Adrenal Masses, Incidentalomas, and Retroperitoneal Tumors — WACS Viva & Clinical Scenarios (Genitourinary and Retroperitoneal Imaging)

Exam-style adrenal masses, incidentalomas, and retroperitoneal tumors viva scenarios with examiner probes and model answers for Radiology candidates.

Scenarios covered

• SCENARIO 1: A 54-year-old hypertensive female undergoes a multiphasic CT abdomen for vague abdominal pain. An incidental 2.8 cm left adrenal nodule is identified. The unenhanced attenuation is 24 Hounsfield Units (HU). On dynamic post-contrast imaging at 60 seconds, the attenuation rises to 95 HU, and on 15-minute delayed imaging, the attenuation drops to 45 HU. Detail the diagnostic calculation required, provide the definitive diagnosis, and explain the physiologic basis of this phenomenon.
• SCENARIO 2: A 42-year-old male presents with episodes of paroxysmal headache, palpitations, and severe hypertension. Abdominal MRI demonstrates a 4.5 cm solid and cystic right suprarenal mass that exhibits marked hyperintensity on T2-weighted images ('lightbulb' sign) and intense, heterogeneous enhancement on post-gadolinium sequences without signal drop on opposed-phase chemical shift imaging. What is the most likely diagnosis, which nuclear medicine imaging modality is indicated for whole-body staging, and what critical clinical precaution must precede any invasive diagnostic intervention?
• SCENARIO 3: A 63-year-old male presents with early satiety and a palpable right flank mass. Abdominopelvic CT reveals a 14 cm retroperitoneal mass containing predominant macroscopic fat interspersed with thick, nodular, enhancing soft-tissue septa displacing the right kidney anteriorly and crossing the midline. Outline the systematic radiological approach to establish the compartment of origin, specify the most probable pathological diagnosis, and list the key staging features essential for surgical resection planning.
• SCENARIO 4: An asymptomatic 58-year-old male with a history of treated non-small cell lung carcinoma undergoes surveillance CT, which demonstrates an uncharacterized 3.2 cm right adrenal mass with an unenhanced attenuation of 32 HU. Out-of-phase chemical shift MRI demonstrates no signal loss relative to in-phase imaging. Delayed CT washout demonstrates an Absolute Percentage Washout (APW) of 34% and a Relative Percentage Washout (RPW) of 22%. Formulate the differential diagnosis, state the definitive imaging interpretation, and evaluate the role and safety requirements of percutaneous image-guided biopsy.
• SCENARIO 5: A 50-year-old female presents with bilateral flank aching, lower extremity edema, and renal insufficiency. Contrast-enhanced CT demonstrates a confluent, ill-defined soft-tissue mantle enveloping the infrarenal abdominal aorta and inferior vena cava, causing medial deviation and entrapment of both mid-ureters with upstream hydronephrosis. The aorta is not displaced anteriorly off the vertebral bodies. Differentiate this condition from malignant retroperitoneal lymphoma or nodal metastasis, and identify its systemic disease association.