Keratoacanthoma of the inferior lip: review and report of case with spontaneous regression

Abstract

Keratoacanthoma (KA) is a self-limited benign epithelial proliferative lesion that eventually presents with very similar clinical features to squamous cell carcinoma. Many KA appear in the vermilion border of the lips and therefore dental professionals must be familiar of the disease. This article reports the case of a 40-year-old female patient presenting with an exophytic ulcerative tumor in her lower lip that resolved after incisional biopsy. Photographic documentation of the case is presented and topics that are relevant to the clinical management of the disease are addressed.

FIGURE 1. Initial aspect of the patient, showing a nodular exophytic lesion in the inferior lip, with superficial ulceration and partial brown-pigmented crust covering

FIGURE 2. Representative aspects of the histological features observed in the initial biopsy. A Low-power view of the tissue section presenting epithelial proliferation and apparent invasion of the lamina propria in one of the fragment borders (arrow). [Hematoxylin-eosin stain, scale-bar = 1mm] B Detail of epithelial projections observed in the specimen presenting acanthosis (white bar), abrupt keratin pearl formation (black arrow), mild cellular pleomorphism in the basal layer (black star), occasional mitosis (white arrow), and moderate infiltrate by inflammatory cells (white star). [Hematoxylin-eosin stain, scale-bar = 125 μm]

FIGURE 3. Clinical aspect of the lesion after the initial surgical intervention (biopsy), demonstrating partial regression compared to Figure 1

FIGURE 4. Final aspect of the patient, two months after the second biopsy, showing complete involution of the lesion without significant scarring