Abstract

Background: Intraductal carcinoma (IDC) is a rare salivary gland malignancy characterized by distinctive histopathological, immunohistochemical, and molecular features. However, in routine pathology practice, the diagnosis of IDC can be challenging because of its morphologic and immunophenotypic overlap with other salivary gland tumors, particularly secretory carcinoma (SC). Histologic features such as cystic and glandular structures containing secretory material, together with the expression of S100, SOX10, and mammaglobin, may be observed in both entities. In the absence of molecular testing, the accurate classification of tumors with atypical features may therefore represent a significant diagnostic challenge. We report a case of intraductal carcinoma of the parotid gland showing histologic and immunohistochemical features suggestive of secretory carcinoma, highlighting potential diagnostic pitfalls and emphasizing the importance of an integrated approach incorporating histopathology, immunohistochemistry, and molecular analysis whenever available. Case Presentation: A 54-year-old man presented with a slowly enlarging right parotid mass that had progressed over a two-month period. Computed tomography (CT) of the maxillofacial and neck region revealed multiple lesions within the right parotid gland, with ill-defined margins and focal cystic components, the largest measuring approximately 38 × 25 mm. The patient underwent right parotidectomy. Histopathological examination demonstrated a neoplasm with morphologic and immunohistochemical features suggestive of the coexistence of intraductal carcinoma and secretory carcinoma. Conclusion: This case underscores the limitations of standard histopathological and immunohistochemical criteria in classifying rare salivary gland cancers. An integrated diagnostic approach combining detailed microscopic evaluation, comprehensive immunophenotyping, and, when accessible, molecular testing is essential to ensure an accurate diagnosis and optimize patient management.