Primary MALT lymphoma of the breast: pathological and radiological characteristics

Yukiko Shibahara; Jan M A Delabie; Supriya Kulkarni; Allison Grant; Anca Prica; David R McCready; Susan J Done

doi:10.1007/s10549-024-07258-1

Primary MALT lymphoma of the breast: pathological and radiological characteristics

Breast Cancer Res Treat. 2024 Mar 1. doi: 10.1007/s10549-024-07258-1. Online ahead of print.

Authors

Yukiko Shibahara^{1

2

3}, Jan M A Delabie^{1

2

4}, Supriya Kulkarni^{5

4}, Allison Grant^{5

4}, Anca Prica^{6

4}, David R McCready^{7

4}, Susan J Done^{8

9

10}

Affiliations

¹ Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
² Laboratory Medicine Program, Department of Pathology, Toronto General Hospital, University Health Network, 200 Elizabeth Street, 11th Floor, Toronto, ON, M5G 2C4, Canada.
³ Department of Pathology, Kitasato University, Sagamihara, Kanagawa, Japan.
⁴ Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada.
⁵ Department of Medical Imaging, University of Toronto, Toronto, ON, Canada.
⁶ Department of Medical Oncology and Hematology, Princess Margaret Cancer Centre, Toronto, ON, Canada.
⁷ Department of Surgery, University of Toronto, Toronto, ON, Canada.
⁸ Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada. susan.done@uhn.ca.
⁹ Laboratory Medicine Program, Department of Pathology, Toronto General Hospital, University Health Network, 200 Elizabeth Street, 11th Floor, Toronto, ON, M5G 2C4, Canada. susan.done@uhn.ca.
¹⁰ Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada. susan.done@uhn.ca.

PMID: 38427311
DOI: 10.1007/s10549-024-07258-1

Abstract

Purpose: Primary Mucosa-associated lymphoid tissue (MALT) lymphoma is a rare diagnosis in the breast, and clinical diagnosis based on radiological features is often challenging. This study aimed to evaluate the clinicopathological, and radiological characteristics of the patients diagnosed with primary breast MALT lymphoma.

Methods: This study examined 18 cases of primary MALT lymphoma of the breast diagnosed at a single tertiary center between January 2002 to December 2020. Medical charts, radiological imaging and original pathology slides were reviewed for each case.

Results: All cases were female (gender assigned at birth) and presented with a palpable mass or an incidental imaging finding. Imaging presentation ranged from mammographic asymmetries, circumscribed masses, and ultrasound masses lacking suspicious features. Seventeen cases were biopsied under ultrasound; one received a diagnostic excision biopsy. Microscopic examination of the breast specimens demonstrated atypical small lymphocyte infiltration with plasmacytoid differentiation and rare lymphoepithelial lesions. Immunohistochemistry was performed in all cases and established the diagnosis. Most patients were treated with radiotherapy, and only three were treated with chemotherapy. The median follow-up period was 4 years and 7.5 months, and all patients were alive at the last follow-up.

Conclusion: Primary MALT breast lymphomas are usually indolent and non-systemic, and local radiotherapy may effectively alleviate local symptoms. Radiological findings show overlap with benign morphological features, which can delay the diagnosis of this unusual etiology. Although further studies involving a larger cohort could help establish the clinical and radiological characteristics of primary breast MALT lymphomas, pathology remains the primary method of diagnosis.

Trial registration number: University Health Network Ethics Committee (CAPCR/UHN REB number 19-5844), retrospectively registered.

Keywords: Breast mammogram; Breast ultrasound; Extranodal marginal zone lymphoma; MALT lymphoma; Primary breast lymphoma.