What are some possible causes of bulky mediastinal lymphadenopathy(other than cancer) involving subcarinal, bilateral hilar and paratracheal nodes?

Sarcoid: could cause adenopathy in those regions, as well as other granulomatous inflammatory processes. Infectious processes such as histoplasmosis could do it. Certain chronic exposures such as berylliosis and silicosis could cause mediastinal adenopathy, but usually the history and other findings make those diagnoses more obvious. Unfortunately, lymphoma is the major consideration in most cases.