Pulmonary lymphangioleiomyomatosis: high-resolution CT findings

Lymphangioleiomyomatosis (LAM) of the lung is a very rare disease. There are obvious discrepancies in the literature concerning the appearance of LAM on CT scans of the lung. This study adds the imaging findings of 11 patients and demonstrates how the imaging findings changed over time in four patients. Twenty-two CT examinations, and radiographs that had been obtained close to the CT examinations, of 11 patients with LAM confirmed by open lung biopsy were retrospectively evaluated with particular attention to the size of cystic lesions and wall thickness. Furthermore the CT scans were analysed for the type of pulmonary infiltration process and its distribution, presence or absence of pleural effusion, pneumothorax and lymph node enlargement. Clinical and CT follow-up studies were available in four patients. The CT scans revealed an increase in the interstitial pattern in all patients. Architectural distortion was seen in two patients and cystic lesions were present in all. The size of the cysts varied from small lesions to bullous emphysema. The cystic lesions revealed a wall thickness up to 2 mm but a wall was not perceptible in all. Pneumothorax was seen in only two patients; pleural effusion was seen in two patients. CT examination of patients with LAM reveals neither a uniform nor a pathognomonic appearance. In the early stages of LAM or in cases with interstitial changes the differential diagnosis of centrilobular emphysema or idiopathic pulmonary fibrosis seems to be more difficult than most authors believe.