Kuppe et al. Allergy, Asthma & Clinical Immunology 2012, 8:6 http://www.aacijournal.com/content/8/1/6 Case report The patient, a 27 year-old male, presented initially to his general practitioner because of increasing back pain. As an electrical mechanic he traveled extensively from Ger- many to China, Russia and South Korea and was mainly involved in the installation of electronic devices in newly built tunnels. Due to back pain and an evolving neuro- logical deficit of the lower extremities, the patient was admitted to an external orthopaedic department. A mag- netic resonance imaging (MRI) of the spine revealed an atypical tumour in the left upper lung lobe encasing the vertebrae Th3-Th4. A computerized tomography (CT) of the thorax revealed a mass of 3.9 cm x 2.9 cm in the left upper lung lobe (Figure 1A, B, arrows). Histological examination of a biopsy of the mass showed an IPT with large amounts of histiocytes, lymphocytes and plasma cells (Figure 1C, D). After neurosurgical therapy, the neurological deficit in the lower extremities improved and the patient was discharged. In a second operation, the lung tumour was removed. Histological examination of this material also revealed an IPT. Given the extensive travel history of the patient, various infectious agents were excluded (mycobacteria, legionella, Borrelia burg- dorferi, pneumocystis, Epstein-Barr virus (EBV), herpes simplex virus, human immunodeficiency virus-1/2, parvovirus, respiratory viruses, cytomegalovirus (CMV) and other bacteria, stool pathogens and urinary histo- plasma antigen). During the following two years, the pa- tient was intermittently treated with corticosteroids, and low-dose radiation therapy was performed in order to Page 2 of 6 control tumour growth locally, as recommended previ- ously [10]. After two-and-a-half years, the internal fixator was removed without complications. A few days later, the pa- tient presented to a general practitioner because of dizzi- ness and mild fever. The operation wound appeared normal and laboratory tests revealed no evidence of infec- tion. During the following two weeks, the symptoms increased and the patient was admitted to the hospital. Postoperative spondylodiscitis was ruled out by CT and MRI of the spine. The CT scan revealed enlarged medias- tinal lymph nodes and hepatomegaly. Subsequently, he developed SIRS and was admitted to the intensive care unit. Blood cultures, initial bone marrow aspiration as well as a biopsy and transesophageal echocardiography all came back negative or normal. Histologic examination of material obtained during mediastinoscopy as well as a bronchial lavage showed no malignant cells; the CD4/CD8 ratio was not elevated. No granulomas were observed and sarcoidosis thus appeared unlikely. Subsequently, both elbows started to appear swollen and hot. A biopsy ruled out fasciitis but immunohistopathological evaluation showed histiocytic inflammation with CD68-positive foamy histiocytes and absence of CD1a immunoreactivity (excluding a Langerhans cell histiocytosis) (Figure 2 A-C). A liver biopsy was performed; the tissue showed no signs of sarcoidosis and only a mild non-specific inflammatory response. Additionally, there was no evidence for a malig- nant B- or T-cell lymphoma in subclonal tests using semi- nested PCRs of the biopsy material from the lungs. A Figure 1 Aspects of the pseudoinflammatory tumour of the lung in the patient. (A) A chest radiography revealed a mass in projection of the upper left lung lobe. (B) A computed tomography of the lung revealed a mass in the left lobe of the lung in contact with the thoracic spine. (C-D) Histological analysis revealed the diagnosis of a pseudoinflammatory tumour, with the characteristic spindle-like cell structure of fibroblasts.