Manifestations pulmonaires de l’histiocytose langerhansienne

Abstract

Pulmonary Langerhans cell histiocytosis is a rare diffuse cystic interstitial pneumonia of unknown etiology that occurs selectively in young smokers of both genders. The multicenter studies conducted by the reference center have better defined the short and medium terms natural history of the disease and the clinical management of patients. A substantial proportion of patients experience a dramatic decline in their lung function soon after diagnosis. Importantly, smoking cessation is associated with a decreased risk of subsequent deterioration. Cladribine, a purine analogue, chemotherapy may dramatically improve lung function in patients with progressive pulmonary Langerhans cell histiocytosis, but this treatment should be used only in the setting of clinical research. Specific pulmonary hypertension therapies (anti-endothelin receptors, inhibitors of phosphodiesterases) may be used with caution in specialized centres for patients with severe pulmonary hypertension, and seem to be well tolerated. The recent identification of the V600E mutation of the BRAF oncogene in approximately half of the Langerhans cell histiocytosis lesions, including pulmonary granulomas, represents an important step forward in the understanding of the pathogenesis of Langerhans cell histiocytosis. Potentially it opens the way to targeted therapies.

Physiologic Determinants of Exercise Capacity in Pulmonary Langerhans Cell Histiocytosis: A Multidimensional Analysis

“…Dynamic volumes (FEV 1 , FVC) were decreased in patients with impaired aerobic capacity, while static volumes (TLC, FRC) were similar in patients with and without impaired aerobic capacity. This functional profile—commonly called “pseudorestriction”—is typically observed in bronchiolar diseases, in which decreased pulmonary compliance due to cellular infiltration of the lung decreases dynamic volumes, while air trapping increases RV leading to globally normal static volumes [21]. Decreased FEV 1 and FVC were unlikely due to airway obstruction, as PC2 did not correlate with FEV 1 /FVC.…”

Histiocytose langerhansienne pulmonaire révélée par un pneumothorax: à propos d’un cas

“…L’anomalie la plus fréquemment retrouvée en pléthysmographie est un piégeage aérique dans 45% des cas, suivi d’un trouble ventilatoire obstructif dans 30% des cas puis d’un restrictif dans 6% des cas. Une baisse de la DLCO serait notée chez 80% des patients [ 3 ]. Ceci concorde avec les résultats de la pléthysmographie de notre patient où une augmentation du volume résiduel (VR) et un rapport VR/CPT à 234% et 227% respectivement étaient observés.…”

“…Leur nature langerhansienne est confirmée par immunohistochimie grâce à leur expression de l’antigène membranaire CD1a ou de la Langerine (CD207). L’aspect du granulome varie en fonction du stade évolutif et du tissu concerné [ 3 ].…”