Occult pulmonary lymphangitic carcinomatosis presenting as 'chronic cough' with a normal HRCT chest

• Asthma, GERD and postnasal drip are the 3 most common causes of chronic cough.
• Constitutional symptoms (weight loss etc.) never occur in chronic cough.
• Pulmonary lymphangitic carcinomatosis can rarely present with chronic cough.

A diagnosis of ‘chronic cough’ (CC) requires the exclusion of sinister pulmonary pathology, including infection and malignancy. We present a patient with a 3 month history of CC who had an extensive workup including a normal high resolution computed tomography of the chest (HRCT) 6 weeks prior to consultation at our center. He subsequently developed constitutional symptoms including weight loss and loss of appetite 5 weeks after initial consultation. A repeat HRCT chest and a subsequent whole body PET scan found that he had developed extensive pulmonary lymphangitic carcinomatosis (PLC) from a colon primary. Treatment of the colon cancer resulted in significant decrease in metastatic disease burden and cough resolution. PLC is a very rare cause of ‘chronic cough’ and incipient/occult PLC presenting with chronic cough and a normal initial HRCT chest has not been previously reported.