Adrenal schwannoma: CT and MRI findings

An unusual finding after adrenal surgery: a case series of adrenal schwannomas

Adrenal schwannomas are rare benign tumors with no specific imaging and laboratory findings to diagnose preoperatively. Due to the limited number of cases in the literature, clinical, imaging, and pathological findings are presented in this study. Case 1 is a 61-year-old woman patient who has a 31-mm mass in the right adrenal gland. This mass was nonfunctional; in imaging studies, this mass had a cystic necrotic component, and high 18-fluorodeoxyglucose (FDG) uptake was seen. There was no metaiodobenzylguanidine (MIBG) uptake. Laparoscopic transabdominal right adrenalectomy was performed, and the pathology result was consistent with adrenal schwannomas. Case 2 is a 63-year-old man patient who presented with a 38-mm mass in the left adrenal gland. This mass was nonfunctional and similar to that in Case 1; this mass had a cystic component. Laparoscopic transabdominal left adrenalectomy was performed. The diagnosis of adrenal schwannoma with degeneration was revealed. Case 3 was a 72-year-old woman patient admitted to the hospital for a 125-mm left adrenal mass. Similar to Case 1, this mass also had a cystic necrotic component in imaging studies. High FDG uptake was seen, and the patient underwent conventional adrenalectomy due to the suspicion of malignancy. After pathological evaluation, a diagnosis of adrenal schwannoma was made. A main diagnostic challenge in adrenal schwannomas is the preoperative diagnosis. These masses have no pathognomonic finding or specific hormonal function. Imaging findings of these masses may increase the suspicion of malignancy, which may affect decisions for surgery and the surgical technique.

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.

Benign adrenal and suprarenal retroperitoneal schwannomas can mimic aggressive adrenal malignancies: case report and review of the literature

The suprarenal retroperitoneum and adrenal gland is a rare site of origin for benign schwannomas which frequently present as larger and more aggressive lesions than schwannomas identified elsewhere. These tumors are often surgically excised. We present a case of an 81-year-old asymptomatic man presenting with an incidental 10 cm left suprarenal retroperitoneal mass identified on CT. The mass was indiscernible from the adrenal gland, demonstrating heterogeneous enhancement with a centrally cystic/necrotic core, and punctate calcifications. Subsequent core needle biopsy demonstrated a benign adrenal schwannoma. The lesion has been managed conservatively with imaging follow up and without complication. DISCUSSION: Our review of the literature identifies 121 reported in vivo benign adrenal and suprarenal schwannomas published to date with imaging features available for 90 cases (74%). All cases were encapsulated with the average size measuring over 6.5 cm. Fifteen percent (13/84) of reported lesions measured over 10 cm at presentation. Punctate calcification was present in 50% (26/52) of reporting cases. Nearly 50% (40/86) of cases demonstrate cystic/necrotic appearances on imaging. Despite aggressive appearances, our case demonstrates that biopsy and surveillance may represent a reasonable alternative to surgery in suboptimal surgical candidates.

Adrenal schwannoma in a female patient; A rare benign neoplasm: Case report and literature review

INTRODUCTION

Schwannomas are rare, slow-growing, usually benign tumors that originate from myelin-producing Schwann cells. Adrenal schwannomas are an exceptionally rare subset of these tumors, with few cases reported in the literature.

PRESENTATION OF CASE

We present the case of a 44-year old female patient being evaluated for chronic abdominal pain at the outpatient clinic. Clinical and laboratory workup was unremarkable. An abdominal CT scan was performed, revealing a left suprarenal solid mass (5 × 6 cm). Surgical resection of the adrenal gland was performed, given the patient's symptoms, the size of the tumor, and its malignant potential. The patient completed the postoperative period satisfactorily, and her symptoms improved. Histopathological findings were compatible with a benign adrenal schwannoma.

DISCUSSION

Schwannomas generally appear in the head, neck and extremities, with the vestibulocochlear nerve being the most frequently involved site. Retroperitoneal schwannomas account for 1-5% of retroperitoneal masses and comprise only 1-3% of all schwannomas. Their incidence increases with age, from 4% in the general population, reaching 7% in patients over 70 years of age.

CONCLUSION

Adrenal incidentalomas represent a diagnostic challenge. Because of the malignant potential of large (> 4 cm) adrenal masses and the lack of characteristic findings using conventional imaging techniques and laboratory diagnostic tools, surgical excision with histopathology and immunohistochemistry analysis are required for definitive diagnosis and optimal management.

Adrenal schwannoma: a case report

Retroperitoneum is an uncommon site for Schwannoma tumors and among adrenal incidentaloma the Schwannoma is rare. This condition lacks of a specific clinical and radiological features, but correct diagnosis before pathological examination should be very important for clinical management and surgical decision. We describe a case of voluminous retroperitoneal incidental mass, that was proved to be an adrenal Schwannoma.

Schwannoma Misdiagnosed as Adrenal Adenoma: A Case Report and Review of the Literature

Schwannoma is a benign neurogenic tumor originating from the neural sheath of Schwann cells. It is an extremely rare cause of adrenal adenoma which is very difficult to diagnose preoperatively. We report the case of a right adrenal schwannoma discovered incidentally in a 62-year-old woman during evaluation of right flank pain. The biochemical and hormonal evaluations were unremarkable. Radiological examination revealed a 4.8 cm lesion keeping with right adrenal adenoma. Surgical intervention was done due to the large size of the tumor, and laparoscopic right adrenalectomy was performed. The postoperative course was uneventful. Histological examination established the diagnosis of schwannoma, which was further confirmed by immunohistochemical staining. In conclusion, adrenal schwannoma is extremely rare and can be misdiagnosed as nonsecreting adrenal adenoma. Complete surgical excision is the treatment of choice which is associated with favorable outcome and also helps in clarifying its histopathological nature.

Sonographic appearances of adrenal schwannomas

OBJECTIVE

To evaluate the sonographic ultrasound (US) appearances of adrenal gland schwannomas.

MATERIALS AND METHODS

This was a retrospective analysis of 15 cases of schwannomas involving the adrenal gland. The following US features were assessed: size, border, echogenicity, homogeneity, intralesional cystic necrosis, presence of septa, intralesional calcification, posterior acoustic enhancement and blood supply.

RESULTS

Of the 15 tumors, seven (46.7%) were located on the left side, and the remaining eight (53.3%) on the right side. The most frequent US appearance of adrenal schwannoma was a single, well-defined and isoechoic mass. The internal echotexture was homogeneous in 2 cases, and heterogeneous in 13 cases, with intralesional cystic areas (n = 11), septa (n = 10) or calcifications (n = 6). Posterior acoustic enhancement was seen in 12 of the 15 cases (80%). On color Doppler US, 86.7% (13/15) of the lesions did not show any vascularity.

CONCLUSIONS

Adrenal schwannomas usually present on US as well-defined isoechoic masses often with posterior acoustic enhancement, cystic necrosis with septa and poor blood supply. These appearances should suggest the diagnosis of adrenal schwannomas. Nevertheless, additional information from laboratory tests and CT or MR imaging may be required to avoid unnecessary surgery.

Retroperitoneal malignant schwannoma in a child

Retroperitoneal malignant schwannomas are extremely rare. Only a few cases have been reported, only one of which occurred in a child. We herein report a case of retroperitoneal malignant schwannoma in a 2-year-old boy who presented with a painless mass in the right lumbar region. The mass had gradually enlarged during a 1-year period, and it was about the size of the patient's fist at the time of consultation. Whole-abdomen computed tomography revealed a space-occupying lesion in the retroperitoneum infiltrating from the L1 to L4 spinal canal. A preoperative diagnosis of a retroperitoneal tumor was made, and complete tumorectomy was performed. Postoperative pathological examination showed a malignant schwannoma. The tumor recurred 1 month after the first operation, and a second complete excision was carried out; the postoperative pathologic examination findings were similar to the previous findings. The patient recovered well and continued to undergo close follow-up.

Adrenal Schwannoma Treated with Open Adrenalectomy: a Case Report

Adrenal schwannomas are very rare tumors accounting for only 0.2% of the adrenal tumors. These are very difficult to diagnose preoperatively and usually present as incidental non-secreting adrenal masses in asymptomatic patients or in patients with non-specific complaints. Computed tomography (CT) and magnetic resonance imaging (MRI) are required to aid the diagnosis, but adrenal schwannomas cannot be distinguishably confirmed on the basis of imaging alone. Histopathological examination (HPE) is essential for accurate diagnosis. We report a rare case of a right adrenal schwannoma in a 68-year-old man. The clinical evaluation was unremarkable and the radiological examination revealed a suprarenal mass lesion on ultrasonography (USG). CT revealed a right adrenal mass which was purported to be likely malignant. Right adrenalectomy was performed by the open approach along with excision of the surrounding enlarged lymph nodes. The postoperative course was uneventful. HPE established the adrenal mass to be a schwannoma, a benign tumor arising from Schwann cells, an exceedingly unusual occurrence in the adrenal glands. A non-secreting adrenal mass can be easily misjudged and the exact diagnosis of the lesion cannot be made sure of without both radiologic and pathologic confirmation. Unilateral adrenal primary or metastatic lesions need pathological confirmation as it can dramatically affect prognosis. Unusual tumors of the adrenal gland like schwannomas may be found incidentally or otherwise and will generate difficulties in establishing the right management. Complete excision is the treatment of choice whenever feasible and will also clarify pathology.

Abdominal schwannomas: review of imaging findings and pathology

Schwannomas are typically slow growing, encapsulated benign neoplasms. Visceral schwannomas are rare, and preoperative diagnosis is challenging, as they are often confused with other neoplasms even with advanced imaging studies. Surgical excision is usually needed to establish a definitive diagnosis, as pathology is the "gold standard." We review the imaging findings of abdominal schwannomas focusing on pancreatic, gastrointestinal, and retroperitoneal/adrenal schwannomas with pathology correlation. We conclude that schwannoma should be included in the broad differential diagnosis of an abdominal mass and that when it is unnecessary radical resection can be avoided.

Adrenal Schwannoma: A Rare Incidentaloma

Adrenal schwannomas are very rare tumours that are difficult to diagnose preoperatively. A 42-year-old male presented with epigastric pain and indigestion. He had history of repeated operations for recurrent facial swelling on both sides of face diagnosed as Angiolymphoid Hyperplasia with Eosinophilia (ALHE). Physical examination revealed right facial swelling. Laboratory tests showed no evidence of hormonal hypersecretion. CECT abdomen showed a well-defined heterogenously enhancing right adrenal mass (5x4cm). Patient underwent right adrenalectomy. Histopathology revealed adrenal schwannoma, confirmed by immunohistochemistry (IHC) showing diffuse expression of S-100. Fine-needle aspiration biopsy of facial lesion confirmed ALHE recurrence. Less than 35 cases have been reported. Diagnosis of adrenal schwannoma on imaging studies is very difficult and surgical resection when performed for non-functioning adrenal masses >4cm clinches the diagnosis. Adrenal schwannoma is highly uncommon and was incidentally associated with recurrent ALHE.

Imaging of rare medullary adrenal tumours in adults

Although adrenal medullary tumours are rare, they have important clinical implications. They form a heterogeneous group of tumours, ranging from benign, non-secretory, incidental masses to hormonally active tumours presenting acutely, or malignant tumours with disseminated disease and a poor prognosis. Increasingly, benign masses are incidentally detected due to the widespread use of imaging and routine medical check-ups. This review aims to illustrate the multimodality imaging appearances of rare adrenal medullary tumours, excluding the more common phaeochromocytomas, with clues to the diagnosis and to summarise relevant epidemiological and clinical data. Careful correlation of clinical presentation, hormone profile, and various imaging techniques narrow the differential diagnosis. Image-guided percutaneous adrenal biopsy can provide a definitive diagnosis, allowing for conservative management in selected cases. A close collaboration between the radiologist, endocrinologist, and surgeon is of the utmost importance in the management of these tumours.

Myxoid adrenocortical adenoma: magnetic resonance imaging and pathology correlation

We report a case of a 74-year-old female with myxoid adrenocortical adenoma which showed different magnetic resonance imaging findings compared to those of a typical adrenocortical adenoma. The myxoid change in the adrenocortical adenoma is a rare form of degeneration. It presents a considerable diagnostic challenge to both radiologists and clinicians because it can mimic other adrenal tumor types on imaging. The MRI findings of the presented case included a high signal intensity on T2-weighted images similar to that of fluid and delayed progressive enhancement.

A rare adrenal incidentaloma: adrenal schwannoma

Adrenal schwannoma is an extremely uncommon cause of incidentaloma. It originates from neural sheath Schwann cells of the adrenal gland. We report the case of a left adrenal schwannoma incidentally discovered in a 32-year-old woman during examination of bloated feeling and stomach ache. The patient was incidentally found to have a left adrenal mass of 9 cm on abdominal ultrasonography. Computed tomography (CT) of the abdomen and [¹⁸F] fluorodeoxyglucose positron emission tomography (PET) were also performed. Metabolic evaluation was unremarkable. Due to the large size of the tumor, left adrenalectomy was performed. The postoperative course was uneventful. Histological examination established the diagnosis of schwannoma. This diagnosis was supported by immunohistochemistry of S-100 and vimentin positivity. In conclusion, adrenal schwannoma is an extremely rare entity and can grow considerably in size. The present case report emphasizes that clinicians should be aware of the possibility of retroperitoneal schwannoma. Total excision of benign schwannoma is associated with a favorable outcome. To our knowledge, there are case reports of schwannoma with CT and magnetic resonance imaging findings in the literature, although this is the first schwannoma case with PET-CT imaging.

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.

Retroperitoneal schwannomas

Background:

Retroperitoneal schwannomas are very rare and are usually found incidentally.

Cases Report:

Two rare cases of retroperitoneal schwannomas are reported. Both were incidentally found during US scans for non-specific epigastric pain and were initially diagnosed as non-secreting retroperitoneal tumors. The diagnosis was confirmed by CT scan. In both patients the tumors were resected. The definitive diagnosis was possible by histopathology.

Conclusions:

Although the preoperative assessment of a retroperitoneal tumor may be indicative of a retroperitoneal schwannoma, the definitive diagnosis is possible only by histopathology after surgical removal of the tumor.

Three uncommon adrenal incidentalomas: a 13-year surgical pathology review

BACKGROUND

The discovery of adrenal incidentalomas due to the widespread use of sophisticated abdominal imaging techniques has resulted in an increasing trend of adrenal gland specimens being received in the pathology laboratory. In this context, we encountered three uncommon adrenal incidentalomas.The aim of this manuscript is to report in detail the three index cases of adrenal incidentalomas in the context of a 13-year retrospective surgical pathology review.

METHODS

The three index cases were investigated and analyzed in detail with relevant review of the English literature as available in PubMed and Medline. A 13-year retrospective computer-based histopathological surgical review was conducted in our laboratory and the results were analyzed in the context of evidence-based literature on adrenal incidentalomas.

RESULTS

A total of 94 adrenal specimens from incidentalomas were identified, accounting for 0.025% of all surgical pathology cases. In all 76.6% were benign and 23.4% were malignant. A total of 53 females (56.4%) and 41 males (43.6%) aged 4 to 85 years were identified. The benign lesions included cortical adenoma (43.1%), pheochromocytoma (29.3%) and inflammation/fibrosis/hemorrhage (8.3%). Metastatic neoplasms were the most common malignant lesions (50%) followed by primary adrenocortical carcinomas (31.8%) and neuroblastoma (13.6%). These cases were discovered as adrenal incidentalomas that led to surgical exploration.The three index cases of adrenal incidentalomas with unusual pathologies were encountered that included (a) adrenal ganglioneuroma, (b) periadrenal schwannoma and (c) primary adrenal pleomorphic leiomyosarcoma. These cases are discussed, with a literature and clinicopathological review.

CONCLUSIONS

Adrenal lesions are uncommon surgical specimens in the pathology laboratory. However, higher detection rates of adrenal incidentalomas aided by the ease of laparoscopic adrenalectomy has resulted in increased adrenal surgical specimens leading to unsuspected diagnostic and management dilemmas. Accurate pathological identification of common and uncommon adrenal incidentalomas is essential for optimal patient management.

Experience with adrenal schwannoma in a Chinese population of six patients

OBJECTIVES

Benign adrenal schwannoma is an extremely uncommon cause of incidentaloma. This article describes our experience with the diagnosis and treatment of adrenal schwannoma in a Chinese population of 6 patients. To our knowledge, this is the largest series of this uncommon adrenal tumor treated in a single center.

METHODS

From May 1999 to May 2009, 6 patients with incidentally discovered adrenal schwannoma were operated on at a tertiary referral hospital in Eastern China. Clinical details, radiographic features, laboratory examinations, pathological findings, and follow-up data of these patients were analyzed.

RESULTS

Of the 6 patients, 4 were females (F) and 2 were males (M), with a mean age of 40.5 yr (range: 30-47, M:F=2:1). The 6 patients were managed with open unilateral adrenalectomy; 5 patients had schwannomas on the left side, and 1 on right side. Abnormal urine catecholamine was detected in 1 patient. The mean pathological size of these tumors was 4.3 ± 1.1 cm. The diagnosis of schwannoma was based on classic histological findings, and supported by immunohistochemistry of S-100, vimentin, and ABC positivity. In the follow- up of 47.5 ± 32.3 months, no recurrence and metastasis were observed.

CONCLUSIONS

Although there may be some clues for radiological diagnosis of adrenal schwannoma, preoperative misdiagnosis is not infrequent. Those tumors may occasionally have endocrine function. Histological examination is the key of diagnosis, and surgical resection is the treatment of choice once malignancy cannot be excluded by preoperative analyses.

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.