Diagnostic Usefulness of LC-OCT in Mammary and Extramammary Paget Disease and Correlation With Vertical and Horizontal Histopathology: A Case Series

The Paget disease represents a form of adenocarcinoma arising in epidermis; it can be distinguished in mammary (when involves the nipple areolar epidermis) and extramammary Paget disease (uncommon form that involves apocrine gland-rich areas); they present significant diagnostic challenges because of its nonspecific clinical appearance and frequent misidentification as benign, inflammatory skin conditions. Line-field confocal optical coherence tomography (LC-OCT) is a novel, noninvasive imaging modality that enables in vivo, real-time visualization of the skin with near-histological resolution. The objective of this study was to evaluate the diagnostic performance and clinical applicability of LC-OCT as a noninvasive imaging tool for the in vivo assessment of both mammary and extramammary Paget disease, and to establish their correspondence with conventional histopathological findings. This retrospective study included 4 patients with histopathologically confirmed diagnoses of mammary and extramammary Paget disease. All lesions were imaged in vivo with LC-OCT before biopsy. In both mammary Paget disease and extramammary Paget disease, LC-OCT identified intraepidermal clusters and single hypo-reflective Paget cells correlating with histological findings. LC-OCT represents a valuable adjunct in dermatologic diagnostics, offering near-histological, real-time visualization of cutaneous architecture. It can enhance diagnostic accuracy, guide biopsy site selection, improve preoperative margin assessment, and support follow-up after nonsurgical therapy.