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Year : 2021  |  Volume : 64  |  Issue : 2  |  Page : 379-381
Adrenal schwannoma: An uncommon incidentaloma

1 Department of Pathology, IPGME and R, Kolkata, West Bengal, India
2 Department of Urology, IPGME and R, Kolkata, West Bengal, India

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Date of Submission10-May-2020
Date of Decision17-Jun-2020
Date of Acceptance01-Aug-2020
Date of Web Publication9-Apr-2021


WHO classification of adrenal tumors. Only a handful of cases have been reported so far. A 30-year-old lady presented with cerebrovascular accident. CT scans of the abdomen and pelvis revealed a 3.5-cm well-defined, smooth margined, heterogeneously enhancing, mass lesion in the right adrenal gland. She had no endocrine symptoms and urinary metanephnines were normal. She underwent right adrenalectomy for incidentaloma. Histopathology of the excised mass showed features of an adrenal schwannoma. Diagnosis of adrenal schwannoma on imaging studies is difficult preoperatively and raises suspicion of other adrenal tumors. Surgical excision followed by histopathology confirms the diagnosis.

Keywords: Adrenal schwannoma, adrenal tumors, incidentaloma

How to cite this article:
Bhattacharya S, Kumar A, Chatterjee U, Pal DK. Adrenal schwannoma: An uncommon incidentaloma. Indian J Pathol Microbiol 2021;64:379-81

How to cite this URL:
Bhattacharya S, Kumar A, Chatterjee U, Pal DK. Adrenal schwannoma: An uncommon incidentaloma. Indian J Pathol Microbiol [serial online] 2021 [cited 2021 May 16];64:379-81. Available from: https://www.ijpmonline.org/text.asp?2021/64/2/379/313258

   Introduction Top

Adrenal schwannoma is an uncommon adrenal medullary tumor, recently included in the World Health Organization (WHO) classification of adrenal tumors. Only a handful of cases have been reported so far.[1] With improved imaging techniques, there has been a substantial rise in the number of adrenal masses discovered incidentally, and they are labeled as “Incidentalomas.”[2] Here we report a case of an adrenal schwannoma, discovered incidentally on routine imaging of the abdomen in a young lady who presented with cerebrovascular accident. It was surgically removed and diagnosed to be an adrenal schwannoma.

   Case Report Top

A 30-year-old lady presented with cerebrovascular accident. As a part of the diagnostic evaluation, a CT scan of the abdomen and pelvis was done. It revealed a 3.5-cm, well-defined, smooth margined, heterogeneously enhancing, soft tissue nodule in the right adrenal gland [Figure 1]a. A metabolic workup was done which included serum cortisol, urinary metanephrine, and vanillylmandelic acid (VMA) levels. All of these were within normal range. A standard transperitoneal laparoscopic adrenalectomy was performed with no complications. Postoperative pathologic evaluation revealed a 4 × 3 × 1-cm adrenal gland bearing a pale cream, well-circumscribed, firm mass measuring 3 cm across [Figure 1]b. Histopathological examination showed features of a typical schwannoma, composed of bland spindle cells arranged in a sort organoid pattern with plentiful Verocay bodies. Areas of hyalinization, fibrosis, and focal lymphocytic infiltration were present. There were no neuroblasts or ganglion cells (mature, immature, or maturing) present. The entire tissue was processed. On immunostaining, the tumor cells were uniformly positive for S-100 (clone 15E2E2, Biogenex). No neuronal cells were picked up with chromogranin (clone LK2H10, Cell Marque) [Figure 2]. The antibodies were prediluted, ready to use, and the immunostaining was done manually. A diagnosis of adrenal schwanomma was made on this incidentaloma. Her postoperative period was uneventful.
Figure 1: (a) CT scan abdomen reveals an adrenal mass on the right side (arrow). (b) Cut section of adrenal reveals a pale cream, well-circumscribed tumor

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Figure 2: (a) Scan power view of the tumor showing rim of adrenal cortical tissue in the upper part of the field and the tumor in the lower half of the field (40×). (b) Low-power view showing fascicles of bland spindle cells along with foamy cells (100×). (c) High magnification showing spindle cells with wavy nuclei, loose stroma, and hyalinized vessels (400×). (d) Immunohistochemical staining for S-100 showing diffuse positivity (400×)

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   Discussion Top

With extensive usage of modern imaging modalities, the detection rate of adrenal pathology has increased a great deal. These are called “incidentalomas,” which means a clinically and hormonally asymptomatic lesion, detected by chance during imaging. The prevalence of adrenal incidentaloma increases from 3% in middle age to 10% in the elderly.[2],[3] Amongst these incidentalomas, the majority are small, nonsecretory lesions and most of them turn out to be adenomas on histological examination. Here, we present a case of incidentally discovered adrenal schwannoma along with its possible differentials.

The fourth edition of the 2017 WHO classification of endocrine tumors introduced “adrenal schwannoma” under mesenchymal and stromal tumors of adrenal gland for the first time. Only a handful of cases of adrenal schwannoma have been reported described so far.[1] Morphologically schwannomas originating from adrenal glands share similar features as schwannomas elsewhere. It is thought that adrenal schwannomas originate from Schwann cells that insulate the nerve fibers innervating the adrenal medulla. It is more common in women. Till now, association of this tumor with neurofibromatosis has not been reported.[1]

Adrenal schwannomas are typically incidental finding; however, patients may present with clinical symptoms related to the mass effect of the tumor.[1],[4],[5] On computed tomography, schwannoma appears as a well-demarcated, round, or oval mass that may be heterogenous; however, the radiological features are not diagnostic. Histomorphological examination alone provides definitive diagnosis.

Although the histological diagnosis of adrenal schwannoma is generally straightforward, it still needs to be differentiated from other more common adrenal lesions. Adrenal adenoma, the commonest cause of incidentaloma, is morphologically different. The rare spindle cell variant of adreno-cortical tumor shows condiderable pleomorphism and is immunopositive for SF-1 and inhibin. Mophologically, the closest differential is ganglioneuroma, also a medullary tumor with a common ancestry from the neural crest.[6],[7] They represent the most differentiated end of the spectrum of neuroblastic tumors, that is, neuroblastoma, ganglioneuroblastoma, and ganglioneuroma. The stroma of ganglioneuroma is composed of loosely arranged spindle-shaped cells intermixed with mature and maturing ganglion cells with abundant eosinophilic cytoplasm, large vesicular nuclei, and prominent nucleoli. The stroma is loose and resembles neurofibroma more than schwannoma. Verocay bodies, typical of schwannoma, are not seen. Lymphocytic infiltration is quite common in neuroblastic tumors. Immunohistochemistry for synaptophysin, chromogranin, neuron-specific enolase, and CD56 highlights the ganglion cells and neuroblastic cells. Therefore, adequate sampling is important to rule the differentiated neuroblastic tumors, with far and few scattered ganglion cells.

Other rare spindle cell lesions of the adrenal gland are leiomyoma and solitary fibrous tumor.[1] These spindle cell lesions are uncommon and can easily be differentiated from schwannoma by morphological examination and immunohistochemistry. Leiomyoma shows an orderly pattern of intersecting fascicles of deeply acidophilic cells with blunt-ended nuclei without significant cellular pleomorphism or mitotic activity. Leiomyomas with nuclear palisading can be distinguished from schwannomas in that the former has significant amount of cytoplasmic glycogen, cytoplasmic fuchsinophilia, and longitudinal striations. Tumor cells in leiomyoma are positive for desmin and caldesmon. Solitary fibrous tumor is characterized by haphazard arrangement of spindle cells with areas of hyalinization and expresses CD34 and STAT6.

Another close morphological differential is the rarely reported “sustentaculoma” of the adrenal medulla, composed of bland, mitotically inactive, spindle cells. This tumor shares a similar immunohistochemical profile with schwannoma. It is distinguished morphologically by the lack of typical histologic features of schwannoma including Antoni A and B growth patterns, Verocay bodies, and thick-walled blood vessels.[8]

Rarely adrenal schwannoma can be part of composite adrenal medullary tumors, coexisting with a pheochromocytoma.[9],[10] These composite tumors include combination of pheochromocytoma with a component of neuroblastoma, ganglioneuroblastoma, ganglioneuroma, schwannoma, sustentaculoma, or malignant peripheral nerve sheath tumor. However, despite the entire tissue being processed, no second component was detected in our case.

   Conclusion Top

Here, we report a case of an incidentally discovered adrenal schwannoma. Being an incidental finding and of nonsecretory nature, it raises suspicion of other common adrenal primary and metastatic tumors. Histological examination alone establishes definitive diagnosis.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Lloyd RV, Osamura RY, Kloppel G, Rosai J. WHO Classification of Tumours: Pathology and Genetics of Tumours of Endocrine Organs. Lyon: IARC; 2017. p. 176.  Back to cited text no. 1
Grumbach MM, Biller BM, Braunstein GD, Campbell KK, Carney JA, Godley PA, et al. Management of the clinically inapparent adrenal mass (“incidentaloma”). Ann Intern Med 2003;138:424-9.  Back to cited text no. 2
Mansmann G, Lau J, Balk E, Rothberg M, Miyachi Y, Bornstein SR. The clinically inapparent adrenal mass: Update in diagnosis and management. Endocr Rev 2004;25:309-40.  Back to cited text no. 3
Lau SK, Spagnolo DV, Weiss LM. Schwannoma of the adrenal gland: Report of two cases. Am J Surg Pathol 2006;30:630-4.  Back to cited text no. 4
Korets R, Berkenblit R, Ghavamian R. Incidentally discovered adrenal schwannoma. JSLS 2007:113-5.  Back to cited text no. 5
Maweja S, Materene R, Detrembleur N, Leval L, Defechereux T, Meurisse M, et al. Adrenal ganglioneuroma. Am J Surg 2007;194:683-4.  Back to cited text no. 6
Zografos GN, Kothonidis K, Ageli C, Kopanakis N, Dimitriou K, Papaliodi E, et al. Laparoscopic resection of large adrenal ganglioneuroma. JSLS 2007;11:487-92.  Back to cited text no. 7
Lau SK, Romansky SG, Weiss LM. Sustentaculoma: Report of a case of a distinctive neoplasm of the adrenal medulla. Am J Surg Pathol 2006;30:268-73.  Back to cited text no. 8
Lam KY, Lo CY. Composite pheochromocytoma-ganglioneuroma of the adrenal gland: An uncommon entity with distinctive clinicopathologic features. Endocr Pathol 1999;10:343-52.  Back to cited text no. 9
Menon S, Mahajan P, Desai SB. Composite adrenal medullary tumor: A rare cause of hypertension in a young male. Urol Ann 2011;3:36-8.  Back to cited text no. 10
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Correspondence Address:
Uttara Chatterjee
Department of Pathology, Institute of Post Graduate Medical Education and Research, Kolkata - 700 020, West Bengal
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJPM.IJPM_526_20

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