Challenges in pathological diagnosis of rare head and neck cancers: National survey and retrospective study.

Purpose: The complexity of head and neck cancers (HNC) makes histopathological diagnosis challenging, mainly for rare histotypes (r-HNCs) where a second opinion (2°op) is often required.

Methods: In 2023, the Italian Association of Head and Neck Oncology (AIOCC) young task force conducted a 17-item survey on HNC multidisciplinary management and pathological diagnosis. A retrospective review was performed on r-HNC cases evaluated in the last 10 years by an HNC expert pathologist at a referral center. Major diagnostic discrepancies (MDD), defined as changes in pathological diagnosis that significantly influenced clinical management, were analyzed.

Results: Among the 30 surveyed participants, 67% sought a 2°op for r-HNC, often leading to changes in diagnosis or treatment. In 130 reviewed cases, 66% had no initial pathological diagnosis; of the remaining 34% (44) with a previous diagnosis, 50% were changed after the review. Minor salivary gland tumors of the oral cavity (57%) had the highest rate of MDD, followed by the sinonasal tract (43%). 14% (6) involved only descriptive diagnosis reformulation/reclassification whereas of MDD (16%,7), 29% involved a change from benign to malignant, 14% a change from malignant to benign.

Conclusions: According to the complexity of HNC district, a second opinion is often needed and when a preliminary histopathological diagnosis was formulated, a MDD results in 16%. An effective diagnostic network among HNC pathologists is warranted.