we report a case of left adrenal schwannoma in a 62-year - old man , incidentally discovered on an abdominal computed tomography .
on admission , no remarkable findings were recognized in the patient 's blood and urine examination , including adrenal function .
macroscopically , the tumor ( 45 mm  30 mm , 60 g ) arose from the medulla of the adrenal gland with a clear border distinguishing it from surrounding tissues .
although an increasing number of adrenal incidentaloma have been identified with the recent advances in imaging techniques , only a few cases of schwannoma of the adrenal gland have been reported .
we reviewed the cases reported previously in an attempt to reveal the characteristic features of this rare disease .
schwannoma is a benign neurogenic tumor originating from schwann cells , which also produce the myelin sheath that covers peripheral nerves .
however , schwannoma arising from the adrenal gland is an extremely rare entity ; only 11 cases have been reported in the literature .
herein , we report a case of adrenal schwannoma , successfully treated with laparoscopic adrenalectomy and review the cases previously reported in an attempt to clarify the characteristic features of this rare disease .
a 62-year - old man was referred to our hospital for further examination and treatment of his incidentaloma of the left adrenal gland .
a local physician diagnosed the patient with mild liver dysfunction , and the patient had undergone an abdominal computed tomography as part of his workup .
a round mass with a maximum diameter of 40 mm was recognized on the left adrenal gland . on admission ,
no physical features were present to suggest cushing 's syndrome or von recklinghausen 's disease .
magnetic resonance imaging ( mri ) revealed a round mass 40 mm in diameter in the patient 's left adrenal gland .
the mass had a clear border setting it off from surrounding structures , and a portion of the mass had a lobular surface .
the mass had low - signal intensity on a t1-weighted image and demonstrated slightly heterogeneous high - signal intensity on a t2-weighted image ( figure 1 ) .
endocrinological examinations revealed no remarkable findings to suggest a functioning adrenal tumor ( table 1 ) .
although acth was slightly elevated , it was thought to be nonspecific , because no alterations in either the morning level or the daily rhythm of cortisol secretion was observed .
the diagnosis was made of a nonfunctioning left adrenal tumor . because of the size and partly irregular shape of the mass , a laparoscopic transabdominal left adrenalectomy was performed to rule out a malignant tumor .
the mass registered low - signal intensity on the t1-weighted image ( a ) , and a slightly heterogeneously high - signal intensity on the t2-weighted image ( b ) .
endocrinological data on admission while under general anesthesia , the patient was placed in a right hemi - lateral position with a pillow under the right lower limb to lift up the left flank .
an 11-mm trocar for a laparoscope was introduced by the open method at the level of 5 cm cranial to the navel on the left midclavicular line . after investigating the abdominal cavity to confirm no abnormal tumors , ascites , or adhesions , a 12-mm trocar for a vessel sealing system and 10-mm trocar for forceps
were introduced under video vision at the left subcostal level on the anterior axillary line and on the median line , respectively .
the spleen was mobilized by cutting the lieno - renal ligament , and the mass was easily found between the pancreas tail and the left kidney , surrounded by fatty tissue ( figure 2 ) .
the tumor with the adrenal gland was carefully isolated with sharp or blunt dissection , with surrounding fatty tissue , by using a vessel - sealing system .
after the left adrenal vein was clipped and cut , preserving the left subphrenic vein , the isolated tumor was enclosed within an endoscopic pouch and was extracted via the extended wound of the 12-mm trocar . a clearly bordered round , firm mass was found within the left adrenal gland .
the operation time was 86 minutes , and the blood loss was 100 g. the 45 mm  30 mm  30 mm tumor was observed to have developed from the medulla of the adrenal gland and weighed 60 g ( figure 3 ) .
histologically , the tumor consisted of spindle cells without atypia or mitosis . a thin , fibrous area indistinctly separated the tumor from the surrounding nonatrophic adrenal cortex .
immunohistochemical analysis revealed that the tumor cells were uniformly positive for s-100 , and partly positive for myeline , but were negative for c - kit , smooth muscle actin , cd34 , and desmin .
abdominal ultrasonography confirmed no recurrent disease , and the patient is in good health without disease 36 months after surgery .
the tumor ( arrows ) was removed with left adrenal gland and surrounding fatty tissues .
macroscopic view of the tumor that arose from the adrenal medulla , compressing the normally developed cortex .
the majority of the tumors originating in the adrenal medulla are pheochromocytoma , neuroblastoma , or ganglioneuroma .
schwannoma of the adrenal gland is rarely encountered , although it similarly originates from the cells of the neural crest .
the origin of the adrenal schwannoma is considered to be either of 2 myelinized nerve systems innervated to the adrenal medulla .
one is the sympathetic nerve from the upper lumbar plexus , and the other is the phrenic or vagus nerve . all reported cases demonstrate that the schwannoma originated in the medulla ; no schwannoma has been reported to arise from the cortex .
this is likely the consequence of the nerve in the adrenal cortex developing quite poorly compared with that in the medulla and only a few thin nerves running along the vasculature .
the diagnosis of schwannoma of the adrenal gland was difficult to make based on the imaging studies .
typical mri findings report solid tumors with low - signal intensity on t1-weighted images and heterogeneously high - signal intensity on t2-weighted images , with occasional cystic components .
however , imaging findings were nonspecific for the tumors with a nerve origin , such as neuroblastoma or ganglioneuroma .
every reported case has been treated as a nonfunctioning incidentaloma of the adrenal gland , and the diagnosis of schwannoma was determined postoperatively through histological examination .
conventionally , schwannoma are divided into 2 distinct subtypes , hyper - cellular  antoni a  type and hypo - cellular  antoni b  type .
spindle cells are arranged in fascicles in areas of high cellularity with little stromal matrix in the antoni a type .
nuclear - free zones called  verocay bodies  can also be found in between the regions of nuclear palisading .
tumor cells are less densely found , forming loose meshwork often accompanied by microcysts or myxoid changes in antoni b type , and are considered to be a degenerated form of the antoni a type .
both sub - types can be found as a mixture in adrenal schwannoma ; 3 of 11 reported cases demonstrated both subtypes in a tumor .
the differential diagnosis made using immunostaining should exclude gastrointestinal stromal tumor ( gist ) or leiomyoma .
by contrast , gist is positive for c - kit , and leiomyoma is positive for smooth muscle actin .
eleven cases of adrenal schwannoma have been previously reported in english and japanese ( table 2 ) as far as we can determine from a search of pubmed and japana centro revuo medicina .
three patients experienced abdominal pain . the tumors in these 3 patients were large in size ( 75 mm , 90 mm , and 124 mm ) .
in addition , a histological demonstration of a large cystic tumor and 2 small tumors incidentally found in the autopsy samples have been reported . excluding these 5 cases , 7 adrenal schwannomas , including our case ,
were incidentally found by imaging analyses performed as a part of the workup for the nonspecific symptoms .
the size ranged from 28 mm to 90 mm ( average , 56 ) when identified , which was not considered large enough to cause clinical symptoms .
they were demonstrated to be large solid masses ( 60 mm and 180 mm ) extending over the adrenal gland occupying the retroperitoneum , and with unfavorable outcomes .
however , no case of catecholamine - secreting  benign  adrenal schwannoma has been reported . as in our case and
however , these elevations were considered nonspecific because no evidence was present of alteration in cortisol secretion in either case .
thus , features of adrenal schwannoma should be considered the same as so - called typical
 reported cases of adrenal schwannoma nd = not described ; us = abdominal ultrasonography ; ugi = upper gastrointestinal series ; ct : computed tomography
died of myocardial infarction no abnormal findings with either 123i - metaiodobenzylguanidine nor 131i-6b - iodomethyl-19-nor - cholest-5(10)-en-3b - ol scintigraphy , incidentally observed asymptomatic tumor in the adrenal gland , incidentaloma , has been increasing , along with the advance in the field of imaging technology .
these incidentalomas are most frequently cortical adenomas followed by carcinoma , pheochromocytoma , and myelolipoma .
when excluding these major tumors by hormonal and imaging analysis , adrenal schwannoma should be expected , although it has been extremely rare .
however , no well - established recommendation for surgical application has been developed for patients with tumors between 4 cm and 6 cm .
the consensus suggests that criteria in addition to size should be considered in making the decision to monitor or proceed to adrenalectomy .
relevant variables to perform laparoscopic adrenalectomy for incidentaloma have been proposed that include a low complication rate ( less than 3% ) and the informed consent .
the present case suggests that application of laparoscopic adrenalectomy to the incidentaloma could be a feasible choice , when performed by an experienced surgical team with appropriate informed consent , not only as a minimally invasive treatment , but also as a whole tumor biopsy to establish a correct diagnosis .
 objective : we report a case of left adrenal schwannoma in a 62-year - old man , incidentally discovered on an abdominal computed tomography . it was successfully treated with laparoscopic adrenalectomy.methods:on admission , no remarkable findings were recognized in the patient 's blood and urine examination , including adrenal function . 
 laparoscopic left adrenalectomy was performed with the diagnosis of a nonfunctioning adrenal tumor.results:macroscopically , the tumor ( 45 mm  30 mm , 60 g ) arose from the medulla of the adrenal gland with a clear border distinguishing it from surrounding tissues . 
 histologically , the tumor consisted uniformly of spindle cells that were positive for s-100 . 
 the cortex was compressed but showed no atrophy . 
 the diagnosis of adrenal schwannoma was made.conclusion:although an increasing number of adrenal incidentaloma have been identified with the recent advances in imaging techniques , only a few cases of schwannoma of the adrenal gland have been reported . 
 we reviewed the cases reported previously in an attempt to reveal the characteristic features of this rare disease . 
Objective:
Methods:
Results:
Conclusion:
INTRODUCTION
CASE REPORT
DISCUSSION
CONCLUSION