CASE REPORT Follicular localization of dendritic cells in a xanthomatous inflammatory tumor of lung associated with human herpes virus-8 infection A. B. Farris III & R. L. Kradin Received: 24 May 2006 / Accepted: 15 September 2006 / Published online: 8 November 2006 # Springer-Verlag 2006 Abstract A 17-year-old man was treated with chemother- apy and radiation for nodular sclerosing Hodgkin lympho- ma that presented as a left chest wall mass. Ten years later, a left upper lobe lung tumor was identified. The tumor resection demonstrated a 1.3-cm yellow lung nodule composed of epithelioid and spindled lipid-laden CD68+ and Factor XIIIa+ macrophages. Distinct follicular struc- tures with dendritic cells positive for CD1a, fascin, and ALK-1 and largely devoid of intracytoplasmic lipid were a distinguishing feature of the lesion. Most of the xantho- matous macrophages expressed human herpes virus-8 anti- gen. The current World Health Organization classification of “inflammatory myofibroblastic tumors” is examined, and the association of a subset of “inflammatory pseudotumors” with immunodeficiency states and opportunistic infection is discussed. Keywords Lung . Inflammatory myofibroblastic tumor . Xanthoma . Factor XIIIa . CD1a Clinical history A 17-year-old man with no significant past medical history presented with a 4-cm, indurated, nonmobile, painful mass, arising along the left parasternal border adjacent to the fourth rib. Chest computed axial tomography (CT) scanning revealed a large anterior mediastinal mass extending to the left sternoclavicular joint with extensive mediastinal adenopathy. A biopsy of the chest wall mass revealed Hodgkin lymphoma, nodular sclerosing type. No disease was present below the diaphragm, and he was treated with local irradiation and combination chemother- apy, including adriamycin, bleomycin, vinblastine, and carbazine. He remained disease-free until 10 years later when he presented with a new 1.3-cm nodule in the left upper lung lobe. He denied cough, shortness of breath, weight loss, or fever. Positron emission tomography scan demonstrated fludeoxyglucose fluorine-18 uptake in the nodule. A CT- guided percutaneous fine needle aspirate was nondiagnostic, and flexible bronchoscopy demonstrated no endobronchial lesions. A wedge resection of the left upper lobe nodule was performed. Materials and methods Sections of the tumor were frozen in a liquid nitrogen at -37°C, sectioned in a cryostat at 5 μm, and stained with hematoxylin and eosin (H&E) and Oil-Red-O. Sections of the tumor were fixed in 10% phosphate-buffered formalin, embedded in paraffin, sectioned at 5 μm, and stained with H&E and Ziehl–Neelsen stains. Immunohistochemical studies were performed on paraf- fin-embedded sections. Primary antibodies included CD1a, CD21, CD34, CD68, ALK-1, S100, Factor XIIIa, human herpes virus-8 (HHV-8), smooth muscle actin, vimentin (all from Ventana, Tucson, AZ, USA), and fascin (DAKO, Carpinteria, CA, USA). Expression of EBV-encoded RNA (EBER) was evaluated by in situ hybridization using the INFORM EBER probe (Ventana). Virchows Arch (2006) 449:726–729 DOI 10.1007/s00428-006-0318-y A. B. Farris III : R. L. Kradin Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA R. L. Kradin (*) Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA e-mail: rkradin@partners.org