Spontaneous regression of a clinically-advanced histologically low-grade follicular lymphoma involving the breast: case report and review of the literature.

A 68-year-old woman was diagnosed as having grade 1 follicular lymphoma of the left breast in November 2012. Bone marrow infiltration was noted histologically and confirmed by Southern blot analysis of the IgHJH locus. The clinical stage was IVA, advanced stage. According to the Follicular Lymphoma International Prognostic Index, the patient was classified into the high risk group. The general condition was good and there were no organ symptoms, therefore, the patient was kept under observation without treatment. After one year and 2 months of follow up, The mass was regressed spontaneously. As previous studies have suggested a poor prognosis of patients with an advanced clinical stage of the disease, careful follow-up of our patient is necessary.