Autopsy Findings in A Case of Pulmonary Langerhans Cell Histiocytosis-Associated Pulmonary Hypertension

Objective: Rare disease Background: Pulmonary Langerhans cell histiocytosis (PLCH) can be associated with pulmonary hypertension, although this association is more prevalent with other interstitial lung diseases. However, the diagnosis and effective treatment strategies for PLCH-associated pulmonary hypertension remain controversial. Case Report: A 27-year-old woman, who was an ex-smoker, was diagnosed with multiple diffuse pulmonary cysts. At 35 yearsof-age, she developed neurogenic pituitary diabetes insipidus and was diagnosed with PLCH-associated pulmonary hypertension. Despite treatment, including sildenafil, bosentan, and prostanoids, she died at 39 years-ofage. At the autopsy examination, the heart showed right ventricular dilation and hypertrophy. Histopathological examination of the lungs showed severe hypertrophy of the media of the small pulmonary arteries. The diagnosis of PLCH was confirmed by S100-positive immunohistochemical staining. Conclusions: The autopsy findings of a case of PLCH with severe pulmonary hypertension are reported. The mechanism of pulmonary hypertension in this disease may involve a combination of World Health Organization (WHO) Group 1 pulmonary arterial hypertension (PAH) and Group 3 pulmonary hypertension secondary to lung disease, even though PLCH is currently classified as Group 5. The use of pulmonary artery vasodilators, such as sildenafil, may be effective for the treatment of PLCH-associated pulmonary hypertension, but treatment should be considered individually for each patient. Controlled clinical trials of pulmonary artery vasodilator therapy for this condition are needed.