Interstitial lung disease was suspected, but biopsy revealed pulmonary lymphangitis carcinomatosa.

Introduction: Pulmonary lymphangitis carcinomatosa is a rare and severe manifestation of metastatic disease that causes pulmonary symptoms and radiologic patterns similar to interstitial lung diseases.

Case presentation: We report a case of a 78-year-old woman who presented to our department with insidiously developed symptoms of fatigue, dry cough, and severe dyspnea for 3 months. Chest radiography showed bilateral interstitial changes. On suspicion of interstitial lung disease, bronchoscopy and transbronchial cryobiopsy were carried out. Surprisingly, histopathological investigation revealed pulmonary lymphangitis carcinomatosa originating from primary breast adenocarcinoma.

Conclusion: To achieve an accurate diagnosis and prevent delay of initiation of proper treatment a thorough diagnostic approach is necessary. In case of doubt, biopsy should be performed to secure clarification. In this case report we discuss the diagnostic value of transbroncial cryobiopsy for this purpose.