SESSION TYPE: ILD Cases II
PRESENTED ON: Tuesday, October 23, 2012 at 11:15 AM - 12:30 PM
INTRODUCTION: Interstitial lung diseases are a heterogeneous group of disorders that are poorly understood at a molecular level. Mutations in the surfactant protein-C (SFTPC) gene are associated with chronic interstitial lung diseases in both pediatric and adult patients by accumulation of mutated proSP-C protein in the Type-II cell. We present an interesting case of a now 19 years old girl with endogenous lipoid interstitial pneumonia potentially due to the intron polymorphism in SP-C gene (IVS1-7G>A).
CASE PRESENTATION: 15 year old girl with no significant past medical history presented with symptoms of progressively worsening exertional dyspnea of 6 months duration. Extensive multisystem review was otherwise negative. No family members had significant lung disease. Her lungs were clear on examination. Laryngoscopic evaluation revealed normal vocal cord function. Her chest x-ray revealed slight interstitial prominence and a CT scan showed innumerable subpleural blebs as well multiple parenchymal blebs at the lung bases. An extensive laboratory evaluation including CBC, CRP, ESR, alpha-1-antitrypsin levels, karyotyping and TS genetic mutations were unremarkable. She underwent VATS with wedge biopsy, which revealed subpleural and intraparenchymal epithelium-lined small cysts with focal intramural smooth muscle and findings suggestive of endogenous lipoid pneumonia. Immunohistochemical staining was very robust for proSP-C. Genetic testing for SP-B and ABCA-3 deficiency was negative, however, a known mutation (IVS1-7G-A) of SP-C deficiency was identified, which was heterozygous. She had numerous pulmonary function tests over time, that continued to show a mildly restrictive pattern but seemed to be declining over time. The flows did not change following exercise or albuterol. Her FEV1 was 80% predicted at presentation, which decreased to 57% predicted 3 years later along with 10% decline in her DLCO in the same period. Her DL/VA reduced from 78% to 65% predicted. Repeat chest x-ray and CT-scan showed increase in interstitial markings as compared to previous films.
DISCUSSION: So far, there has been only one case of usual interstitial pneumonitis reported with IVSI-7G>A mutation. Lung biopsy and Genetic testing are gold standard for diagnosis. PFT’s are a sensitive tool to monitor the progression of disease as radiological findings may lag compared to clinical progression. Progressive pulmonary fibrosis is the usual outcome. Steroids and/or Plaquenil are the usual treatment of choice.
CONCLUSIONS: This is a rare case of heterozygous mutation in the SFTPC gene (IVSI-7G>A) presenting as lipoid interstitial pneumonia.
1) Fan LL Chronic interstitial lung disease in children. Pediatr Pulmonology 1993;16:184-196.
DISCLOSURE: The following authors have nothing to disclose: Rizwana Popatia, Dawn Ericson
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