{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,11]],"date-time":"2026-08-11T09:38:54Z","timestamp":1786441134576,"version":"build-2736575974"},"reference-count":22,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,8,10]],"date-time":"2026-08-10T00:00:00Z","timestamp":1786320000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Curr. Oncol.","Current Oncology"],"abstract":"<jats:p>Research Background: Breast cancer is a malignant tumor that threatens women\u2019s health. Among breast cancer patients, about 4.2% to 17% may suffer from multiple primary malignant neoplasms. Cases of patients suffering from both breast cancer and multiple myeloma are relatively rare in clinical practice. This paper reports one case of a patient who developed multiple myeloma during the treatment of breast cancer. Clinical Data: The patient was a 56-year-old female, admitted to hospital due to \u201cfever for 4 days, one year after the treatment of left breast cancer\u201d. The patient was diagnosed with left breast cancer (ypT1N1M0, HER2-overexpressing subtype) approximately one year prior to presentation. Following diagnosis, the patient was treated sequentially with TcbHP and THP chemotherapy regimens, and subsequently received local radiotherapy. The patient developed fever four days prior to admission. Further laboratory examinations revealed pancytopenia, positive IgA-\u03bb-type monoclonal immunoglobulin by immunofixation electrophoresis, and myeloma cells accounting for 11% in bone marrow smears. Bone marrow immunophenotyping indicated abnormal plasma cells, and pathological results of bone marrow biopsy were consistent with multiple myeloma. The final diagnosis was breast cancer complicated with multiple myeloma. After confirmed diagnosis, the patient was transferred to another hospital for targeted treatment of multiple myeloma and has been receiving continuous treatment there up to the time of follow-up. Conclusions: For patients with breast cancer, if they develop bone pain, anemia, hypercalcemia or renal dysfunction that cannot be explained by tumor metastasis or conventional complications after surgery or during follow-up, clinicians should be alert to the possibility of second primary tumors.<\/jats:p>","DOI":"10.3390\/curroncol33080473","type":"journal-article","created":{"date-parts":[[2026,8,10]],"date-time":"2026-08-10T15:10:24Z","timestamp":1786374624000},"page":"473","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Multiple Myeloma Complicating Breast Cancer During Treatment: A Case Report"],"prefix":"10.3390","volume":"33","author":[{"given":"Lijing","family":"Guo","sequence":"first","affiliation":[{"name":"Department of General Surgery, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua Medicine, Tsinghua University, Beijing 102218, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0646-2153","authenticated-orcid":false,"given":"Zhengshuo","family":"Jin","sequence":"additional","affiliation":[{"name":"Department of Hematology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua Medicine, Tsinghua University, Beijing 102218, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuehua","family":"Huang","sequence":"additional","affiliation":[{"name":"Department of Hematology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua Medicine, Tsinghua University, Beijing 102218, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,10]]},"reference":[{"key":"ref_1","first-page":"229","article-title":"Global cancer statistics 2022: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries","volume":"74","author":"Bray","year":"2024","journal-title":"CA Cancer J. Clin."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"e187147","DOI":"10.1001\/jamanetworkopen.2018.7147","article-title":"Evaluation of the Incidence of Hematologic Malignant Neoplasms Among Breast Cancer Survivors in France","volume":"2","author":"Jabagi","year":"2019","journal-title":"JAMA Netw. Open"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Jabagi, M.J., Goncalves, A., Vey, N., Le Tri, T., Zureik, M., and Dray-Spira, R. (2019). Risk of Hematologic Malignant Neoplasms After Postoperative Treatment of Breast Cancer. Cancers, 11.","DOI":"10.3390\/cancers11101463"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Coyte, A., Morrison, D.S., and McLoone, P. (2014). Second primary cancer risk\u2014The impact of applying different definitions of multiple primaries: Results from a retrospective population-based cancer registry study. BMC Cancer, 14.","DOI":"10.1186\/1471-2407-14-272"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1829","DOI":"10.1016\/S0959-8049(97)00173-1","article-title":"Incidence of second primary cancers in three Italian population-based cancer registries","volume":"33","author":"Buiatti","year":"1997","journal-title":"Eur. J. Cancer"},{"key":"ref_6","first-page":"1231","article-title":"The effect of multiple primary rules on population-based cancer survival","volume":"24","author":"Weir","year":"2013","journal-title":"Cancer Causes Control"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"124","DOI":"10.1159\/000475142","article-title":"Benign Renal Tumors Detected among Healthy Adults by Abdominal Ultrasonography","volume":"27","author":"Fujii","year":"1995","journal-title":"Eur. Urol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2795","DOI":"10.7150\/jca.25482","article-title":"Multiple Primary Malignant Tumors\u2014A 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":"ref_9","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1634\/theoncologist.12-1-20","article-title":"Cancer Statistics, Trends, and Multiple Primary Cancer Analyses from the Surveillance, Epidemiology, and End Results (SEER) Program","volume":"12","author":"Hayat","year":"2007","journal-title":"Oncologist"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2895","DOI":"10.7150\/jca.24749","article-title":"Clinicopathological and prognostic significance of leucine-rich repeats and immunoglobulin-like domains protein 1 (LRIG1) in malignant tumors: A meta-analysis","volume":"9","author":"Zhang","year":"2018","journal-title":"J. Cancer"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1038\/s41572-024-00529-7","article-title":"Multiple myeloma","volume":"10","author":"Malard","year":"2024","journal-title":"Nat. Rev. Dis. Primers"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"464","DOI":"10.1001\/jama.2022.0003","article-title":"Diagnosis and management of multiple myeloma: A review","volume":"327","author":"Cowan","year":"2022","journal-title":"JAMA"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"17046","DOI":"10.1038\/nrdp.2017.46","article-title":"Multiple myeloma","volume":"3","author":"Kumar","year":"2017","journal-title":"Nat. Rev. Dis. Primers"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1111\/imr.12389","article-title":"Monoclonal antibodies targeting CD 38 in hematological malignancies and beyond","volume":"270","author":"Janmaat","year":"2016","journal-title":"Immunol. Rev."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Trisal, D., Kumar, N., Sundriyal, D., and Gadpayle, A.K. (2014). Hypercalcaemia of malignancy: Two primaries in the same patient. BMJ Case Rep., 2014.","DOI":"10.1136\/bcr-2014-204368"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"509530","DOI":"10.1155\/2010\/509530","article-title":"Metastatic Breast Cancer or Multiple Myeloma? Camouflage by Lytic Lesions","volume":"2010","author":"Hough","year":"2010","journal-title":"J. Oncol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"231","DOI":"10.1016\/j.currproblcancer.2017.11.001","article-title":"Breast cancer and synchronous multiple myeloma as a diagnostic challenge: Case report and review of literature","volume":"42","author":"Mazur","year":"2018","journal-title":"Curr. Probl. Cancer"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"NP14","DOI":"10.1177\/03008916231176586","article-title":"Complete pathological response of hormone receptor positive invasive breast cancer in a patient with multiple myeloma treated with ixazomib","volume":"109","author":"Dameri","year":"2023","journal-title":"Tumori J."},{"key":"ref_19","first-page":"e96191","article-title":"Not All Bone Lesions After Breast Cancer Treatment Indicate Metastasis: A Case Report and Review of the Literature","volume":"17","author":"Kaakoua","year":"2025","journal-title":"Cureus"},{"key":"ref_20","first-page":"e48880","article-title":"Challenging Diagnosis of Lytic Bone Lesions Between Multiple Myeloma and Bone Metastasis of Primary Breast Cancer","volume":"15","author":"Edahiro","year":"2023","journal-title":"Cureus"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"e46540","DOI":"10.1097\/MD.0000000000046540","article-title":"Multiple myeloma in a man with breast cancer: A case report and literature review","volume":"104","author":"Zhou","year":"2025","journal-title":"Medicine"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"e30320","DOI":"10.1097\/MD.0000000000030320","article-title":"A case report of secondary synchronous diagnosis of multiple myeloma and systemic lupus erythematosus after breast cancer treatment: A CARE-compliant article","volume":"101","author":"Chen","year":"2022","journal-title":"Medicine"}],"container-title":["Current Oncology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1718-7729\/33\/8\/473\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,11]],"date-time":"2026-08-11T09:18:07Z","timestamp":1786439887000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1718-7729\/33\/8\/473"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,10]]},"references-count":22,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2026,8]]}},"alternative-id":["curroncol33080473"],"URL":"https:\/\/doi.org\/10.3390\/curroncol33080473","relation":{},"ISSN":["1718-7729"],"issn-type":[{"value":"1718-7729","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,10]]}}}