Solitary annular lesion on the ventral tongue

A 60-year-old male patient was referred for evaluation of a well-circumscribed, asymptomatic lesion located on the right ventral tongue of unknown duration. His medical history was non-contributory other than clinically diagnosed psoriasis on his right lower extremity and face. The patient was edentulous and denied use of any removable prostheses. Intraoral examination revealed a circinate lesion with a slightly elevated pink and well-defined margin measuring 5.0 × 4.0 mm in the anterior right ventral tongue. The mucosa in the central portion of the lesion appeared normal (Figure 1). The patient did not report any pain, difficulty chewing or speaking and no history of trauma or surgery in the area. An excisional biopsy was performed under local anesthesia, and the specimen was sent for histopathological analysis. The correct diagnosis is C, porokeratosis. Histopathological analysis revealed parakeratinized squamous epithelium with two cornoid lamellae composed of parakeratotic columns present at either end of the specimen (Figure 2a). Dyskeratotic and vacuolated keratinocytes were present at the base of the cornoid lamellae (Figure 2b). Porokeratosis is an uncommon dermatologic disorder characterized by a clonal abherration of keratinocytes in the skin and/or oral mucosa which produces a well-defined, annular, elevated, hyperkeratotic marginal ridge (Errichetti, 2019). It usually presents on the skin of individuals in their fifth decade of life in equal distribution between sexes (Williams & Fillman, 2023). It is commonly seen as a genodermatosis, however, sporadic cases that arise due to somatic mutations have been reported (Williams & Fillman, 2023). There are multiple clinical variants of porokeratosis; porokeratosis of Mibelli, as shown in this case, is the second most common type (Williams & Fillman, 2023). Oral manifestations of porokeratosis are exceedingly rare, with less than 20 cases reported in the literature to date. Oral porokeratosis most commonly affects the labial and buccal mucosa of patients in the fourth decade of life, with a slight female predominance (Bhatia et al., 2017; Roson et al., 2001). Lesions in the oral cavity usually present as small asymptomatic annular plaques, similar to their dermatologic counterpart, and may or may not be associated with skin lesions. Histologically, porokeratosis shows one or multiple cornoid lamellae composed of a column of perakeratin. In sites that are usually orthokeratinized, the underlying granular cell layer is diminished or absent. Dyskeratotic and vacuolated keratinocytes can be seen in the spinus layer directly beneath the cornoid lamella (Patterson, 2016). The clinical relevance of this condition is highlighted by its increased risk for malignant transformation. Retrospective analyses have characterized the malignant transformation rate of porokeratosis within the range of 6.4%–16.4% (Novice et al., 2021; Sasson & Krain, 1996). Squamous cell carcinoma and basal cell carcinoma have been repeatedly shown to be the first and second most common types of skin cancer to arise within lesions of porokeratosis, respectively (Inci et al., 2023; Novice et al., 2021; Sasson & Krain, 1996). While the clinical course of the condition is more widely understood, much of our understanding of the pathogenesis remains unresolved. Keratinocytes in porokeratosis have been shown to overexpress p16 and p53, which have been hypothesized to be related to the disease's pro-oncogenic qualities (Magee et al., 1994; Uryu & Furue, 2017). None of the reported cases in the oral cavity have undergone malignant transformation to date. The patient healed after the excisional biopsy with no complications. He will return for a three-month follow-up appointment and will continue to be monitored at future visits. Maxwell E. Perelgut: Conceptualization; writing – original draft; writing – review and editing. Allison M. Lee: Conceptualization; writing – original draft; writing – review and editing. Ana Luiza O. C. Roza: Conceptualization; writing – original draft; writing – review and editing. Joshua C. Allen: Conceptualization; writing – original draft; writing – review and editing. John M. Wright: Supervision; conceptualization; writing – original draft; writing – review and editing. The authors have nothing to report. All authors have no conflicts of interest to disclose. The patient reported in this manuscript provided written informed consent for the publication of the case details. Data sharing not applicable to this article as no datasets were generated or analysed during the current study.