Dark ring sign: finding in patients with fungal liver lesions and transfusional hemosiderosis undergoing treatment with antifungal antibiotics.
OBJECTIVE
To describe the MR appearance of necrotizing fungal granulomas occurring in the liver of leukemic patients with hepatosplenic fungal disease and transfusional hemosiderosis on antifungal antibiotics.


METHODS
Four patients with acute myelogenous leukemia (n = 2) or acute lymphocytic leukemia (n = 2) who developed hepatosplenic fungal disease, and were treated with antifungal medication, underwent MRI examination on a 1.5 T MR imager. MR images were prospectively evaluated and correlated with liver biopsy (three patients), and clinical picture (one patient).


RESULTS
Multiple liver lesions measuring approximately 1 cm in diameter were identified in all patients. Lesions possessed a distinctive MR appearance: central mild hyperintensity with a peripheral ring of very low signal intensity on precontrast T1- and T2-weighted images. The central region of the lesions enhanced following gadolinium administration with the peripheral ring remaining low in signal intensity.


CONCLUSIONS
Necrotizing fungal granulomas in the liver of patients with transfusional hemosiderosis on treatment with antifungal antibiotics have a distinctive appearance of moderate high signal intensity center on T1- and T2-weighted and postgadolinium MR images with a peripheral rim of low signal intensity. This appearance reflects the presence of iron-laden macrophages in the periphery of granulomas and may be expected in processes that initiate an immune response involving aggregation of macrophages in the liver of patients with transfusional iron overload.
Department of Radiology, University of North Carolina at Chapel Hill 27599-7510, USA.
N L
NL
Kelekis
R C
RC
Semelka
H J
HJ
Jeon
A S
AS
Sallah
T C
TC
Shea
J T
JT
Woosley
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000666:Amphotericin B / Q000627:therapeutic use; D000935:Antifungal Agents / Q000627:therapeutic use*; D002177:Candidiasis / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy / Q000473:pathology; D002648:Child; D005260:Female; D006099:Granuloma / Q000175:diagnosis; D006486:Hemosiderosis / Q000150:complications* / Q000209:etiology; D006801:Humans; D017964:Itraconazole / Q000627:therapeutic use; D007938:Leukemia / Q000150:complications; D008099:Liver / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D009894:Opportunistic Infections / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy / Q000473:pathology; D065227:Transfusion Reaction
D000935:Antifungal Agents; D017964:Itraconazole; D000666:Amphotericin B