for exenteration are involvement of the globe or anterior third of the orbit by infiltrative tumor, and widespread irreparable involvement of the bulbar conjunctiva [17]. In our review, the rate of exenteration was 10.5% (6 of 57). The overall rate of exenteration in SC ranges from 13% (8 of 60) [45] to 23% [55].

26.5.10 Mohs Surgery, Practical Points

In the typical Mohs surgery practice, the treatment of a sebaceous carcinoma is intercalated among other Mohs cases. Schedule a presurgical consult to assess the tumor and coordinate dermatopathology and oculoplastic care, with a 1-week delay for paraffin sections with possible immunohistochemistry stains. A primary SC tumor of short duration that is limited to either the upper lid or lower lid usually can be excised in one to two Mohs layers without disruption of the clinic schedule. A recurrent tumor or a SC that involves the either canthus or conjunctiva requires more detailed planning. Frequently, frozen sections are used to determine the preliminary margin, followed by a final layer for paraffin sections to double check the epithelial margin. If possible, a complex SC case should not be scheduled on a very busy day. Ocular cases require time to excise tumor and carefully read microscopic slides. Do not hurry microscopic analysis for the sake of a reconstruction deadline. If there are confusing inflammatory cells, double check results with another layer, or send defrosted specimen for paraffin sections. Delay repair if needed because a recurrence can lead to orbital involvement and exenteration. After excision, take time to orient and flatten tissue specimens properly. Mucous epithelium folds over easily, and pagetoid cells are more difficult to recognize through folded tissue sections. Hand-deliver specimens to the technician and indicate the mucous epithelium site that needs to be sectioned. If dermatopathology service is available, consider taking an additional epithelial layer for fast-track paraffin sections. Similarly, escort the specimens into the lab and indicate the mucosal side so that the technician can flatten the specimens in the cassette. The Mohs surgeon should be prepared to perform corneal protective repair.

26.5.11 Corneal Protection Measures

Since reconstruction is often delayed while waiting for paraffin section results, the cornea may be protected

from injury in several ways. These protective measures include: (1) sterile ophthalmic ointment, nonirritating contact layer, and eye pad; (2) a moist plastic chamber to cover the eye; and (3) temporary tarsorrhaphy [17].

Summary: Follow-Up Considerations

•Traditional wide local excision resulted in local recurrence of 18%, regional metastasis of 8%, and 6% deaths.

•Our updated review accumulated 57 patients treated with Mohs micrographic surgery; the overall local recurrence rate following Mohs surgery was 12.3% (7 of 57), regional metastasis 8.8% (5 of 57), and no deaths. The Mohs surgery local success rate for primary and recurrent sebaceous carcinoma was 88% and 70%, respectively. These results compare favorably to traditional wide local excision.

•Sentinel lymph node has been used in some patients of sebaceous carcinoma.

•Long-term follow-up is warranted for patients treated with either traditional wide local excision or Mohs surgery.

26.6Follow-Up Considerations

Mohs surgery for SC has not yet achieved the high cure rate of basal and squamous cell carcinoma. Local recurrence is about 12% and if not recognized early is attended with exenteration and lymph node metastasis [31]. All SC patients should be followed at least 5 years, longer if possible (see below).

26.6.1 Local Recurrence

Table 26.1 updates the previous 2002 review that accumulated 49 cases of SC treated by Mohs surgery [31]. Eight additional cases were added yielding a total of 57 cases. There were 17 males, 39 females, and 1 not stated. Age range was 31–94, mean 70.4 years. The eyelid distribution was upper (n = 35), lower (n = 17), canthi (n = 4), and caruncle (n = 1). There were seven local recurrences achieving a local success rate of 87.7%. The local success

rate for primary and recurrent tumors was 86% and 77%, respectively. This case updates the multicentric incidence of 5.4% in Mohs surgery cases. In total, six of seven local recurrences were treated by exenteration. The average time for local recurrence was 10 months, range from 1 to 19 months. However, recently, Callahan [42] reported a local recurrence at 71 months post Mohs (see Table 26.2). Using WLE, Shields et al. [45] reported a local recurrence of 18% (11 of 60) at 16 months, and of these 3 of 11 (27%) were assessed to be of multifocal origin, developing in new sites not previously involved with tumor.

26.6.2 Metastasis

Following Mohs surgery, there were five regional node metastases, yielding a metastatic rate of 8.8% (5 of 57). Four of these metastases from the 2002 paper are reviewed here. Since 2002, a single case was added from Arora et al. [41]. This was a 57-year-old woman with a recurrent chalazion of the upper lid treated by

curettage for about 1.5 years. The tumor was excised using paraffin sections. At the time of reconstruction, a preauricular cheek lymph node was noted. A fine need aspiration confirmed metastatic SC. The patient had a total parotidectomy, neck dissection, and radiation. The patient was NED for 3 years. From the 2002 review, there were 4 other patients with regional metastases: (1) a primary SC of the caruncle (a high risk anatomic site) metastasized to the submandibular and neck nodes at 1 month post Mohs [15]; (2) a recurrent tumor of the upper lid of 4 years duration, metastasized to the neck at 10 months, and was treated by surgery and radiation [17]; (3) a tumor that involved both lids, metastasized to the parotid nodes at 9 months [56]; and (4) a patient with long-standing chronic blepharitis was misdiagnosed as SCC in situ and developed a submandibular lymph node while undergoing Mohs surgery [31]. Mohs surgery confirmed orbital spread requiring exenteration. The patient was followed for 1 year then lost to follow-up [31]. Shields et al. [45] reported a regional metastasis rate of 8% (5 of 60) and death rate of 6%.