The diagnostic challenge of a Papillary lesion of the breast in a patient with Peutz-Jeghers syndrome

Abstract Introduction/Objective Peutz-Jeghers syndrome (PJS) is an autosomal dominant disorder with elevated risk of various neoplasms, including breast cancer. The incidence of cancer among PJS patients is estimated to be 15-fold higher than the general population. The spectrum of breast lesions in PJS varies from benign papillomas to invasive carcinomas, presenting significant diagnostic complexities. The case presented here revolves around a unique papillary lesion in a PJS patient. Methods/Case Report A 40-year-old African American female, with PJS presented with a palpable abnormality in the right subareolar region with sanguineous nipple discharge. Multiple prior biopsies revealed intraductal papillomas with no atypia. Imaging showed a 7.0 cm complex solid and cystic subareolar mass, which had increased in size by 42% within a short period. Given the rapid increase in size, malignant transformation was clinically suspected. The patient underwent bilateral mastectomy. Macroscopic examination showed a 9.0 cm tan firm subareolar nodule with solid and cystic components. Histopathology revealed areas consistent with intraductal papilloma, however, additional complexities, including epithelial and myoepithelial proliferations with mild cytologic atypia, squamous, apocrine, and sebaceous metaplasia made the diagnosis challenging. No necrosis or increased mitotic activity was identified. Immunostaining for CK5/6 and p63 highlighted the myoepithelial layer, while estrogen receptor demonstrated heterogeneous positive staining. This picture raised suspicion of adenomyoepithelioma, but there was a significant overlap with intraductal papilloma. A final diagnosis of intraductal papillary neoplasm with epithelial and focal myoepithelial atypia was rendered. Results (if a Case Study enter NA) NA Conclusion This case presented a complex diagnostic dilemma. The rapid growth of the lesion, coupled with cytological atypia, raised significant concern necessitating precise differentiation between adenomyoepithelioma and intraductal papilloma. Further research is imperative to explore the pathophysiology of breast lesions in PJS, their impact on surveillance, management, potential for malignancy, and prognosis. Investigating additional diagnostic modalities and molecular markers to aid in accurate differentiation between benign and malignant papillary neoplasms in PJS patients warrants consideration.