Background:   The most common site of postoperative breast cancer recurrence is bone, followed by local relapse, lung, and liver. The majority of relapses occur within the first 3 years after surgery. Pleural recurrences more than 10 years after surgery are rare.
Case Report:  A 94-year-old woman who had undergone modified radical mastectomy for right breast cancer (invasive ductal carcinoma, pT2, pN1, ER+, PgR+) 12 years earlier presented to our hospital with carcinomatous pleuritis and a chief complaint of dyspnea. Endocrine therapy with oral letrozole was started and the pleural effusion had disappeared 3 months later.
Conclusions: Oral endocrine therapy may be effective for the treatment of late recurrence of hormon receptor-positive breast cancer in elderly women.

Keywords: endocrine therapy, breast cancer, late recurrence, Malignant pleural effusion