Abstract
Lymphomatoid granulomatosis (LYG) is a rare lung disorder diagnosed by radiological imaging of multiple pulmonary nodules and occasionally induced by methotrexate (MTX) use. To date, the treatment of LYG has not been standardized. We herein report the case of a patient with grade 3 MTX-related LYG who presented a bulky lung mass. Importantly, the disease condition only improved after the discontinuation of MTX and remained stable for more than 1 year. Chest physicians should be aware that LYG can develop as a single lung mass and spontaneously regress, even without aggressive chemotherapy, following the cessation of MTX.