Orbital and periorbital microcystic adnexal carcinoma

Purpose: To review the clinical and histopathologic features of patients with microcystic adnexal carcinoma of the orbital and periorbital tissue. Methods: This study was designed as a noncomparative interventional case series of three patients seen and treated at two oculoplastic surgical departments and a review of the literature. Clinical presentation, histopathologic findings, outcome of surgery, and clinical recurrence are presented. Results: Three patients underwent surgery for lesions temporal to the lateral canthus. All had initial histopathology diagnosed as squamous cell carcinoma but were subsequently diagnosed as microcystic adnexal carcinoma after clinical recurrence. All patients had multiple recurrences and extensive perineural spread. Two patients required radiotherapy. Conclusions: Review of the literature shows that microcystic adnexal carcinoma affecting the orbital and periorbital tissues is difficult to differentiate clinically and microscopically from other conditions including squamous cell carcinoma. Eighty-one percent of cases that have histopathology checked in the initial assessment are still misdiagnosed. A high degree of suspicion is necessary if the lesion extends beyond an apparently adequate surgical margin, multiple recurrences occur, or superficial perineural spread is present. Mobs technique is the treatment of choice and may be improved if paraffin sections or immunohistocytochemistry are performed. Wide excision should be carried out once clear margins are obtained. Radiotherapy may be necessary in cases with multiple recurrences.