Hyperplasia of Lymphoid Follicles and Lymphangiectasia in the Parietal Pleura in Bucillamine-induced Yellow Nail Syndrome.

Yellow nail syndrome (YNS) pleurisy is often difficult to control, and pathological examinations have rarely been reported. We herein report a case of bucillamine-induced YNS in which histopathology of the parietal pleura revealed hyperplasia of the lymphoid follicles and lymphangiectasia. Even after the discontinuation of bucillamine, the pleurisy and lymphedema showed no change. Based on the histopathological findings showing similarity to rheumatoid pleurisy, we administered corticosteroid treatments, and both the pleurisy and lymphedema improved. The findings in the present case suggest that, in bucillamine-induced YNS, pleurisy may be related to inflammation caused by rheumatoid arthritis in addition to abnormalities in lymphatic vessels.