A rare case of lipomatous ganglioneuroma of the adrenal gland

Abstract

Lipomatous ganglioneuroma’s are exceedingly rare benign tumours. They originate from the neuroepithelium along the sympathetic ganglia. These rare tumours have been reported generally in the posterior mediastinum and retroperitoneum. We describe a case of a lipomatous ganglioneuroma in the adrenal gland. This case is unique as it has a lipid poor appearance on computed tomography with normal metabolic activity. To our knowledge this is the second case reported within the adrenal gland.

1 Introduction

Ganglioneuroma’s are benign tumours that originate from the neuroepithelium along the sympathetic ganglia. Lipomatous ganglioneuroma’s are an exceptionally rare variant that possess adipocytes in addition to Ganglion and Schwann Cells. Lipomatous ganglioneuroma’s have been described primarily in the posterior mediastinum and retroperitoneum. We describe a case of a lipomatous ganglioneuroma arising from the adrenal gland. To our knowledge this is only the second case of this documented, however this case differs with the patient having normal metabolic activity and lipid poor appearance of an adrenal lesion on Computed Tomography (CT).

2 Case report

A 28-year-old-male was referred from his General Practitioner for investigation following a finding of microhaematuria during a health check. He underwent a renal tract Ultrasound (US) which demonstrated a solid nodule adjacent to the right kidney. This prompted further work up for a suspected adrenal lesion.

The man’s 24-h urine catecholamines were all in normal range. His 24-h urine volume was elevated at 3.89 L. Dexamethasone suppression, DHEAS, 24-h cortisol test, plasma metanephrines, and renin-aldosterone assay were all within normal ranges and urine cytology was negative. CT adrenal glands showed a 51mm × 36mm lesion within the right adrenal gland, however enhancement characteristics were not consistent with benign disease. The hounsfield units (HU) were 33 HU for the pre-contrast, 42 HU for the 1-min delay and 58 HU for the 15 minutes delay phase (see Image 1). This is an absolute washout value of -178 % and a relative washout value of -38 % (absolute washout of less than 60 % is indeterminate and a relative washout of less than 40 % is indeterminate). Differentials included lipid poor adenoma or adrenocortical carcinoma. There were no other suspicious lesions on CT imaging of chest, abdomen, or pelvis.

A laparoscopic adrenalectomy was performed. There were no complications, and the man was discharged on day 2.(See Fig. 1,2 ) )

Pathological examination demonstrated lipomatous ganglioneuroma of the right adrenal gland, with clear margins. Macroscopically the lesion was firm, white in colour, and 65mm × 42mm x 38mm (see Image 2). Microscopic evaluation revealed that the lesion was comprised of nerve fibres arranged in sheets and fascicles in addition to ganglion cells both scattered and grouped together (see Image 3a and 3b). There were some foci of mature adipocytes (see Image 3c). The immunohistochemistry was positive for S-100 protein (see Image 3d), Synaptophysin (see Image 3e), NF, WT-1, and Glial Fibrillary Acidic Protein (GFAP). It was negative for Chromogranin and HMB 45.(See Fig. 3 a-3e)