Purpose: To describe an acquired, smooth white lesion of the caruncle and to underscore the role of subsurface keratinizing squamous epithelium in its formation.
Methods: Clinical photographic documentation, histopathologic evaluation, and immunohistochemical staining of an excised specimen from a 25-year-old woman.
Results: A cyst was found that was lined by keratinizing squamous epithelium without a keratohyaline layer (trichilemmal keratinization), typical of lesions of the pilosebaceous unit. A portion of the cyst's lining was replaced by granulomatous inflammation resulting from an earlier spontaneous partial rupture. Ki-67 immunolabeling demonstrated relatively few nuclei in S-phase (DNA synthesis) in comparison with the overlying epithelium, thereby suggesting an obstructive, nonproliferative cause for the cyst.
Conclusion: A white caruncular lesion is a very rare finding according to the literature. It is most likely caused by a cyst lined by squamous epithelium elaborating trichilemmal-type keratin. A sebaceous gland duct was established as the source for the current lesion.