Summary

A 57-year-old man presented in 2016 with a 4-month history of a right submandibular mass, having undergone left submandibular gland (SMG) excision in 2003. Imaging suggested a benign tumour and subsequent core biopsy findings suggested a nodular oncocytic hyperplasia, similar to the tumour removed from the contralateral side. This was confirmed on histological analysis following right submandibular gland excision which showed characteristic features of nodular oncocytic hyperplasia along with an unusual diffuse papillary cystadenoma-like ductal proliferation, similar to that seen in the 2003 specimen. A diagnosis of multinodular adenomatous oncocytic hyperplasia (MAOH) was rendered in order to communicate the unique histological features that have otherwise not been described in the literature. We believe that this is the first reported case of non-synchronous multinodular oncocytic hyperplasia and the first case affecting the submandibular glands.