Palisading Adenocarcinoma: A Morphologically Unique Salivary Gland Tumor With a Neuroendocrine-like Appearance and a Predilection for the Sublingual Glands of Women

[Salivary gland tumors: 2022 WHO blue book and beyond]

In 2022, the 5th edition of the WHO classification of Head and Neck tumors was published online. In the salivary gland chapter, a new benign entity, the keratocystoma, was introduced. The sclerosing polycystic adenosis has been recognized as tumoral and is now termed sclerosing polycystic adenoma. The striated duct adenoma now has its own dedicated chapter. Additionally, a new variant of pleomorphic adenoma, termed "canalicular adenoma-like," has been incorporated. Regarding malignant tumors of the salivary glands, significant doubts now exist regarding the actual existence of oncocytic carcinoma, which has been reclassified among emerging entities. Two new malignant entities have also emerged: microsecretory adenocarcinoma and microcystic sclerosing adenocarcinoma. Finally, primary mucinous adenocarcinoma of the salivary glands has been acknowledged as a distinct entity.

Palisading adenocarcinoma. Case report on a newly recognized tumor in the salivary glands

A palisading adenocarcinoma arising in the left submandibular salivary gland in a 65-year old woman is presented here. This tumor has been identified only very recently and its recognition as a true entity in the list of salivary gland tumors is still pending. Its distinct clinical-pathological context includes a predilection for women, sublingual or submandibular gland involvement, low-grade cytology with pseudo-neuroendocrine features, and sharp immunohistochemical expression.