it is caused by trauma , stress , sepsis , adrenal tumors , anticoagulation , hemorrhagic disorders and pregnancy .
idiopathic adrenal hematoma. the symptoms vary from subclinical to clinical , such as nausea , abdominal pain , fever and hypotension due to circulatory collapse .
adrenal tumors associated with hemorrhage primarily include pheochromocytomas , adrenocortical cancers and metastatic lesions from other organs . from a clinical perspective
, whether the lesion is benign or malignant is an important issue but is difficult to determine prior to surgery .
a 59-year - old japanese man was referred to our hospital for evaluation of a 7.0 cm mass in the posterior segment of the liver or right adrenal gland in november 2009 .
this mass was discovered when abdominal ultrasonography was obtained to evaluate a weight loss of 8 kg from may to november 2009 .
his body temperature was 37.0c , his blood pressure was 124/73 mm hg , and his pulse was regular at 67/min .
hormonal examination revealed a slightly elevated metanephrine level ( 0.35 mg / day ; normal range 0.040.19 ) .
tumor marker levels , including serum -fetoprotein , carcinoembryonic antigen and carbohydrate antigen 19 - 9 were all within normal ranges . only pivka - ii was slightly elevated at 53 mau / ml ( normal < 37 ) .
abdominal computed tomography ( ct ) demonstrated a well - demarcated , 7.0 cm lesion in either the posterior segment of the liver or in the right adrenal gland .
the peripheral region was slightly enhanced and the central part was hypovascular , indicating central necrosis ( fig .
there was no evidence of lymph node enlargement or distant metastasis . on magnetic resonance imaging ( mri ) ,
, the mass showed arterial enhancement and a ct filling defect in the right superior and inferior adrenal arteries and arterial portography , respectively ( fig .
i - meta - iodo - benzylguanidine ( mibg ) scintigraphy demonstrated no aberrant accumulation in the mass , which ruled out the possibility of a pheochromocytoma .
for the purposes of securing a definite diagnosis and treatment , an open right adrenalectomy was planned for march 2010 .
the resected specimen was 7.0  5.5 cm in size , and the cut surface of the mass was heterogeneous and dark red and white in appearance ( fig .
hematoxylin - eosin staining revealed hemorrhage , necrosis and hemosiderin deposit with normal adrenal tissue .
the patient had an uneventful postoperative course and was discharged home on postoperative day 12 .
small adrenal branches from the three main adrenal arteries form a subcapsular plexus , and the gland is drained by relatively few venules .
for example , stress increases adrenal vascularity and increases adrenal venous pressure due to vasoconstriction , resulting in intraglandular hemorrhage .
idiopathic adrenal hematomas are difficult to diagnose prior to surgery . in japan , koizumi et al .   described 14 cases of idiopathic adrenal hematomas from 1983 to 2010 .
of these 14 cases , 13 had been suspected to be adrenal tumors including malignant lesions preoperatively , but were then found to be  idiopathic adrenal hematomas on pathological examination after surgery . only 1 patient was diagnosed with an idiopathic adrenal hematoma without surgery .
the adrenal hemorrhage was not suspected to be caused by an adrenal tumor on the basis of ct , hormonal assay and mibg results , and this mass spontaneously regressed after 2 weeks .
although imaging modalities such as ct and mri are helpful in detecting adrenal hemorrhage , it is difficult to determine whether the hemorrhage is associated with tumors or not .
adrenal hemorrhage associated with pheochromocytoma ( 48% ) was the most frequently observed situation , and the second most frequently observed was a malignant lesion ( 20% ) such as adrenocortical cancer or metastasis from another organ .
hematomas derived from pseudocysts or adenomas comprised 17% of all cases . therefore , even if pheochromocytoma is ruled out by hormonal evaluations and imaging studies , the possibility that the mass may be a malignant lesion remains approximately 50% .
furthermore , the size of adrenal incidentalomas , which are adrenal gland masses discovered serendipitously on imaging , is an important factor in differentiating benign tumors from malignant lesions .
nieman   recommended routine surgical resection for adrenal incidentalomas > 4 cm in diameter without a clear - cut diagnosis . in our case , metastatic liver tumors , hemorrhaged hepatic cellular carcinoma with central necrosis and adrenal tumor were raised as differential diagnoses at the time of the initial consultation because of ring enhancement with hypovascularity on enhanced ct and a slightly elevated pivka - ii level .
subsequently , abdominal angiography revealed the origin of the mass to be the right adrenal gland .
although vital signs , laboratory data and mibg scintigraphy ruled out the possibility of a pheochromocytoma , the possibility of another malignancy could not be completely ruled out .
therefore , surgery was strongly recommended for a definite diagnosis as well as for treatment .
the reason for the patient 's weight loss and the increase in the pivka - ii in our case was not clear , but may have been related to exhaustion during the summer season from may until november that kept him from eating sufficiently .
in fact , his weight loss ceased after he consulted our hospital , and the pivka - ii value also normalized prior to surgery . in conclusion , we report herein a case of idiopathic adrenal hematoma .
an accurate diagnosis of idiopathic adrenal hemorrhage is quite difficult to make prior to surgery .
some imaging modalities are useful in generating a differential diagnosis , but if the potential for malignancy is not excluded , surgical resection should be taken into consideration .
 we report herein a case of idiopathic adrenal hematoma . 
 a 59-year - old japanese man was referred to our hospital for evaluation of a 7.0 cm mass in the right upper abdominal cavity . 
 the tumor was suspected to originate from either the posterior segment of the liver or the right adrenal gland . 
 his chief complaint was weight loss of 8 kg over the previous 6 months . 
 he had no past medical history and took no medications , including no anticoagulants . 
 laboratory data were almost normal except for a slight elevation of pivka - ii . 
 the origin of the tumor was found to be the adrenal gland , as angiography revealed the blood supply to the mass to derive from the right superior and inferior adrenal arteries . 
 a fine needle biopsy of the lesion was unable to confirm the diagnosis . 
 open right adrenalectomy was performed . 
 the histopathological findings of the surgical specimen revealed a hematoma with normal adrenal tissue . in the absence of any obvious etiology , the diagnosis was idiopathic adrenal hematoma . 