Case Report: Diagnostic value of spectral CT in primary adrenal lymphoma.

Primary adrenal lymphoma (PAL) is a rare extranodal malignant tumor that poses significant diagnostic challenges due to its nonspecific clinical and imaging features. We report a case of unilateral PAL in a 55-year-old female presenting with flank pain and a hypodense adrenal mass. The lesion was characterized using dual-layer spectral detector computed tomography (CT) with analyses including virtual monoenergetic imaging, iodine density mapping, effective atomic number (Z-eff) calculation, and spectral attenuation curve evaluation. The mass demonstrated low attenuation, reduced iodine concentration (0.38-0.69 mg/mL), low Z-eff values (7.51-7.71), and a flat spectral curve pattern-findings consistent with hypovascular lymphoid tissue. Subsequent 18F-FDG PET/CT confirmed intense focal metabolic activity in the adrenal lesion (SUV_max 14.3). Biopsy confirmed the diagnosis of diffuse large B-cell lymphoma (DLBCL), non-germinal center B-cell (non-GCB) subtype. Spectral CT facilitated early non-invasive diagnosis, enhanced lesion conspicuity, and guided appropriate biopsy. This case highlights its diagnostic utility. The present case demonstrates the potential diagnostic value of multi-parameter spectral CT in differentiating PAL from other adrenal masses. These preliminary findings suggest the possible clinical utility of this technique; however, its role requires further validation through large-scale studies in the future.