Pulmonary Langerhans cell histiocytosis in the end stage

A 61-year-old female patient with chronic dyspnoea without fever, malaise or weight loss. Personal history: ex-smoker of 2-3 cigarettes per day up to 40 years, pulmonary hypertension, diabetes mellitus, and bone injury which was treated with radiotherapy 20 years ago.

First, a chest X-ray was performed which revealed bilateral interstitial alteration without loss of volume and increased caliber of pulmonary arteries (Figure 1).
Later, it was completed with a chest high resolution computed tomography (HRCT). It showed a diffuse and symmetric parenchymal involvement with cysts in lower lung lobes and fibrosis in upper lung lobes (Figure 2, 3 and 4).
Finally, a video-assisted thoracoscopy was performed to obtain the definitive diagnosis. The histology shows a granuloma constituted by Langerhans cells, and inmunohistochemical staining for CD1a was positive (Figure 5).

Pulmonary Langerhans cell histiocytosis (PLCH) refers to a group of diseases of unknown aetiology, in which an accumulation of Langerhans cells occurs in different organs of the body. [1, 2]. Bone injury is the most common radiographic manifestation (occurs in 80% of patients), and has a predilection for flat bones (skull). Lung involvement is observed in 10% of patients. About 90% are smokers. PLCH affects young people (average age of 32 years) without differences in sex and race [2, 3, 4]. The most frequent symptoms (50%) are dry cough, dyspnoea or chest pain accompanied or not by constitutional syndrome. Also, they may be asymptomatic or characteristically debut with spontaneous pneumothorax (15- 20%) [1, 2, 3].

In the chest X-ray it is usually presented as a reticular pattern (corresponding to the wall of the cysts) or reticulonodular and the lung volume is usually preserved or increased [4, 5].
HRCT usually shows cysts less than one centimetre, with thin (<2mm) or thick (>2mm) walls and rounded or irregular shape. In some patients, small (most frequently) or large nodules may be seen, these may cavitate and form cysts. Therefore the pulmonary nodules are more numerous at the beginning, but after a while the number of cysts increases and exceeds the number of nodules. A feature to differentiate it from the rest of diffuse cystic lung diseases on HRCT are early centrilobular nodules, sparing of costophrenic angle.
The lesions are distributed mainly in the middle and upper lobes [4, 5, 6]. In highly evolved phases we can find fibrotic changes and signs of pulmonary hypertension [6].
The HRCT has a high diagnostic yield and a good relationship with the histology, but the definitive diagnosis is anatomopathological (as in this case) [2, 3]. The biopsy methods can be transbronchial (lower performance), guided by thoracoscopy and open.

The first therapeutic measure is to quit tobacco. In severe and symptomatic patients, the treatment consists of corticosteroids with or without immunosuppressants. In advanced stages of the disease, treatment is bilateral lung transplantation (as in this case) [4.]
50% of patients will experience clinical and radiological stabilisation and the 25% will resolve spontaneously. Others (25%) progress to respiratory failure with or without pulmonary hypertension (the main causes of death) [3, 4, 5].

Written informed patient consent for publication has been obtained.