|Topic:||19. Lung Infection (Non-Mycobacterial, i.e., Bacterial, Viral, Fungal, HIV, etc.) / Adult / Case Report / Microbiology, Tuberculosis and Pulmonary Infections (MTPI)|
|Authors:||A. Bhatt, M.M. Howsare, U. Gauhar; Louisville, KY/US|
Introduction: Xanthogranulomatous inflammation (XGI) is a pathological process that can affect many organs, with the kidneys being affected most often. Involvement of the lung may be seen in some systemic conditions like Erdheim Chester disease; however isolated lung nodules due to XGI have rarely been described.
Case: A 67 year old male with a history of chronic obstructive pulmonary disease (COPD) classification GOLD D and rheumatoid arthritis (RA) on adalimumab was admitted to the hospital for respiratory failure. Computerized tomography (CT) of the chest showed a new right lower lobe cavitary pulmonary nodule in a background of tree in bud opacities. A bronchoalveolar lavage (BAL) was performed and radial endobronchial ultrasound (EBUS) was used to perform a trans-bronchial biopsy of the lesion, which revealed foci of XGI and fibrosis. BAL and biopsy cultures grew Sternotrophomonas maltophila. The patient was treated with levofloxacin for seven days with significant improvement.
Axial CT of the chest showing a cavitary lesion and tree in bud nodules
Discussion: Immunocompromised patients with cavitary pulmonary nodules and respiratory compromise warrant bronchoscopy with BAL and biopsies to identify pathogens or malignancies. The common etiologies of cavitary lesions in immunocompromised patients are infections including mycobacterial and fungal infections, and malignancy. XGI, a destructive process can mimic these processes due to necrosis within the lesion. XGI is a pattern of inflammation involving the presence of cellular infiltrate including neutrophils, lymphocytes, plasma cells, erythrocytes, macrophages and foamy histiocytes. Escherchia coli is commonly identified as an etiological agent in XGI and Sternotrophomonas has not previously been identified in this condition. The inciting process is thought to be hemorrhage, suppuration and necrosis. It was first described, and is most commonly seen in the kidneys and genitourinary tract. Erdheim Chester disease is a systemic condition where lung involvement may be seen with similar pathological findings, however this is usually a diffuse pulmonary process in contrast to the isolated nodule our patient seen in our patient. Rheumatoid nodules can be cavitary but display a different histological pattern of palisading histiocytes around a necrotic center.
Conclusion: Immunocompromised patients are at risk for serious infections; patients on adalimumab have an increased incidence of serious infections up to 1.9-2.6 per 100 person years. Surgical pathology aids greatly in tailoring an effective treatment approach and radial EBUS offers a relatively safe approach to peripheral pulmonary lesions. XGI is an extremely unusual manifestation of inflammatory disease process in the lung.