A Novel Combination of Metachronous Primary Malignancies of the Thyroid and Breast in a Patient with Neurofibromatosis Type 1

Neurofibromatosis 1 (NF1) is a genetic condition of variable presentations. It has been shown to increase the risk of multiple cancers. Therefore, NF1 has been identified as a tumorprovoking condition. We present a case of a 39-year-old woman with NF1 who was diagnosed initially with papillary thyroid carcinoma (PTC) and subsequently presented with a painful breast lump. Core biopsy revealed an invasive ductal carcinoma (IDC) for which selective estrogen receptor modulator (SERM) therapy was initiated. A lumpectomy was performed soon after, which confirmed IDC. Following surgery, the patient received a combination of anthracycline and cyclophosphamide (AC), which was later followed by a taxol-based chemotherapy regimen. This study aims to throw light on the rare phenomenon of metachronous malignancy: the occurrence of successive primary cancers in the same patient. We believe that raising awareness regarding the different neoplasms associated with NF1 is important to promote appropriate preemptive screening for early detection of a second primary neoplasm, which can help lower the morbidity and mortality associated with this condition through expedited intervention.