# A rare case report of triple primary malignancies: synchronous breast ductal invasive carcinoma and lung neuroendocrine tumor, followed by chronic myeloid leukemia

## TL;DR

A 59-year-old woman developed three different cancers—breast, lung, and leukemia—highlighting the rare and complex nature of multiple primary malignancies.

## Contribution

This is the first reported case of triple primary malignancies involving breast IDC, lung NET, and subsequent CML.

## Key findings

- IDC and lung NET were confirmed as independent primary tumors through histopathology and immunohistochemical analysis.
- The patient later developed CML, adding complexity to the management of multiple malignancies.
- The case emphasizes the need for thorough diagnostics to distinguish MPMTs from metastatic disease.

## Abstract

Multiple primary malignancies (MPMTs), the occurrence of two or more different primary cancers in a single person, are rare. These tumors can be synchronous or metachronous, with an incidence ranging from 0.73 % to 11.70 % in cancer patients. While invasive ductal carcinoma (IDC) is the most common form of breast cancer and lung neuroendocrine tumors (NETs) are rare, their co-occurrence as MPMT is extremely rare. In addition, chronic myeloid leukemia (CML) makes such cases even more complex.

We report the case of a 59-year-old woman who presented with a lump in the left breast. Diagnostic examinations confirmed breast IDC. Metastatic examination identified a separate primary, well-differentiated NET of the left lung. Both malignancies were treated surgically followed by appropriate adjuvant therapy. A year later, routine follow-up revealed an elevated white blood cell count and a subsequent bone marrow biopsy confirmed the diagnosis of CML.

The diagnosis of IDC and pulmonary NET as primary tumors is rare and the subsequent development of CML in this setting has not been reported previously. This case highlights the critical importance of thorough diagnostic evaluations to accurately differentiate between metastatic disease and MPMTs. The occurrence of three different malignancies in a single patient presents significant treatment challenges and highlights the need for personalized treatment approaches.

This report emphasizes the need for comprehensive diagnostic protocols in the evaluation of multiple tumors and contributes to the growing body of knowledge about MPMT. The coexistence of IDC, pulmonary NET and subsequent CML represents a rare and complex clinical scenario that requires continuous research into optimal management strategies for such cases.

•Multiple Primary Malignant Tumors (MPMTs) are rare, with synchronous or metachronous presentations occurring in 0.73%-11.70% of cancer patients.•This case describes an unusual combination of invasive ductal carcinoma (IDC) of the breast, a lung neuroendocrine tumor (NET), and subsequent chronic myeloid leukemia (CML).•Diagnostic evaluations distinguished IDC and NET as independent primary malignancies, confirmed by histopathology and immunohistochemical analysis.•The development of CML during follow-up highlights the complexity of managing triple malignancies and the importance of personalized treatment plans.•This report underscores the necessity of thorough diagnostic workups to differentiate between metastatic disease and MPMTs, contributing to the understanding of these rare clinical scenario

Multiple Primary Malignant Tumors (MPMTs) are rare, with synchronous or metachronous presentations occurring in 0.73%-11.70% of cancer patients.

This case describes an unusual combination of invasive ductal carcinoma (IDC) of the breast, a lung neuroendocrine tumor (NET), and subsequent chronic myeloid leukemia (CML).

Diagnostic evaluations distinguished IDC and NET as independent primary malignancies, confirmed by histopathology and immunohistochemical analysis.

The development of CML during follow-up highlights the complexity of managing triple malignancies and the importance of personalized treatment plans.

This report underscores the necessity of thorough diagnostic workups to differentiate between metastatic disease and MPMTs, contributing to the understanding of these rare clinical scenario