , chronic inflammatory 
 infiltrates , and hemosiderin deposit ( 6 ) . this 
 condition has been traditionally regarded as a hallmark of the adamantinomatous 
 craniopharyngioma even in the absence of epithelium ( 6 ) . however , paulus et al . ( 7 ) suggested that 
 xanthogranuloma is likely to constitute a different entity from the classical 
 adamantinomatous craniopharyngioma clinically and pathologically . after their original 
 report , several patients with xanthogranuloma of the sellar region have been described 
 ( 8 , 9 ) . 
 however , to our knowledge , there is no detailed clinical report of xanthogranuloma of the 
 sellar region in cases of pediatric age . here , we report the cases of two children with 
 xanthogranuloma of the sellar region , presenting central diabetes insipidus ( di ) . a 9-yr - old japanese boy was referred to our clinic because of a 6-mo history of polyuria 
 and polydipsia . his height was 135.3 
 cm ( + 0.7 sd ) and body weight 29.9 kg . the growth hormone ( gh ) releasing 
 hormone ( ghrh ) and the thyroid stimulating hormone releasing hormone ( trh ) tolerance tests 
 showed subnormal responses of gh and tsh , respectively ( table 1table 1 endocrinological findings of cases 1 and 2 ) . the corticotropin releasing hormone ( crh ) tolerance test showed normal 
 responses of acth and serum cortisol ( table 
 1 ) . magnetic resonance imaging ( mri ) the mass was hyperintense on the 
 t1-weighted ( a ) and in the t2-weighted images ( b ) . the pituitary stalk deviated 
 to the frontal direction and the anterior pituitary gland was compressed by the tumor . there was no calcification of the mass detected by computed tomgraphic ( ct ) scan . cyst was suspected preoperatively by the mri findings , however a definite diagnosis could 
 not be made . the capsule of the tumor 
 had tightly adhered to the dura of the sellar floor . histological examination of the tumor showed fibrous tissue with cholesterol 
 clefts , macrophages , multinucleated giant cells , and lymphocyte infiltration ( fig . ( b ) macrophages ( white arrowheads ) 
 and multinucleated giant cells ( black arrowheads ) were observed . postoperatively , di remains and has been treated with desmopessin 
 acetate ( ddavp ) . two months after surgery , gh and tsh responses after stimulation tests 
 recovered ( table 1 ) . after one - year follow - up , the patient continues to have di , but his basal 
 levels of igf-1 , ft3 , ft4 and tsh are within normal ranges .   radiological appearance on magnetic resonance imaging ( mri ) . the mass was hyperintense on the 
 t1-weighted ( a ) and in the t2-weighted images ( b ) . ( b ) macrophages ( white arrowheads ) 
 and multinucleated giant cells ( black arrowheads ) were observed . a 6-yr - old japanese boy was admitted to our hospital for evaluation of polyuria and 
 polydipsia of 6-mo duration . his 
 height was 113.2 cm ( 0.8 sd ) and body weight was 18.8 kg . brain mri showed an intrasellar mass , which was high on the t1-weighted ( fig . gadolinium 
 administration caused no enhancement of the mass . ) and hypointense on the t2-weighted images ( fig . ghrh , trh , and crh 
 tolerance tests showed normal responses one month after surgery ( table 1 ) . the patient is currently well only on ddavp 
 medication , 12 mo after surgery . a 9-yr - old japanese boy was referred to our clinic because of a 6-mo history of polyuria 
 and polydipsia . his height was 135.3 
 cm ( + 0.7 sd ) and body weight 29.9 kg . the growth hormone ( gh ) releasing 
 hormone ( ghrh ) and the thyroid stimulating hormone releasing hormone ( trh ) tolerance tests 
 showed subnormal responses of gh and tsh , respectively ( table 1table 1 endocrinological findings of cases 1 and 2 ) . the corticotropin releasing hormone ( crh ) tolerance test showed normal 
 responses of acth and serum cortisol ( table 
 1 ) . magnetic resonance imaging ( mri ) the mass was hyperintense on the 
 t1-weighted ( a ) and in the t2-weighted images ( b ) . the pituitary stalk deviated 
 to the frontal direction and the anterior pituitary gland was compressed by the tumor . there was no calcification of the mass detected by computed tomgraphic ( ct ) scan . cyst was suspected preoperatively by the mri findings , however a definite diagnosis could 
 not be made . the capsule of the tumor 
 had tightly adhered to the dura of the sellar floor . histological examination of the tumor showed fibrous tissue with cholesterol 
 clefts , macrophages , multinucleated giant cells , and lymphocyte infiltration ( fig . ( b ) macrophages ( white arrowheads ) 
 and multinucleated giant cells ( black arrowheads ) were observed . postoperatively , di remains and has been treated with desmopessin 
 acetate ( ddavp ) . two months after surgery , gh and tsh responses after stimulation tests 
 recovered ( table 1 ) . after one - year follow - up , the patient continues to have di , but his basal 
 levels of igf-1 , ft3 , ft4 and tsh are within normal ranges .   radiological appearance on magnetic resonance imaging ( mri ) . the mass was hyperintense on the 
 t1-weighted ( a ) and in the t2-weighted images ( b ) . ( b ) macrophages ( white arrowheads ) 
 and multinucleated giant cells ( black arrowheads ) were observed . a 6-yr - old japanese boy was admitted to our hospital for evaluation of polyuria and 
 polydipsia of 6-mo duration . his 
 height was 113.2 cm ( 0.8 sd ) and body weight was 18.8 kg . brain mri showed an intrasellar mass , which was high on the t1-weighted ( fig . . the mass had a high appearance on the t1-weighted 
 images ( a ) . gadolinium 
 administration caused no enhancement of the mass . ) and hypointense on the t2-weighted images ( fig . ghrh , trh , and crh 
 tolerance tests showed normal responses one month after surgery ( table 1 ) . the patient is currently well only on ddavp 
 medication , 12 mo after surgery . we report the cases of two children with xanthogranuloma in the pituitary region with di . xanthogranuloma in the sellar region has been traditionally considered to be a variant of 
 adamantinomatous craniopharyngioma despite the lack of epithelium ( 6 ) . however , paulus et al . ( 7 ) 
 reviewed histological sections of 110 patients diagnosed with craniopharyngioma and found 
 sections from 37 patients were exclusively or predominantly composed of xanthogranulomatous 
 tissue . according to their study , pathological findings were characterized by cholesterol 
 clefts ( 100% ) , macrophages infiltrates , lympho - plasmacelluar infiltrates ( 100% ) , marked 
 hemosiderin deposits ( 97% ) , fibrosis ( 87% ) , and foreign - body giant cells around cholesterol 
 clefts ( 86% ) . only sections from 3 of these patients had small adamantinomatous components 
 ( corresponding to calcifying odontogenic cyst ) , which are histological features of 
 adamantinomatous craniopharyngioma . based on these findings , paulus et al . suggested that 
 xanthogranuloma of the sellar region is pathologically distinct from adamantinomatous 
 craniopharyngioma . in our two patients , histological findings of cholesterol clefts , macrophages including cholesterol droplets , multinucleated giant cells , lymphocytes , and the 
 absence of adamantinomatous components are consistent with those previously reported by 
 paulus et al . clinically , xanthogranuloma in the sellar region has been reported to cause severe 
 endocrinological deficits ( 7 ) . ( 9 ) also described one adult japanese patient with 
 xanthogranuloma in the pituitary showing panhypopituitarism . by contrast , our patients did 
 not have severe defects of anterior pituitary hormones and showed only central di . in the 
 first report , xanthogranuloma of the pituitary in children was reported , but the frequency 
 in children , and the clinical and endocrinological findings were not mentioned ( 7 ) . to answer whether clinical manifestations of 
 xanthogranuloma in children are different from those of adults , more patients with 
 xanthogranuloma of pediatric age must be studied . if xanthogranuloma is different form adamantinomatous craniopharyingioma , what is the 
 origin of xanthogranuloma in the sellar region ? xanthogranulomatous inflammation ( also known 
 as cholesterol granuloma ) has been reported in various tissues such as the middle ear , 
 mastoid , and choroid plexus . also the obstruction of the gall 
 flow has been considered to cause inflammation , eventually developing to xanthogranulomatous 
 cholecystitis ( 11 ) . in addition , it is suggested that 
 rathke s cyst and neuroepithelial cyst may undergo xanthogranulomatous changes ( 12 , 13 ) . taken 
 together , xanthogranuloma of the sellar region is likely to represent a non - specific tissue 
 reaction to hemorrhage or degenerative changes originating from heterogeneous etiologies . it 
 may be plausible that xanthogranulomas of our patients were responses to ruptured cysts , 
 however , no confirmation of pre - existing cysts has been identified . xanthogranuloma is difficult to differentiate from craniopharyngioma and rathke s cyst by 
 mri findings . cystic 
 and solid lesions may have any pattern of signal intensity on the t1 and t2-weighted images , 
 although most often they are hypointense to isointense on the t1-weighted images and 
 hyperintense on the t2-weighted images . on ct , craniopharyngiomas typically appear as 
 moderate - to - large , partially calcified mass . rathke s cysts are present as intrasellar 
 masses . as with craniopharyngiomas , the signal characteristics are variable on the t1 and 
 t2-weighted images due to the variable quality of the cyst fluid . in our two patients , previously , two 
 reports have also described xanthogranuloma as hyperintense on t1-weighted images ( 8 , 9 ) . in addition , 
 there was no calcification of masses in our patients , as well as in previous reports ( 8 , 9 ) . these points 
 may be helpful in considering xanthogranuloma of the pituitary region . however , there is no 
 reliable way to distinguish xanthogranuloma from craniopharyngioma and rathke s cyst without 
 histological examination . in conclusion , currently , whether this condition is a truly distinct entity or merely a different 
 manifestation of adamantinomatous craniopharyingioma is unclear . to clarify the natural 
 history , pathogenesis and prognosis in childhood , further accumulation of well - characterized 
 pediatric cases with xanthogranuloma
we report the cases of two japanese children with cystic pituitary enlargement on 
 magnetic resonance imaging ( mri ) causing central diabetes insipidus ( di ) . in the first 
 patient , 
 endocrinological examination demonstrated slightly impaired growth hormone and 
 thyroid stimulating hormone secretions , but normal responses of other anterior pituitary 
 hormones . 
 the second patient had normal basal levels of anterior pituitary hormones . 
 transsphenoidal resection of the tumors was performed in both patients . 
 histological 
 analysis of the tumor sections demonstrated granulomatous tissue with cholesterol clefts , 
 foamy macrophages , multinucleated giant cells and no epithelial component . 
 thus , these 
 tumors were pathologically diagnosed as xanthogranuloma of the sellar region , different 
 from adamantinomatous craniopharyngioma . 
 post - operatively , the two patients continue to 
 have di , however other hormone replacement therapy after one year of follow - up has not 
 been required . 
 currently , it is not clear whether xanthogranuloma is a distinct entity 
 from adamantinomatous craniopharyingioma . although , to our knowledge , a clinical report of 
 xanthogranuloma of the sellar region has not been reported at pediatric age , it would be 
 included in the differential diagnosis of the sellar region .