Papillary ductal proliferations: sialadenoma papilliferum family of tumors and inverted ductal papillomas.

Papillary ductal proliferations of the salivary glands encompass a spectrum of benign neoplasms and reactive conditions. The present review will focus on the sialadenoma papilliferum (SP) family of tumors and inverted ductal papillomas (IDP). Intraductal papilloma is a rare salivary gland lesion with poorly defined diagnostic criteria, significant overlap with more reproducible entities, and histologic features distinct from SP and IDP, and is therefore excluded from this review. The SP family of tumors comprises conventional SP, SP-like intraductal papillary tumor, and tubulopapillary hidradenoma-like tumor of the mandible, is characterized by a consistent small ductal proliferation and a variable exophytic component, and is often driven by BRAF p.V600E mutations. Inverted ductal papillomas exhibit a distinct endophytic growth pattern reminiscent of their sinonasal counterparts but are restricted to the salivary ducts. While generally indolent, these tumors can mimic malignant entities such as intraductal carcinoma, mucoepidermoid carcinoma, or squamous cell carcinoma. Accurate diagnosis is essential to ensure appropriate conservative management and avoid unnecessary treatment. This review provides an overview of the clinical, histopathological, and molecular features of these papillary ductal proliferations, outlining key diagnostic criteria to distinguish them from their mimics.