The pigmentation of the fungiform papillae of the tongue is a rare idiopathic condition in which only the fungiform papillae appear hyperpigmented. In the absence of any reviews on the subject, we conducted a systematic review of the aetiopathogenesis and pathophysiology of pigmented fungiform papillae (PFP) of the tongue, including its demographic and histopathological features, trying to outline a possible aetiology. The preferred reporting items for systematic reviews and meta-analyses (PRISMA) was performed using PubMed, Scopus, EMBASE databases and manual searches, for publications between January 1974 and July 2022. Inclusion criteria were case reports defining patients’ characteristics, their general medical and dental conditions, histopathological and/or immunohistochemical findings, all with a final definitive diagnosis of PFP. Overall, 51 studies comprising 69 cases of PFP which included histopathological descriptions were reviewed. Prominent features consisted of hyperpigmentation of melanocytes, melanophages, chromatophores, and a lymphocytic infiltrate in the subepidermal area of the fungiform papillae. On special staining, PFP contained melanin, not iron or hemosiderin. On immunohistochemistry, immune-reactive CD3+ T lymphocytes, S-100 and Sox10, but non-immune-reactive melan-A intraepithelial melanocytes were noted in some studies. The presence of hyperpigmented melanocytes and melanophages, with non-immune-reactive melan-A, suggests that PFP are a benign and physiological form of pigmentation. The inflammatory infiltrates described in some papillary lesions could possibly be due to traumatic events during mastication. Nevertheless, the true reasons for the hyperpigmentation of the fungiform papillae are as of yet elusive, and remain to be determined.

Background: Oral cancer therapy, such as radiation or surgical treatment, has pernicious long-term effects that patients suffer throughout their life, the disability being considerable with delayed diagnosis. It is well known that many oral cancers develop from oral potentially malignant disorders (OPMDs). Patients diagnosed with OPMDs may have an increased risk of developing cancer anywhere in the oral cavity. Early detection and intervention could be essential prevention strategies to inhibit oral cancer progression. OPMDs may not immediately develop into carcinoma. However, this condition provides a “field” of specific abnormalities wherein evolving altered genetic cells can be explained with the “field cancerization” concept. Purpose: This review aims to describe the “field cancerization” concept in oral cancer and OPMD, which is expected to contribute to a better clinical management strategy for oral cancer prevention. Review: “Oral field cancerization” describes oral cancers that develop in multifocal areas of pre-cancerous changes. It can be found as histologically abnormal tissue surrounding the tumor, suggesting that oral cancer often consists of multiple independent lesions. Conclusion: The oral field cancerization concept should prompt healthcare professionals to remind their patients that frequent oral examination with histological studies and molecular testing is mandatory for those at high risk of developing malignancies.