Radiological differentiation of phaeochromocytoma from other malignant adrenal masses: importance of wash-in characteristics on multiphase CECT

Abstract

Rationale and introduction To evaluate the computerised tomography (CT) characteristics of phaeochromocytoma (PCC) that differentiate them from other non-benign adrenal masses such as adrenocortical carcinoma (ACC), primary adrenal lymphoma (PAL) and adrenal metastases (AM). Methods This retrospective study was conducted at a tertiary health care institute from Western India. Patients presented between January 2013 and August 2016 with histological diagnosis of PCC or other non-benign adrenal mass having adequate reviewable imaging data comprising all four CECT phases were included. Results The study cohort consisted of 72 adrenal masses from 66 patients (33 PCC, 22 ACC, 4 PAL, 13 AM). Unlike other masses, majority of PCC (25/33) showed peak enhancement in early arterial phase (EAP). PCC had significantly higher attenuation in EAP and early venous phase (EVP), and higher calculated percentage arterial enhancement (PAE) and percentage venous enhancement (PVE) than other adrenal masses (P < 0.001). For diagnosis of PCC with 100% specificity, PAE value ≥100% and EAP attenuation ≥100 HU had 78.8 and 63.6% sensitivity respectively. ACC were significantly larger in size as compared to PCC and metastasis. The adreniform shape was exclusively found in PAL (two out of four) and AM (4 out of 13). None of the enhancement, wash-in or washout characteristics were discriminatory among ACC, PAL and AM. Conclusion Peak enhancement in EAP, PAE value ≥100% and EAP attenuation ≥100 HU differentiate PCC from other malignant adrenal masses with high specificity.

The Utility of 68Ga-DOTATATE PET/CT in Localizing Primary/Metastatic Pheochromocytoma and Paraganglioma: Asian Indian Experience

“…Moreover, adrenal adenomas, especially those with poor washout, may closely mimic cluster 2-related PCC on CECT. [ 19 ] These imaging pitfalls may rarely pose an important diagnostic challenge.…”

“…[ 15 16 17 ] Metastasis was defined as the presence of tumor cells at sites that normally lack chromaffin tissue,[ 15 16 17 ] and was further classified based on the diagnosis of metastasis at or within 3 months (synchronous) or after 3 months (metachronous) of the diagnosis and resection of the primary tumor. [ 18 ] CECT was done using the protocol as described in previous study,[ 18 19 ] 68 Ga-DOTATATE PET/CT, 18 F-FDG PET/CT, and 131 I-MIBG scintigraphy were done as described in these studies. [ 20 21 ]…”

Diagnostic performance of adrenal CT in the differentiation of adenoma and pheochromocytoma

“…Further studies investigated AP enhancement of pheochromocytomas and found AP more helpful than other phases (16,17). Northcutt et al.…”

Clinical Spectrum of Adrenal Cushing’s Syndrome and the Caution for Interpretation of Adrenocorticotrophic Hormone: A Single-Center Experience

“…Plasma ACTH level was repeated in patients with borderline plasma ACTH (10-20 pg/ml). Contrast-enhanced CT adrenal imaging was performed with a 64-slice multidetector CT system (Brilliance 64, Philips Healthcare, Best, and The Netherlands), and absolute and relative washout characteristics of adrenal masses were noted as per standard protocol [12]. 18 F-Fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET/CT) was performed as per standard protocol for patients with suspected malignancy.…”