Primary Breast Lymphoma in Mexico: A 15-Year Retrospective Case Series From a Tertiary Center Suggesting a Distinctly Early Age at Presentation.

BACKGROUND

Primary breast lymphoma (PBL) is a rare extranodal lymphoma involving breast tissue and most commonly affects women in the sixth to seventh decades of life. We describe a clinicopathological series of PBL cases diagnosed at a tertiary referral center in Mexico. Histologically, most cases correspond to B-cell non-Hodgkin lymphomas, particularly diffuse large B-cell lymphoma (DLBCL). Due to its rarity, available evidence is largely derived from small case series and retrospective analyses, highlighting the need for additional reports from diverse populations.

METHODS

A retrospective, observational, descriptive study was conducted at a tertiary referral center in Mexico. All cases diagnosed as PBL between 2005 and 2020 were retrieved from the institutional pathology database. Inclusion criteria consisted of a histopathological diagnosis of primary lymphoma involving the breast with availability of complete histopathological material, including paraffin blocks and immunohistochemical studies. Descriptive statistics were used. Continuous variables are expressed as mean ± standard deviation, and categorical variables as absolute frequencies and percentages. Due to the small sample size, no inferential statistical analysis was performed.

RESULTS

Six cases met the diagnostic criteria for PBL (N = 6), and all patients were women. The mean age at diagnosis was 38.2 ± 19 years (range, 19-66). DLBCL was the most frequent subtype (4/6, 66.7%), followed by classical Hodgkin lymphoma (1/6, 16.7%) and B-lymphoblastic lymphoma (1/6, 16.7%). Left breast involvement was observed in three cases, right-sided disease in one, bilateral presentation in one, and one case lacked specified laterality.

CONCLUSIONS

In this single-center Mexican series, patients were diagnosed at a younger age than typically reported in the international literature. DLBCL was the predominant subtype. These findings suggest the possibility of population-specific epidemiological patterns and underscore the need for larger regional studies to clarify potential differences in disease presentation.