Kim and Abramson excision, and with topical interferon alone, 5 of 7 patients were successfully treated. Two patients experienced clinical recurrences, noted at 2 months and 1 year of follow-up, and in both cases, topical therapy was re-instituted. The average duration of treatment in this series was 14.1 weeks, and the average period to resolution of disease was 14.5 weeks (range, 5–24 weeks). Ocular side effects were not observed in any of these patients. Summary of OSSN and topical agents For the treatment of both preinvasive and invasive OSSN lesions, topical MMC and 5-FU have been shown to be effective when used as primary therapy. A comparative trial has not been performed between these two agents, and it is therefore difﬁcult to compare clinical results between various series. Topical MMC has a longer track record, and it may prove be more versatile, since it has been used as primary therapy, as a preoperative neoadjuvant agent, and a postop- erative therapy to decrease recurrence rates. 5-FU appeared to have slightly higher recurrence rates in earlier studies, but the paper by Midena and colleagues (2000) clearly showed that topical 5-FU was very effective in the primary treatment of invasive SCC. When considering both MMC and 5-FU, recurrences respond quite well to second and third courses of topical treatment, and few patients require surgical inter- vention. Overall, patients treated with 5-FU may experience fewer side effects than MMC during the treatment course, although permanent ocular toxicity with MMC has not been reported when treating OSSN lesions. Topical interferon may play a role in patients who are intolerant of topical che- motherapeutic agents, although the number of cases treated successfully with this therapy is small and prolonged courses of treatment are required (minimum of 3–4 months). Pagetoid spread of sebaceous cell carcinoma Sebaceous gland carcinoma of the periocular region may present with pagetoid extension of the conjunctiva in 41%–80% of cases (Kass and Hornblass 1989). Despite the common practice of using map biopsies to deﬁne the extent of pagetoid extension, surgical eradication of the tumor is complicated by the ill-deﬁned and multifocal nature of the intraepithelial involvement in many patients with sebaceous cell carcinoma (Putterman 1986). Kemp and colleagues (2002) reported treating two patients with pagetoid exten- sion from sebaceous cell carcinoma with topical MMC; in one case MMC 0.04% was used as a preoperative adjunct before surgical excision, and in the second case, topical 512 MMC was used both intraoperatively and postoperatively. The second patient developed a clinical recurrence which was treated with another course of topical MMC 0.04% and a subsequent biopsy 22 months later showed no evidence of disease. Shields and colleagues (2002) presented a series of 3 patients with pagetoid invasion of the conjunctiva treated successfully with topical MMC. After conﬁrmation of dis- ease by map biopsies, patients were started on topical MMC 0.04% with 7 day cycles; the exact duration of treatment was not reported although the authors commented that treatment courses were repeated until all epithelial disease was judged to be clinically regressed. None of the three patients appeared to suffer from a recurrence, and two of the cases had negative post-treatment biopsies, although the longest follow-up was only 17 months. It should be emphasized that topical MMC should only be used in selected cases of biopsy conﬁrmed sebaceous cell carcinoma as a surgical adjunct for pagetoid extension. In such cases, patients can be treated with topi- cal MMC for residual intraepithelial disease following wide surgical excision of the tumor mass. Caution is also warranted when considering MMC in any patient who has undergone extensive eyelid reconstruction, given that compromised eyelid function is likely to be accompanied by ocular surface abnormalities. It is also important to delay topical treatment until all surgical wounds are healed, to avoid more serious ocular side effects related to wound healing or intraocular penetration of the drug. Tumuluri and colleagues (2007) reported signiﬁcant corneal complications in a 78 year old man with pagetoid invasion of the conjunctiva treated with topical MMC (Tumuluri et al 2004). Following wide tumor excision and complete upper lid reconstruction, the patient was treated with a total of six weeks of topical MMC 0.02% four times a day for epithelial disease. Although the patient was recurrence-free at two years of follow-up, his course was complicated by corneal epithelial toxicity and ulceration requiring lateral tarsorrhaphy. Complications of ocular topical therapy Ocular toxicity of MMC Almost all patients treated with topical MMC experience transient side effects, manifesting as conjunctival injection, chemosis, and/or keratitis (Demirci et al 2000; Frucht-Pery et al 2002; Kurli and Finger 2005; Khong and Muecke 2006). In Kurli’s series, all patients who were treated for 28 days developed keratoconjunctivitis, which took 4–6 weeks to resolve (Kurli and Finger 2005). It is not uncommon for Clinical Ophthalmology 2008:2(3)