A rarity in breast pathology: First recurrent male case of Rosai-Dorfman disease

INTRODUCTION: Rosai-Dorfman Disease (RDD) is a rare pathological finding in the breast. Although it is usually palpated as a breast mass, it can be identified on ultrasound or mammogram. The hallmark of the disease is histiocytes with emperipolesis. The case presented in this study represents the first known documented male breast recurrence of RDD and the first association of the disease with pseudoangiomatous stromal hyperplasia (PASH). PRESENTATION OF CASE: A 55-year-old male, with a prior history of right breast excisional biopsy of a mass in 2015 that showed RDD, presented to our breast clinic for follow up. A breast sonogram showed a hypoechoic mass. Biopsy and excision were performed revealing recurrent RDD along with PASH. DISCUSSION: RDD is a benign condition that normally presents in lymph nodes but can present in extranodal sites, such as the breast. Location and symptoms guide treatment which can include medical or surgical therapy. PASH of the breast is a benign process that may be amenable to treatment by observation, medical management, or surgical excision. Treatment continues to be controversial given the lack of long term sequelae. CONCLUSION: Definitive treatment for RDD of the breast and PASH has not been established. Based on the available data in the literature, our conclusion is that recurrent RDD of the breast can be observed without need for surgical therapy.