INTRODUCTION:Classically, Lymphocytic Interstitial Pneumonia (LIP) occurs in association with autoimmune diseases, most often Sjogren’s syndrome; however, persons who are seropositive for human immunodeficiency virus (HIV), children in particular, are at increased risk of acquiring LIP. In adults with HIV it is an uncommon condition with incidence and prevalence rates that are largely unknown. It is a lymphoproliferative disorder characterized by a diffuse and exquisitely interstitial proliferation of small lymphocytes and plasma cells. The predominant and characteristic feature on chest computed tomography scan (CT) is that of ground glass opacification with centrilobular nodules. We describe a case of LIP in a HIV positive adult presenting with a significant amount of cystic parenchymal disease on radiographic imaging.
CASE PRESENTATION:A 46 year-old Hatian man without significant medical history complained of non-productive cough for one year, with progressive dyspnea on exertion and sixty pounds of weight loss. He denied fever, chills, hemoptysis, wheezing or pleuritic pain. He denied tobacco or illicit drug use. Examination was remarkable for digital clubbing, and bilateral basal rales. White cell count and differential were normal. Rapid HIV test was positive, and CD4 lymphocyte count was 314. Purified protein derivative skin test was negative. Chest X-ray revealed bilateral diffuse reticular nodules. CT of the chest showed multiple cysts, greater on the right, with ground glass opacification and centrilobular nodules. Mild hilar adenopathy was also present. Bronchoscopy with alveolar lavage (BAL) and trans-bronchial biopsy was performed. BAL was negative for Pneumocystis jiroveci (PCP), acid fast bacilli, fungii and viral inclusion bodies, and cultures were also negative. Trans-bronchial biopsy showed mild chronic inflammation. Pulmonary function tests showed a restrictive pattern with mild hypoxia. He refused open lung biopsy and was started on highly active anti-retroviral therapy with an increase in CD4 count to 476, without improvement in his symptoms of cough or exertional dyspnea. Radiographic abnormalities persisted. Five months after being first seen he underwent open lung biopsy with wedge resection from the right middle lobe, and a diagnosis of lymphoid interstitial pneumonitis was made. The patient was started on 60 mg daily prednisone with bactrim prophylaxis. Six minute walk test before steroids showed a walk distance of 950 feet, and improved to 1050 feet after one month of steroids. He also reported improvement in his cough and shortness of breath.
DISCUSSION:In their review of CT findings in 22 adult patients with LIP, 2 of which were HIV positive, Takeshi Johkoh et al showed that the predominant and characteristic feature was that of ground glass opacification with centrilobular nodules. 15 of these patients, one of which were HIV positive, had cystic changes, however these were of a random distribution and involved less than 10% of the lung parenchyma. Our patient though, had multiple diffuse cysts as a predominant feature, involving a very significant portion of the lung parenchyma, along with ground glass opacification, centrilobular nodules and hilar adenopathy. Multiple cysts are typically seen on chest CT in patients with pulmonary Langerhans histiocytosis and lymphangioleiomyomatosis. Distinguishing features of LIP from Langerhans histiocytosis include the presence of interlobular septal thickening and lymphadenopathy seen in the former. In patients with HIV, PCP and other AIDS-related complications, such as tuberculosis, cystic changes can also be seen. Our patient however was negative for these infections.
CONCLUSIONS:LIP must be strongly considered as part of the differential diagnosis of diffuse cystic lung disease in adult patients with HIV since some of these patients may benefit from long-term corticosteroid therapy.
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