{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,11]],"date-time":"2026-11-11T23:37:08Z","timestamp":1794440228138,"version":"4.9.1"},"reference-count":27,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,6,12]],"date-time":"2026-06-12T00:00:00Z","timestamp":1781222400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Oncol."],"abstract":"<jats:p>Bilateral synchronous breast cancer accounts for a small proportion of all breast cancer cases, and those with markedly different pathological and molecular subtypes are extremely rare. Such cases pose substantial challenges in accurate diagnosis, treatment decision-making, and prognostic evaluation. Here, we present a 51-year-old postmenopausal female patient who presented with an incidental painless left breast mass. Imaging examinations revealed multiple bilateral breast lesions classified as BI-RADS 4A, 4B, and 4C. All clinical and imaging data were reviewed by the multidisciplinary tumor board to develop personalized treatment regimens. Intraoperative frozen pathology verified bilateral breast malignancy, and the patient received bilateral mastectomy. Postoperative pathological examination confirmed two independent primary breast cancers: the right breast lesion was invasive breast carcinoma with apocrine differentiation showing a triple-negative immunophenotype, while the left breast contained multifocal mucinous carcinoma with a luminal-like immunophenotype. Subsequent adjuvant therapy included six cycles of TAC chemotherapy (liposomal doxorubicin, liposomal paclitaxel, and cyclophosphamide), followed by eight cycles of capecitabine maintenance therapy and long-term adjuvant endocrine therapy with exemestane. At 31 months postoperatively, the patient remained disease-free with no signs of local recurrence or distant metastasis. This case highlights the importance of comprehensive imaging evaluation, thorough pathological examination, accurate molecular subtyping, and individualized multidisciplinary treatment for patients with synchronous bilateral breast cancer of heterogeneous subtypes.<\/jats:p>","DOI":"10.3389\/fonc.2026.1861415","type":"journal-article","created":{"date-parts":[[2026,6,12]],"date-time":"2026-06-12T09:28:14Z","timestamp":1781256494000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":1,"title":["A case report of synchronous bilateral breast cancer with distinct histological subtypes and favorable long-term survival"],"prefix":"10.3389","volume":"16","author":[{"given":"PingBo","family":"Zhang","sequence":"first","affiliation":[{"name":"Department of Breast Surgery, Jilin Cancer Hospital","place":["Changchun, Jilin, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"DaWei","family":"Zhao","sequence":"additional","affiliation":[{"name":"Department of Breast Surgery, Jilin Cancer Hospital","place":["Changchun, Jilin, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,6,12]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"49","DOI":"10.1038\/s41392-024-02108-4","article-title":"Breast cancer: pathogenesis and treatments","volume":"10","author":"Xiong","year":"2025","journal-title":"Signal Transduction Targeted Ther"},{"key":"B2","doi-asserted-by":"publisher","first-page":"1940","DOI":"10.3390\/diagnostics12081940","article-title":"Synchronous\/metachronous multiple primary Malignancies: review of associated risk factors","volume":"12","author":"Pan","year":"2022","journal-title":"Diagnostics (Basel Switzerland)"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1136\/esmoopen-2017-000172","article-title":"Multiple primary tumours: challenges and approaches, a review","volume":"2","author":"Vogt","year":"2017","journal-title":"ESMO Open"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.1001\/jamadermatol.2019.1134","article-title":"Comparison of survival between patients with single vs multiple primary cutaneous melanomas","volume":"155","author":"El Sharouni","year":"2019","journal-title":"JAMA Dermatol"},{"key":"B5","doi-asserted-by":"publisher","DOI":"10.14740\/jmc4167","article-title":"Synchronous occurrence of triple-negative breast cancer and Malignant melanoma","volume":"14","author":"Taushanova","year":"2023","journal-title":"J Med cases"},{"key":"B6","doi-asserted-by":"publisher","first-page":"1045","DOI":"10.1186\/s12885-021-08766-9","article-title":"Risks and cancer associations of metachronous and synchronous multiple primary cancers: a 25-year retrospective study","volume":"21","author":"Tanjak","year":"2021","journal-title":"BMC Cancer"},{"key":"B7","doi-asserted-by":"publisher","DOI":"10.7150\/jca.25482","article-title":"Multiple primary Malignant tumors - a clinical analysis of 15,321 patients with Malignancies at a single center in China","volume":"9","author":"Zhai","year":"2018","journal-title":"J Cancer"},{"key":"B8","doi-asserted-by":"publisher","DOI":"10.3390\/life14081008","article-title":"Synchronous breast and colorectal Malignant tumors-a systematic review","volume":"14","author":"Iorga","year":"2024","journal-title":"Life (Basel Switzerland)"},{"key":"B9","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/j.humpath.2019.07.008","article-title":"Synchronous and metachronous bilateral breast cancer: clinicopathologic characteristics and prognostic outcomes","volume":"92","author":"Mruthyunjayappa","year":"2019","journal-title":"Hum Pathol"},{"key":"B10","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1023\/a:1010661514306","article-title":"Contralateral breast cancer: molecular differentiation between metastasis and second primary cancer","volume":"67","author":"Janschek","year":"2001","journal-title":"Breast Cancer Res Treat"},{"key":"B11","doi-asserted-by":"publisher","DOI":"10.14740\/wjon1603","article-title":"Synchronous bilateral breast cancer with discordant receptor status: treating one patient but two diseases","volume":"14","author":"Ojo","year":"2023","journal-title":"World J Oncol"},{"key":"B12","doi-asserted-by":"publisher","DOI":"10.1007\/s00428-021-03185-4","article-title":"Apocrine lesions of the breast","volume":"480","author":"Quinn","year":"2022","journal-title":"Virchows Archiv: Int J Pathol"},{"key":"B13","doi-asserted-by":"publisher","first-page":"7","DOI":"10.1136\/jclinpath-2018-205485","article-title":"Apocrine lesions of the breast: part 2 of a two-part review. 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