CT Department of General Hospital "Sotiria". Athens.

                        Director assistant: Iris Tsaggaridou

  Mail, 69 years old. Known pulmonary hypertension and respiratory failure type II.

Answer:

Histiocytosis X constitutes 4% of all diffuse lung diseases . The etiology of the disease is unknown, although it is related to smoking, since over 90% of patients are active smokers. It mainly offends men (ratio of men to woman: 5 to 1) of young and middle age. In 60% of all cases pulmonary localization is only observed, in 20% osseous localization and in 20% visceral localization is also seen.

Histology: during the initial stages of the disease, granulous formation is observed in a rather normal pulmonary parenchyma. Many of the alterations are located centrilobulary round the small ventilators.The initial alterations are interstitial nodules which are formed by cellular populations that are constituted by formal Langerhans' cells and eosinophilic cells, neutrophilic cells, plasmacytes, lymphocytes and macrophages. Infrequently the invasion and obstruction of vessels from Langerhans' cells leads to necrosis, while cavitation of the nodules is frequent. By the healing in the centre of the alteration, fibrillous reticulum is formed. The obstruction of the bronchioli causes progressive fibrosis of the vesical walls and finally cystic formation.

Symptoms vary. 20% of the patients are asymptomatic and the disease is discovered accidentally on chest radiographs. In 20% it is presented as spontaneous pneumothorax while in most of the patients as a progressively worsened cough and dyspnea.

On simple C.T and on high resolution chest computed tomographies, nodular and cystic alterations are observed. The nodular alterations are of 1-5 mm in diameter and of smooth roundings. Bigger nodules (> 10 mms) exist but they are infrequent. Their number varies depending on the gravity of the disease. Usually they are seen as dense lesions but they might present a hypodense centre. Cysts are the main finding and usually are smaller than 10 mms. The cystic wall could be very thin or, of thickness of a few thousand mms. They may be round or may have curious forms and they may as well be seen as gatherings that create cysts of larger diameter(over 20 mms). Cysts or nodules are localized mainly in the upper lobes, bilaterally (57%), while lower lobes and costophrenic ankles remain intact. Usually regions of ground glass appearance are also seen, the density of the lungs is increased, while the volume of the lungs is normal. In most patients the course of the disease is benign which often recedes without treatment. In a small percentage the pulmonary parenchyma is progressively occupied by nodular cysts with exception of the basic departments of the lungs.

The differential diagnosis should include emphysema, cavitated nodules and bronchectasis.

Bibliography:

1. Naidich-Computed tomography and magnetic resonance of the thorax.

2. Mathias Prokop & Michael Galanski – Spiral and multislice computed tomography of the body.

3. Sutton &Young- Clinical Radiology.

4. Vlachos Lampros - Modern diagnostic  Imaging.(Βλάχος Λάμπρος-Σύγχρονη διαγνωστική απεικόνιση).

5. Wegener H. Otto-Whole body computed tomography.

6. Ivan Damjanov & James Linder-Anderson’s pathol.

                                                                                                                                                                                    G. Vakrinos.