Primary breast lymphoma: a case series and review of the literature

Primary breast lymphoma (PBL) is a very rare form of non-Hodgkin's lymphoma (NHL), defined as a malignant primary lymphoma occurring in the breast in the absence of previously detected lymphoma localizations. Our study aims to retrospectively evaluate the epidemiological, clinical, and imaging findings and therapeutic features of breast lymphomas in patients with primary lymphoma of the breast.

This is a retrospective study including 13 patients with primary non-Hodgkin's lymphoma of the breast treated at the Salah Azaiez Institute of Oncology from 2000 to 2019. This sample includes 1 case of follicular lymphoma, 2 cases of large T-cell lymphoma, and 10 cases of large B-cell lymphoma.

Patients included in the study were aged between 17 and 89 years (average age of 52.6 years). All patients were referred because of a lump in the breast, and only one patient consulted with inflammatory signs in the breast. The average clinical size of the tumor was 7.2 cm, with a maximum of 15 cm. Mammography showed an oval mass with circumscribed margins in the majority of cases. Ultrasound showed in most cases a hypoechoic irregular mass or multilobulated mass with irregular margins and hypervascular on color Doppler. Magnetic resonance imaging (MRI) was performed on only three patients and showed a spiculated lesion with polycyclic limits. Eight patients underwent surgery. In our study breast lymphomas involved 10 cases of large B-cell lymphoma, one case of follicular lymphoma, and two cases of large T-cell lymphoma. In this series, 11 patients had localized stages (I + II) at diagnosis, and 2 patients had disseminated stages (stage III) of primary breast lymphoma. Seven patients underwent chemotherapy treatment alone, and five had chemotherapy with radiotherapy. The median follow-up of our patients was 53 months, ranging from 1 to 177 months. Overall survival was 71% at 3 years and 51% at 5 years.

Primary breast lymphoma is an uncommon type of breast malignancy. The optimal treatment modality is still in question because of the rarity of this disease. However, the use of combination therapy produces the most favorable results. Surgery is not yet recommended.