SESSION TITLE: Lung Cancer Case Report Posters II
SESSION TYPE: Affiliate Case Report Poster
PRESENTED ON: Tuesday, October 27, 2015 at 01:30 PM - 02:30 PM
INTRODUCTION: Pulmonary inflammatory pseudotumor is a rare tumor, representing about 1% of all lung tumors. Whether it is a true neoplasm or an inflammatory lesion with uncontrolled cell growth remains unclear.
CASE PRESENTATION: An 18 year-old man presented with 6 months of progressive dyspnea on exertion. Chest x-ray (Figure 1A) showed left lung volume loss, and a mediastinal mass encasing the distal trachea and left mainstem bronchus was seen on computed tomography (Figure 2). On bronchoscopy, the mass completely occluded the proximal left mainstem bronchus. Biopsy showed fibrotic tissue with mixed chronic inflammatory cell infiltrate. Myofibroblasts stained positive for caldesmon, concerning for inflammatory pseudotumor. Additional diagnostic workup included cervical mediastinoscopy and video-assisted thoracoscopic surgery. Surgical specimens from the mass and lymph nodes showed fibroadipose tissue with dense lymphoid infiltrate without evidence of other etiologies. Since surgical resection was not possible due to tumor location, he was started on prednisone 60 mg daily. Over a 2-month period on prednisone, his symptoms resolved, his left lung re-expanded (Figure 1B), and FEV1 increased from 1.35 to 3.09 L (36 to 74% predicted).
DISCUSSION: Inflammatory pseudotumor may affect any organ system. It is sometimes classified as a true neoplasm due to its tendency to recur and the presence of ALK gene rearrangement in a subset of cases. However, it may also represent an immunologic phenomenon with a suggestion that it results from an IgG4-related response. One histological classification system categorizes the disease based on local invasiveness. Invasive inflammatory pseudotumor, as seen in this case, is usually diagnosed in younger patients, invades the chest wall or mediastinum, and is treated with surgical resection. Complete resection is the preferred therapy to prevent recurrence. However, approximately 8 case reports have described variable efficacy of corticosteroid therapy in patients who are inoperable or in patients who have recurrence after surgery.
CONCLUSIONS: Inflammatory pseudotumor can be responsive to corticosteroid therapy alone, which therefore may be a therapeutic consideration for patients unable to undergo surgical resection.
Reference #1: Mondello B. Surgical management of pulmonary inflammatory pseudotumors: A single center experience. J Cardiothorac Surg. 2011; 6:18.
Reference #2: Kim JH. Pulmonary inflammatory pseudotumor--a report of 28 cases. Korean J Intern Med. 2002 Dec;17(4):252-8.
DISCLOSURE: The following authors have nothing to disclose: Radhika Zopey, Greg Mason, Yvonne Carter, David Hsia
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