[Multicystic presentation of a lepidic mucinous adenocarcinoma]

The pneumonic form is very characteristic of lepidic pattern adenocarcinoma of the lung. However, the diagnosis and treatment of the disease when it presents in this way may be delayed by atypical radiological findings and severity of hypoxemia.

A 48-year-old female, non-smoker, asthmatic since the age of 20 years, was hospitalized for a diffuse infiltrative pneumonia complicated by severe respiratory failure. The history included chronic cough, gradually increasing dyspnoea on exertion lasting for 14 months and the onset of haemoptysis of low abundance associated with arthralgia in the previous month. She had no professional or domestic exposure to any risk factors. Chest CT scan revealed bilateral alveolar condensations, ground glass areas with thickened septa creating a crazy paving pattern, and numerous large cysts of various sizes and locations, often with irregular thin walls. Microbiological and immunological tests were negative. She required early invasive ventilation and then venovenous ECMO together with broad-spectrum empiric antibiotic therapy, but died after 39 days in intensive care. The autopsy revealed lesions consistent with mucinous lepedic adenocarcinoma with no EGFR mutation and KRAS mutation. There was also associated pulmonary suppuration.

Mucinous lepidic adenocarcinoma is an alternative diagnosis for pneumonic consolidation associated with multiple cysts.