Autoimmune alopecia areata due to thymoma without myasthenia gravis: a case report oleh Yukino Saito, Tomohiro Yazawa, Toshiteru Nagashima, Yoichi Ohtaki, Natsuko Kawatani, Eiji Narusawa, Ryohei Yoshikawa, Nozomi Matsumura, Tatsuro Maehara, Ken Shirabe