Important Insights Regarding Primary Breast Lymphoma

Analysis of a case of primary small lymphocytic lymphoma (SLL) of the breast has brought to light several observations, including the importance of an accurate diagnosis due to its similarity with other breast malignancies and individualized treatment options curated to each patient, according to a case study presented in Oxford Medical Case Reports.¹

Breast lymphomas are classified as either primary breast lymphoma (PBL) or secondary breast lymphoma, with PBL occurring most commonly due to non-Hodgkin lymphoma (NHL) without a previous diagnosis of extramammary lymphoma.

The patient in this case had a rare presentation of NHL in the form of primary SLL. The asymptomatic, 65-year-old female patient had a medical history that included diabetes and hypertension. She was referred to her surgery clinic for further evaluation after a nondiagnostic mammogram and ultrasound (US) found a nodule in her right breast.

She had a significant family history of breast cancer, but 6 years of routine mammograms had been unremarkable. Additionally, she denied having fever, nipple discharge, breast pain, palpitations, or other key signs of breast cancer. Upon examination, there was no retraction, dimpling, or secretions of bilateral breasts. However, a US-guided core needle biopsy revealed low-grade mature small B-cell lymphoma.

Interestingly, the peripheral blood smear was normal, and complete blood count was normal outside of rare target cells, rare schistocytes, and slight poikilocytosis, the investigators wrote. Furthermore, her platelet count was normal, and no immature white blood cells were found.

After consulting with the Oncology Department, a lumpectomy was recommended, along with follow-up PET scan imaging, to which the patient agreed. The pathology report indicated atypical lymphoid cell population in the breast duct, according to the investigators.

Upon confirmation of low-grade NHL through immunohistochemical straining, in addition to the presence of positive B-cell markers for CD3, CD5, and CD20, a final diagnosis of primary SLL was made by her clinicians.

At follow-up, the PET scan showed no evidence of abnormalities, and surveillance for the patient was planned with a mammogram every 6 months for up to 2 years. The 6-month mammogram showed no significant changes or signs of malignancy, the investigation found.

Breast lymphoma is rare, with a prevalence of 0.04% to 0.7%, and current criteria for diagnosing PBL has historically aligned with the proposals of Wiseman and Liao from 1972.² After an analysis of 16 cases of PBL, the investigators proposed diagnostic criteria consisting of mammary tissue and lymphoma infiltrates that are close in proximity, no concurrent widespread disease, and no prior diagnosis of extramammary lymphoma. They also discussed the tendency of tumors in PBL to infiltrate between mammary ducts without destroying either one.

Typically, chemotherapy is the classic treatment for PBL, since radical surgical excision has been found to not influence survival or the risk of cancer recurrence, the investigators wrote. Despite this, best treatment practices for PBL have been hard to determine due to its rarity.

Findings from a case study, published by Moura et al, demonstrate the difficulty in establishing well-defined therapeutic guidelines for PBL, and emphasize that “treatment must be individualized and multimodal, with surgery reserved for patients who benefit from a better local control.”³

In the case of the patient in the present analysis, the investigators performed surgical excision for therapeutic purposes with follow-up PET scans dictating whether further treatment should be required. They noted that surgical excision may be utilized when the core needle biopsy sample is insufficient for classification or because of individualized treatment plans.

“Although there are no definite therapeutic guidelines as there are for breast carcinoma, treatment options should be individualized to each patient’s case, taking stage, symptoms, overall health, patient preference, and lymphoma subtype into consideration when deriving a treatment plan,” the investigators concluded.

References

1. Passeggiata M, Badaro G, Kim H, Umbu L, Mashburn P, Nath M. Primary small lymphocytic lymphoma of the breast: a rare presentation of non-Hodgkin’s lymphoma. Oxford Med Case Reports. 2024;2024(4):omae028. doi:10.1093/omcr/omae028
2. Wiseman W, Liao KT. Primary lymphoma of the breast. Cancer. 1972;29(6):1705-1712. doi:10.1002/1097-0142(197206)29:6<1705::AID-CNCR2820290640>3.0.CO;2-I
3. Moura C, Leite MI, Parreira R, Medeiros A. Primary breast lymphoma. J Surg Case Rep. 2020;2020(1):rjz405. doi:10.1093/jscr/rjz405