Image of the month Neutrophilic urticaria: whole-body 111 In-leukocyte scan and histological correlation Prakash Manoharan 1 , Douglas Fullen 2 , Anca Avram 1 1 Nuclear Medicine, University of Michigan, 1500 E. Medical Center Drive, Ann Arbor, MI 48109-0028, USA 2 Pathology, University of Michigan, Ann Arbor, MI 48109-0028, USA Received: 15 April 2006 / Accepted: 7 May 2006 / Published online: 5 September 2006 © Springer-Verlag 2006 Eur J Nucl Med Mol Imaging (2006) 33:1523–1524 DOI 10.1007/s00259-006-0202-7 An 88-year-old male who had recently undergone abdom- inal aortic aneurysm repair was admitted for assessment of a possible aorto-enteric fistula. In addition, he had recently been diagnosed with a parotid abscess and had started to take oral antibiotics. CT scan did not detect an aorto-enteric fistula but did reveal a small amount of fluid in the pelvis and inflammatory changes around the aortic graft. There was clinical concern regarding graft infection, and a 111 In- labeled white cell scan was requested (a,b). This revealed diffuse abnormal radiotracer uptake within the subcutane- ous tissue (arrows), predominantly of the arms, pelvis, and legs. There was no abnormal increased activity in the region of the aorta to suggest graft infection. The patient had also developed a widespread cutaneous rash 3 days post initiation of antibiotic therapy, described as non-blanchable, pink, erythematous, non-scaly urticarial plaques; some plaques were annular while others were in a geographic configuration. A punch biopsy of skin was performed, with hematoxylin and eosin staining. At low power, a dermal inflammatory infiltrate (arrows) was observed, associated with prominent edema (c). At high magnification, the inflammatory infiltrate was seen to be composed predominantly of neutrophils (arrows) without leukocytoclasis or vessel wall damage (d). Occasional eosinophils were present. These histologic features were most in keeping with a neutrophilic urticaria or urticarial hypersensitivity reaction in the clinical setting of urticarial plaques with a geographic configuration. The histologic differential diagnosis included an early neutrophilic der- matosis, such as Sweet’ s syndrome, or an acute infection. The patient was treated with diphenhydramine hydro- chloride and the antibiotics were changed. The rash settled. He was discharged with no further sequelae. Neutrophilic urticaria is a subtype of urticaria character- ized by the diapedesis of neutrophils, resulting in a predominantly neutrophilic dermal infiltrate. The neutro- Prakash Manoharan ()) Nuclear Medicine, University of Michigan, 1500 E. Medical Center Drive, Ann Arbor, MI 48109-0028, USA e-mail: prakashmanoharan@yahoo.co.uk Tel.: +1-734-9362435, Fax: +1-734-9368181 European Journal of Nuclear Medicine and Molecular Imaging Vol. 33, No. 12, December 2006