Coexistence of Pregnancy-Like and Cystic Hypersecretory Hyperplasia with Invasive Lobular Carcinoma

Background: Lobular pregnancy-like hyperplasia (PLH) merged with cystic hypersecretory hyperplasia (CHH), designated PLH/CHH, is a rare multicystic breast lesion. A previous report has described the high rate of coexistent ductal carcinoma in situ in PLH/CHH; however, a PLH/CHH study involving a larger number of cases is necessary to unravel the clinical significance of this tumor type. Case Report: We describe a unique case of PLH/CHH that coexisted with multifocal lobular neoplasm. Multifocal invasive lobular carcinoma with lobular carcinoma in situ was observed to be adjacent to the PLH/CHH cystic lesions in the left breast of a 70-year-old woman. Conclusions: The present case documents the previously unreported coexistence of PLH/CHH accompanied by multifocal lobular carcinoma. Extensive examination, including an excisional biopsy, is prudent if a needle core biopsy reveals a PLH/CHH lesion.