Primary breast lymphoma mimicking triple-negative breast cancer: a case report with clinical and pathological implications

Toyoaki Sawano; Masahiro Wada; Akihiko Ozaki; Akinori Hashiguchi; Shinichi Hirooka; Tetsuya Tanimoto

doi:10.1186/s40792-024-02032-3

Primary breast lymphoma mimicking triple-negative breast cancer: a case report with clinical and pathological implications

Surg Case Rep. 2024 Oct 8;10(1):234. doi: 10.1186/s40792-024-02032-3.

Authors

Toyoaki Sawano^{1

2}, Masahiro Wada^{3

4}, Akihiko Ozaki³, Akinori Hashiguchi⁵, Shinichi Hirooka⁶, Tetsuya Tanimoto⁷

Affiliations

¹ Department of Surgery, Jyoban Hospital of Tokiwa Foundation, 57 Kaminodai, Jyoban-Kami-Yunagayamachi, Iwaki, Fukushima, Japan. toyoakisawano@gmail.com.
² Breast and Thyroid Center, Jyoban Hospital of Tokiwa Foundation, Iwaki, Fukushima, Japan. toyoakisawano@gmail.com.
³ Breast and Thyroid Center, Jyoban Hospital of Tokiwa Foundation, Iwaki, Fukushima, Japan.
⁴ Department of Breast Surgery, Utsunomiya Central Clinic, Utsunomiya, Tochigi, Japan.
⁵ Department of Pathology, Keio University School of Medicine, Shinjuku, Tokyo, Japan.
⁶ Department of Pathology, Jyoban Hospital of Tokiwa Foundation, Iwaki, Fukushima, Japan.
⁷ Department of Internal Medicine, Jyoban Hospital of Tokiwa Foundation, Iwaki, Fukushima, Japan.

Abstract

Background: Primary breast lymphoma (PBL) is a rare type of extranodal lymphoma, the diagnostic process for which presents significant challenges owing to an overlap in clinical and pathological features with those observed in triple-negative breast cancer (TNBC). However, the current literature reveals a paucity of information regarding the ramifications of potential diagnostic errors, particularly in the context of emergent therapeutic strategies for TNBC. Thus, we present a unique report of a case of PBL.

Case presentation: A 76-year-old female with no past medical or family history presented to the hospital with the chief complaint of a mass in the right breast. Two masses were palpated in the right breast: one 56 mm mass (No. 1) located at 10 o'clock, and a 21 mm large, elastic, hard mass (No. 2) at 4 o'clock. Needle biopsy was performed only on the larger 56 mm mass (No. 1). The results showed invasive carcinoma that was negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2. The preoperative diagnosis was right breast cancer (T3N0M0 Stage IIB) of the TNBC subtype. The patient refused the preoperative chemotherapy recommended by the treatment team; therefore, right breast mastectomy and sentinel lymph-node biopsy were performed instead. The histopathological diagnosis of the first mass was diffuse large B-cell lymphoma (DLBCL); that of the second mass (No. 2) was an invasive breast carcinoma of no special type. Postoperative treatment consisted of endocrine therapy (letrozole) for breast cancer, while the DLBCL was treated with chemotherapy and three courses of intrathecal chemotherapy. At the time of this report, the patient is still living, and neither tumor had recurred in the 2 years following surgery.

Conclusions: On rare occasions, PBL can preoperatively mimic TNBC. While this case did not lead to serious consequences, because surgery was eventually selected as the first therapy, clinicians should be aware that the diagnosis of PBL is challenging using only a core-needle biopsy and can often be misdiagnosed as TNBC.

Keywords: Carcinoma; Diffuse large B-cell lymphoma; Extranodal lymphoma; Lymphoma of the breast; Triple-negative breast cancer.