Case Report IL-6-Producing, Noncatecholamines Secreting Pheochromocytoma Presenting as Fever of Unknown Origin Marco Ciacciarelli, 1 Davide Bellini, 2 Andrea Laghi, 2 Alessandro Polidoro, 1 Antonio Pacelli, 1 Anna Giulia Bottaccioli, 1 Giuseppina Palmaccio, 1 Federica Stefanelli, 1 Piera Clemenzi, 1 Luisa Carini, 1 Luigi Iuliano, 1 and Cesare Alessandri 1 1 Department of Medico-Surgical Sciences and Biotechnologies, Internal Medicine Unit, ICOT Hospital, “Sapienza” University of Rome, Via Franco Faggiana 34, 04100 Latina, Italy 2 Department of Radiological Sciences, Oncology and Pathology, ICOT Hospital, “Sapienza” University of Rome, Via Franco Faggiana 34, 04100 Latina, Italy Correspondence should be addressed to Marco Ciacciarelli; marco.ciacciarelli@uniroma1.it Received 25 January 2016; Revised 11 June 2016; Accepted 17 July 2016 Academic Editor: Christian Koch Copyright © 2016 Marco Ciacciarelli et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Fever of unknown origin (FUO) can be an unusual frst clinical manifestation of pheochromocytoma. Pheochromocytomas are tumors that may produce a variety of substances in addition to catecholamines. To date, several cases of IL-6-producing pheochromocytomas have been reported. Tis report describes a 45-year-old woman with pheochromocytoma who was admitted with FUO, normal blood pressure levels, microcytic and hypochromic anemia, thrombocytosis, hyperfbrinogenemia, hypoalbuminemia, and normal levels of urine and plasma metanephrines. Afer adrenalectomy, fever and all infammatory fndings disappeared. 1. Introduction Petersdorf and Beeson [1] developed criteria for prolonged fevers, that is, fever of unknown origin (FUO), defned as fever ≥38.3 ∘ C (101 ∘ F) for >3 weeks that remains undiagnosed afer a hospital workup. Being linked to more than 200 diseases, FUO remains one of the most difcult diagnostic challenges in medicine. Interestingly, FUO can be an unusual frst clinical manifestation of pheochromocytoma [2]. In this report we describe a 45-year-old woman with pheochromo- cytoma who presented with FUO, normal blood pressure levels, normal levels of urine and plasma metanephrines, and laboratory fndings suggestive of a marked infammatory status. 2. Case A 45-year-old woman was admitted to our Internal Medicine ward with FUO. She had been well until two months before presentation, when she had a lef foot injury and few days later she began to have daily fever (continuous, without chills, and with fuctuations in body temperature between 38 ∘ C and 39 ∘ C). She saw her primary care physician who ordered an X-ray of lef foot that did not show fractures. Because of persisting fever without associated symptoms, full blood count, infammatory markers, urinary cultures, and chest X-ray were ordered. Laboratory tests revealed anemia (hemoglobin 10.2 g/dL, hematocrit 32.2%, and mean corpuscular volume 81 f), a normal white cell and platelet count, and both an elevated erythrocyte sedimentation rate (ESR) (135 mm/h) and an elevated C-reactive protein (CRP) level (12 mg/dL, normal 0-1). Urinary cultures were negative and chest X-rays showed no infltrates. Despite the absence of respiratory symptoms, she was treated empirically with a 10-day course of oral clarithromycin and i.m. cefriaxone, without resolution of fever. Afer completion of antimicrobial therapy, she returned to her primary care physician who ordered further tests. Serologic tests for hepatitis B and hepatitis C viruses, cytomegalovirus (CMV), Epstein-Barr virus (EBV), and antistreptolysin O were negative. Tests Hindawi Publishing Corporation Case Reports in Medicine Volume 2016, Article ID 3489046, 5 pages http://dx.doi.org/10.1155/2016/3489046