Through the Cracks: Diagnostic Dilemma of Cystic Hypersecretory Hyperplasia in a Limited Breast Sample

We describe a diagnostically challenging case of cystic hypersecretory hyperplasia (CHH), an exceptionally rare benign breast lesion that is often difficult to distinguish from more aggressive pathologies. The patient, an asymptomatic woman in her sixth decade, was identified during routine breast screening. Imaging evaluation revealed conflicting findings: mammography demonstrated features that raised suspicion for malignancy, whereas ultrasound appearances were more compatible with a benign process. Clinical assessment offered no additional clarity, underscoring the complexity of the diagnostic workup. Histological confirmation proved equally challenging. The initial needle core biopsy specimen provided insufficient material for a definitive diagnosis, necessitating a second biopsy. Only after this additional sampling was the lesion accurately classified as CHH. This case illustrates the diagnostic limitations of small-volume tissue sampling, particularly in rare entities with subtle histological features. Although CHH typically lacks cytological atypia, its recognized association with atypical and malignant variants-including cystic hypersecretory carcinoma-supports its categorization as a lesion of uncertain malignant potential. Consequently, surgical excision remains the preferred management approach, even in the absence of overt atypia, to exclude coexistent or progressive disease. This report emphasizes the critical role of multimodal imaging, repeated histopathological evaluation when necessary, and a cautious surgical strategy to ensure accurate diagnosis and safe patient management in rare breast lesions with ambiguous presentations.