The authors describe a case of a female patient, who presented with a rapidly expanding mass of the right breast as the first clinical sign of a Burkitt-like lymphoproliferative disorder. Massive bone marrow infiltration with leukemic spillover and limited lymph node involvement were subsequently detected. The difficulties encountered in classifying, according to current schemes, the observed lymphoid neoplasm are emphasized. Moreover, an evaluation of the true rarity of mammary localizations at the onset of lymphoid malignancies, based on a review of the literature, suggests, especially for the most malignant varieties, a higher frequency than supposed.