Oncocytic Chondro-Osseous Respiratory Epithelial Hamartoma: Expanding the Histological Variants of CORE Hamartoma and Literature Review

Chondro-osseous respiratory epithelial (CORE) hamartoma is a rare sinonasal lesion and is considered a benign tumor-like lesion. However, a growing body of evidence suggests that CORE hamartoma may represent a benign neoplasm which could potentially undergo malignant transformation. An oncocytic variant of CORE hamartoma has not yet been described. Herein, we present the first case of oncocytic CORE hamartoma in an 85-year-old patient. We summarize the current state of knowledge on CORE hamartoma, including epidemiological/clinical, histopathological and immunohistochemical findings, and discuss potential diagnostic pitfalls that may lead to erroneous diagnosis.