An Atypical Finding in a Patient With Acute Left Flank Pain.

Hemorrhagic adrenal infarction is a rare and potentially under-recognized cause of acute flank pain. We report the case of a 29-year-old woman presenting with acute left flank pain of two days' duration. Initial contrast-enhanced abdominal CT, including unenhanced and portal venous phases, was interpreted as normal. Retrospective review demonstrated subtle enlargement of the left adrenal gland with mildly reduced enhancement compared with the contralateral gland. Following clinical deterioration with fever, a repeat CT performed five days later showed marked enlargement of the left adrenal gland with absent enhancement and surrounding periadrenal fat stranding, consistent with hemorrhagic adrenal infarction. MRI confirmed heterogeneous signal intensity, diffusion restriction, and lack of post-contrast enhancement, supporting the diagnosis. Laboratory evaluation revealed severe primary hypothyroidism consistent with autoimmune thyroiditis and heterozygous hemoglobin S (sickle cell trait). Endocrine assessment showed preserved adrenal function without evidence of adrenal insufficiency. Initial thrombophilia testing demonstrated abnormalities in coagulation factors interpreted in the context of an acute inflammatory state, and was considered non-contributory on hematology review. The patient was managed conservatively following multidisciplinary discussion, without anticoagulation, and showed favorable clinical and radiological evolution. This case highlights an important imaging pitfall: early unilateral adrenal infarction may present with subtle CT findings and can be missed on initial interpretation. Careful adrenal evaluation and short-interval follow-up imaging are essential in patients with persistent or worsening acute flank pain despite an initially negative CT.