Mohs Micrographic Surgery for Lentigo Maligna and Lentigo Maligna Melanoma using Mel-5 Immunostaining: University of Minnesota Experience

Abstract

MMS with Mel-5 immunostaining yielded excellent results in the treatment of LM and LMM, with only one recurrence noted in 200 patients. When an automated immunostainer was used, minimal time was added to each Mohs stage.

Staged excision versus Mohs micrographic surgery for lentigo maligna and lentigo maligna melanoma

“…This is comparable to the number of stages reported in other studies (range: 14-2.7) using various techniques. 10,11,13,14,19,24 The initial lesion sizes and postoperative defect sizes were similar in our retrospective analysis comparing the two techniques, with the final defect sizes similar to another study using a staged technique 14 and smaller than another study using MMS. 13 Thus, our staged technique may offer smaller surgical defects with similar margin control and stage number, likely leading to optimal tissue conservation associated with a high cure rate.…”

“…The use of melanocyte-specific immunostains may be associated with decreased recurrence rates with MMS. A recent study of 200 cases of LM/LMM treated by MMS with Mel-5 immunostaining showed a recurrence rate of 0.5% after a follow-up period of 38 months 10. However, few Mohs laboratories (\15% in a recent survey) currently utilize immunostains 6.…”

“…A standard 5-mm excision margin will be inadequate in many cases, 6,7 and recurrence rates of LM after standard excision may approach 20%. 8 Mohs micrographic surgery (MMS) has been advocated for margincontrolled excision of LM and LMM, [9][10][11] though this remains controversial given the challenges in assessing melanocyte atypia in frozen sections. 12 Other authors have advocated staged excision (SE) utilizing permanent paraffin sections.…”

Staged excision for lentigo maligna and lentigo maligna melanoma: A retrospective analysis of 117 cases

“…24 The reliability of frozen sections for interpreting melanoma in situ compared with paraffin-embedded sections has been questioned with Zitelli et al 22 reporting 100% sensitivity and 90% specificity whereas others report lower sensitivity and specificity rates of 73% and 68%, respectively. 12 Immunostains with HMB-45, S-100, MART-1, and Mel-5 have been advocated 11,[25][26][27][28] to overcome frozen section difficulties of freeze artifact and distinguishing actinically damaged keratinocytes from melanocytes, but require additional processing time. An alternative approach is to use frozen sections until a negative margin is achieved and then confirm final margins with permanent sections.…”

Mohs surgery for melanoma: rationale, advances and possibilities

“…While MEL-5 has been used for MS for melanoma [58,59], it is not considered the preferred immunostain owing to nonspecific immunostaining of melanosomecontaining cells, such as basal keratinocytes [8]; as a result, it may falsely stain pigmented actinic keratoses, pigmented Bowen's disease and lichen planus-like keratoses. MEL-5 also does not reliably stain amelanotic or desmoplastic melanoma and the dermal component of melanoma [60].…”