What are the other main differential diagnoses for thickened interlobular septae?
Sarcoidosis; pulmonary oedema; and less common: viral pneumonia, radiation pneumonitis and lymphocytic interstitial pneumonitis (LIP).
True or false: Lymphangitic carcinomatosis results from hematogenous spread to the lung, with subsequent invasion of interstitium and lymphatics?
Nodular and irregular thickening of peribronchvascular interstitium and interlobular septa are seen in both lungs. Multiple metastatic nodules also are noted.