Rosai-Dorfman disease involving breast tissue in a pediatric male patient: A case report

Introduction: Rosai-Dorfman Disease (RDD), an entity first described in 1969 is a rare disorder characterized by proliferation of histiocytes that primarily occurs in lymph nodes. In the breast, RDD is extremely rare. Although the disease typically has a slow progressive nature, it is important to recognize it as it can mimic malignancy.Case presentation: We present a case of a 17-year-old male with no significant past medical history who presented to the pediatric surgery office for evaluation of a left-sided breast mass that was suspicious for malignancy. The ultrasound findings were non-diagnostic at the time. Although further workup of this mass may have been achieved by CT scan, MRI or core biopsy, the decision was made to proceed with upfront surgical resection for both diagnostic and therapeutic purposes. Final immunohistochemistry of the mass revealed atypical large histiocytes positive for CD68 with co-expression of S100 consistent with RDD. At the time of publication, the patient is alive and well. He has not received any further therapy for RDD and there were no signs of recurrence.Conclusion: The diagnosis of Rosai-Dorfman disease can be quite challenging. Given the variable presentation and nonspecific imaging findings, definitive diagnosis relies on histopathologic findings. Pediatric patients with unifocal RDD involving the breast can be effectively treated with surgical resection safely as both a diagnostic and therapeutic option.