A radiological and histological comparison of two unusual adrenal incidentalomas

@#Introduction: The increasing use of radiological imaging studies has given rise to ‘incidentalomas’. Case Report: We describe two unusual and diverse incidental adrenal gland lesions, an adenomatoid nodule and a mature ganglioneuroma. Both are deemed ‘indeterminate’ on radiological assessment. On histology, an adenomatoid nodule is composed of variably-dilated thin-walled cysts lined by bland flattened cells and solid areas of tubules lined by eosinophilic cells with plump nuclei and prominent nucleoli. The lining cells are immunoreactive for calretinin and WT1 while negative for CK5/6, ERG and CD31. Mature ganglioneuroma features fascicles of bland spindle cells with intermixed mature ganglion cells disposed within a background myxoid stroma with no immature neuroblastic component. These spindled Schwann cells are S100 positive. Discussion: Both adenomatoid nodule and mature ganglioneuroma are rare benign adrenal tumours that need to be differentiated from other, more common adrenal lesions. The management of adrenal incidentalomas is challenging. Surgical excision is indicated if an adrenal incidentaloma is more than 4 cm in size, shows malignant features on imaging or evidence of hormone excess. Keywords:

Differential Diagnosis of Adrenal Mass Using Imaging Modality: Special Emphasis on F-18 Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography/Computed Tomography

Adrenal incidentalomas are adrenal masses serendipitously detected during an imaging study performed for reasons unrelated to suspicion of adrenal disease. The incidence of adrenal incidentalomas has increased because of the widespread use of various imaging modalities. In oncology patients with adrenal incidentalomas, the characterization of the adrenal masses is challenging because nearly 50% of incidental adrenal masses are metastatic lesions that need special medical attention. Although unenhanced computed tomography (CT) densitometry, chemical shift magnetic resonance imaging (MRI), delayed contrast-enhanced CT and CT histogram analysis have been used as sensitive and specific modalities for differentiating benign from malignant adrenal masses, F-18 fluoro-2-deoxy-D-glucose positron emission tomography (F-18 FDG PET)/CT is a highly accurate imaging modality compared to CT or MRI, especially when these two imaging modalities are combined. In addition, a semiquantitative analysis using standardized uptake value ratio further improves the diagnostic accuracy of F-18 FDG PET/CT in differentiating benign from malignant adrenal masses. Thus, F-18 FDG PET/CT is very helpful for determining the best therapeutic management, especially for assessing the need for surgery.

Clinical Characteristics and Metabolic Features of Patients with Adrenal Incidentalomas with or without Subclinical Cushing's Syndrome

BACKGROUND: The aim of this study was to examine the clinical characteristics of adrenal incidentalomas discovered by computed tomography (CT) and to investigate metabolic features of subclinical Cushing's syndrome (SCS) in patients with adrenal incidentalomas in a tertiary hospital in Korea. METHODS: This retrospective study examined the clinical aspects of 268 patients with adrenal incidentalomas discovered by CT at Soonchunhyang University Bucheon Hospital. Clinical data and endocrine function of the patients as well as histological findings were obtained from medical records, while anatomic characteristics were analyzed by reviewing imaging studies. Hormonal tests for pheochromocytoma, Cushing's syndrome, and aldosterone-secreting adenoma were performed. RESULTS: Most (n=218, 81.3%) cases were nonfunctioning tumors. Of the 50 patients with functioning tumors (18.7%), 19 (7.1%) were diagnosed with SCS, nine (3.4%) with overt Cushing's syndrome, 12 (4.5%) with primary aldosteronism, and 10 (3.7%) with pheochromocytoma. Malignant tumors (both primary and metastatic) were rare (n=2, 0.7%). Body mass index, fasting glucose, hemoglobin A1c, and total cholesterol were significantly higher in patients with SCS in comparison with those with nonfunctioning tumors. The prevalence of type 2 diabetes mellitus and hypertension were significantly higher in patients with SCS compared with those with nonfunctioning tumors. CONCLUSION: Functioning tumors, especially those with subclinical cortisol excess, are commonly found in patients with adrenal incidentalomas, although malignancy is rare. In addition, patients with SCS in adrenal incidentalomas have adverse metabolic and cardiovascular profiles.