Cribriform adenocarcinoma of the tongue and minor salivary glands: a systematic review of an uncommon clinicopathological entity.

Introduction: Cribriform adenocarcinoma of the tongue and minor salivary glands (CATMSG) is a rare neoplasm, accounting for less than 1% of salivary gland tumors. In the past it has been considered a possible variant of polymorphous low-grade adenocarcinoma (PLGA), while nowadays it is accepted as a provisional entity in the WHO classification. The aim of this paper is to systematically review the existing literature about CATMSG with a particular attention to differential diagnosis and prognostic factors.

Methods: This study was performed in accordance with the PRISMA checklist. A comprehensive search in PubMed, Cochrane, and Google Scholar databases was carried out in June 2021, in partnership with a medical librarian, without time restriction. Search items include the following keywords: "cribriform adenocarcinoma of the tongue" OR "cribriform adenocarcinoma of the tongue and minor salivary glands."

Results: A total of 56 patients were evaluated. Patient age across the studies ranged from 13 to 85 years (mean 59.6 year). The most common site of involvement was the tongue (58.9%), followed by palate (19.6%), tonsil (7.1%), buccal (3.6%) and reticular mucosa (3.6%), lip (3.6%), retromolar pad (1.7%), and floor of the mouth (1.7%). Lymph node involvement at the diagnosis was very common (58.9%), while there was no evidence of patients diagnosed with metastatic disease. The most common surgical approach was surgical excision (17, 30.3%); neck dissection was performed in 16 patients (28%). Radiotherapy was the most common adjuvant treatment reported (46.4%); only one patient underwent adjuvant chemotherapy (1.7%). Five patients experienced a recurrence (8.8%).

Conclusion: To our knowledge, only 56 five cases of CATMSG have been previously described. The results of this review seem to confirm the low frequency of relapses and distant metastases, but we observed that almost 60% of cases presented with cervical lymph node involvement. In our opinion, CATMSG should be considered as a distinct tumor entity from PLGA.