Invasive keratoacanthoma of the eyelid and ocular adnexa

PURPOSE: To report three patients with superficially invasive crateriform squamous proliferations of periocular tissue. METHODS: The authors identified three patients with superficially invasive periocular tumors that had clinical features of keratoacanthoma. Clinical histories, radiographs, and surgical pathologic specimens were reviewed. RESULTS: All three tumors arose over several weeks, had a crateriform configuration, and exhibited superficial invasion of underlying tissues, including perineural invasion and infiltration into skeletal muscle. All three tumors were classified as invasive keratoacanthoma. One tumor exhibited late perineural extension into the cavernous sinus and convincing histologic features consistent with squamous cell carcinoma. CONCLUSION: The clinical importance of recognizing invasive keratoacanthoma is that although the tumor has the potential for spontaneous involution, locally aggressive behavior with deep perineural invasion is possible. This tumor is considered to represent a variant of squamous cell carcinoma. The authors recommend complete surgical excision of crateriform squamous proliferations with frozen section control of margins of resection.