[A benign adrenal schwannoma]

Adrenal schwannoma: why should endocrinologists be aware of this uncommon tumour?

PURPOSE

Adrenal schwannomas (AS) are rare tumours arising from Schwann cells. Due to the high prevalence of adrenal incidentalomas, running into very rare adrenal tumours has become a possibility for high volume expert centres. So far, the clinical behaviour and the radiological characteristics of AS make the pre-operative diagnosis of AS extremely challenging. Due to limited information available, we wanted to summarise the main features of this tumours, in order to raise the profile of an uncommon disease.

METHODS

We performed a MEDLINE and EMBASE research to review the literature. We found 57 case reports and case series and a total of 169 cases, including 2 more cases found in our Institutions. We collected data regarding year of publication, sex, age, and, when available, clinical presentation, hormonal data, radiological features, tumour site and size, treatment, histology and follow-up.

RESULTS

We analysed and discussed the clinical, radiological and pathological characteristics of cases identified, underlying the critical aspects of assessment and management of these tumours which still remain questioned, as, currently, pathologic examination is the only way to make the diagnosis.

CONCLUSIONS

The pre-operative diagnosis of AS is more than challenging and pathologic examination is so far the only way to make a certain diagnosis. Therefore, it is important to consider also the AS in the list of possible diagnoses when faced with a large not secreting adrenal tumour, with suspicious radiological features.

A case series of two cases of juxta-adrenal schwannoma presenting as adrenal mass lesion and review of the literature

Schwannomas are rare tumors in the retroperitoneal location. They can pose a diagnostic dilemma when presenting as an adrenal mass lesion due to their imaging characteristics. We report two cases of juxta-adrenal schwannomas presenting as symptomatic adrenal mass lesions. In both the cases, the clinical examination and functional evaluation was unremarkable and the radiological examination revealed a mixed intense adrenal mass lesion in one case with predominantly hyperintense areas and a very hyperintense lesion in another, in T2-weighted images, mimicking a adrenocortical malignancy and a pheochromocytoma respectively. Both cases were treated by surgical excision. Histopathological examination established the correct diagnosis of schwannoma, which was confirmed by immunohistochemical staining. Juxta-adrenal schwannoma is rare tumors of the retroperitoneum, which should also be borne in mind whenever encountering large nonsecreting adrenal tumors. We report a unique imaging characteristic, which helps in preoperative identification these rare lesions.

Adrenal schwannoma: a rare type of adrenal incidentaloma

Adrenal schwannoma is a rare type of adrenal incidentaloma, an adrenal lesion found incidentally, usually on imaging or autopsy. Computed tomography and magnetic resonance imaging are tools used to evaluate adrenal lesions. The diagnosis of adrenal schwannoma, however, cannot be made on imaging alone. Surgical resection is the primary means of management of adrenal schwannomas, as it is not possible to distinguish the schwannoma from malignant entities simply based on imaging. Histopathologic features of adrenal schwannomas are similar to those of schwannomas found at other sites. Conventional schwannomas, consisting of alternating Antoni A and Antoni B areas as well as Verocay bodies, have distinct microscopic features and can be readily distinguished from other entities. Cellular schwannomas, on the other hand, consist only of intersecting fascicles of spindle cells or Antoni A areas, resulting in a wide differential diagnosis. Ancillary studies such as immunohistochemical analysis and electron microscopy can help to provide a specific diagnosis.

Adrenal schwannoma treated with laparoscopic adrenalectomy: a case report

Schwannoma of the adrenal gland is extremely rare. Here, we report a 49-year-old patient with an adrenal tumor noted incidentally by abdominal ultrasonography while undergoing regular health examination. Retroperitoneal laparoscopic adrenalectomy was performed and the schwannoma was diagnosed by histologic findings and immunohistochemistry. Five months after surgery, the patient remained well and without evidence of recurrence or metastasis.

Schwannomas of the left adrenal gland and posterior mediastinum

Schwannoma is a rare tumor of neural crest cell origin. Most schwannomas occur in the head, neck, stomach or limbs, with a few cases occurring in the retroperitoneal space. A 30-year-old Taiwanese woman presented with a 1-week history of left anterior chest discomfort and left flank pain. The laboratory findings and endocrine studies were all within normal limits. Chest X-ray revealed masses in the posterior mediastinum. Chest computed tomography and magnetic resonance imaging showed several masses in the left paraspinal region and in the left adrenal region. The patient underwent total excision of the left paraspinal tumors and laparoscopic left adrenalectomy. Pathologic studies showed a picture of benign schwannoma. In conclusion, preoperative differentiation of benign schwannoma from malignant peripheral nerve sheath tumor or other tumors is important for good prognosis. Total excision of benign schwannoma is associated with favourable outcome in patients.

Schwannoma of the Adrenal Gland

Primary schwannomas of the adrenal gland are extremely uncommon. We report the clinical and pathologic features of two cases, occurring in a 73-year-old man and a 26-year-old woman, both of whom presented with abdominal pain and an adrenal mass on imaging studies. Both tumors were characterized by a proliferation of cytologically bland spindle cells. One case exhibited alternating compact Antoni A areas and less cellular Antoni B areas consistent with conventional schwannoma, whereas the other case was hypercellular and composed predominantly of Antoni A areas consistent with cellular schwannoma. Reactive inflammatory cells and lymphoid aggregates were present throughout both tumors. The diagnosis of schwannoma was supported by positive immunoreactivity for S-100 protein and collagen IV and absence of reactivity for keratin, muscle related antigens, and CD34 in both cases. Electron microscopy was also performed in the case of cellular schwannoma, which showed ultrastructural features confirming the diagnosis. Both cases had a favorable outcome without evidence of recurrence or metastasis. Because of its rarity, schwannoma occurring at this particular site can pose problems in diagnosis and should be distinguished from other spindle cell lesions of the adrenal gland.