Concentric-ring sign in adrenal hemorrhage

Excerpt

A 30-year-old man with back pain and hypertension with no history of trauma or coagulopathy was referred to our hospital. A subsequent surveillance CT scan of the abdomen showed enlargement of the left adrenal gland. Weighted MRI showed an isointense mass (Fig. 1a, white arrowhead) surrounded by an area of bleeding (Fig. 1a, black arrow) on T1-weighted imaging consistent with adrenal hematoma with partial rupture on arrival. Adrenal hormone levels and all tumor markers were within normal limits. Abnormal accumulation was not detected both in F-18 fluorodeoxyglucose positron emission tomography/computed tomography and ¹³¹I-metaiodobenzylguanidine scintigraphy. One month later, a unique MR appearance termed “concentric-ring sign” was seen, which appears as a mass lesion with a dark peripheral rim (Fig. 1b, black arrowhead) surrounding a bright ring (Fig. 1b, white arrowhead) on T1-weighted image. The center of the mass lesion appeared homogeneous with intensity slightly greater than muscle. Four months later, the patient’s adrenal gland showed marked reduction in size, and the concentric-ring sign had disappeared. This characteristic concentric-ring sign and the dynamic size change of the adrenal gland suggest idiopathic adrenal hemorrhage without neoplastic findings.

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