62 • Clinical Lymphoma June 2004 Introduction Accurate detection of disease sites and assessment of response to therapy are critical for management of Hodgkin’s lymphoma (HL) and non-Hodgkin’s lymphoma (NHL), determining prognosis and therapeutic approach. Positron emission tomography (PET) using [ 18 F]fluorodeoxyglucose (FDG) has become an important tool for the evaluation of lymphomas at diagnosis and following therapy. Since the 1920s, it has been observed that most tumor cells depend on glycolysis for a disproportionate amount of their bioenergetic needs. 1 FDG- PET is a functional imaging modality based on cellular uptake and phosphorylation of FDG by tumor cells in a manner and rate similar to glucose. Because 2-deoxyglucose cannot be further metabolized, the fluorine-18 label is concentrated in cells with high metabolic activity, such as tumor cells. Positron emission tomography imaging can detect the intensity of FDG concentration in tissues, making FDG-PET an ideal imaging modality in malignancy. Several groups have studied FDG-PET imaging in HL and NHL. In general, FDG-PET appears to be highly accurate for determining sites of soft tissue involvement for most lymphomas. 2-8 For specific extranodal sites, especially bone marrow, the accuracy of FDG-PET in identifying lymphoma involvement is less clear. 5,9-12 Although most studies have found that the absence of increased FDG uptake in the bone marrow does not rule out disease involvement, the presence of PET abnormalities has been reported to be predictive of the presence of disease in this location. However, an increase in metabolic activity for any reason can lead to abnormal FDG accumulation. We report the case of a patient with HL in whom FDG-PET strongly suggested bone marrow involvement by disease, although histopathologic examination of the bone marrow showed only reactive myeloid hyperplasia without evidence of malignancy. Case Report A previously healthy 58-year-old woman presented with progressive dyspnea on exertion, nonproductive cough, low- grade fevers to 38°C, fatigue, anorexia with weight loss of 15 pounds, pruritis, and a rapid heart rate. She denied having night sweats. A chest radiograph showed left upper lobe consolidation, and she was treated with an antibiotic for presumed pneumonia without improvement. A follow-up chest radiograph showed no change in the left upper lobe abnormality, and ultimately a computed tomography (CT) scan of the chest was performed that showed a left-sided mediastinal mass extending into the left lung with left upper lobe consolidation. Bronchoscopic examination with biopsy and CT- Enhanced Marrow [ 18 F]Fluorodeoxyglucose Uptake Related to Myeloid Hyperplasia in Hodgkin’s Lymphoma Can Simulate Lymphoma Involvement in Marrow Rebecca L. Elstrom, 1 Donald E. Tsai, 1 Jo-Anne Vergilio, 3 Lisa H. Downs, 1 Abass Alavi, 2 Stephen J. Schuster 1 [ 18 F]Fluorodeoxyglucose (FDG) positron emission tomography (PET) is increasingly used for the clinical staging of lymphomas and for assessment of response to therapy. We report the case of a woman with classic Hodgkin’s lymphoma who had marked FDG uptake by tumor and bone marrow suggestive of diffuse marrow involvement by lymphoma. However, iliac crest bone marrow examination showed marked myeloid hyperplasia without evidence of lymphoma involvement. We discuss the implications for interpretation of FDG-PET imaging of bone marrow in lymphomas. Clinical Lymphoma, Vol. 5, No. 1, 62-64, 2004 Key words: Bone marrow biopsy, Clinical staging, Cytokines, Positron emission tomography Abstract Case Report Address for correspondence: Stephen J. Schuster, MD, Division of Hematology- Oncology, 16 Penn Tower, 3400 Spruce St, Philadelphia, PA 19104 Fax: 215-662-4064; e-mail: stephen.schuster@uphs.upenn.edu Submitted: Mar 6, 2003; Revised: Apr 16, 2003; Accepted: Apr 30, 2003 1 Department of Medicine 2 Department of Nuclear Medicine 3 Department of Pathology and Laboratory Medicine University of Pennsylvania Medical Center, Philadelphia Electronic forwarding or copying is a violation of US and International Copyright Laws. Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by Cancer Information Group, ISSN #1526-9655, provided the appropriate fee is paid directly to Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923 USA 978-750-8400.