Melanoma-in-Situ

This 79 yo man has a pigmented lesion that has been slowly enlarging on his right arm for around a decade.

O/E:  There is a 3 cm pigmented patch with a subtle play of color on the dorsal surface of his right arm.  The border is slightly irregular.  Dermatoscopy confirms the play of color showing variations in brown patches containing black dots admixed with reticular hypopigmented areas.

Pathology:  A 4 mm punch biopsy was taken.  This showed atypical melanocytic hyperplasia arranged in nests and single cells at and above the dermal epidermal junction and extending along the adnexae.  (Photomicrographs courtesy of Dr. Lynne Goldberg, Department of Dermatology, Boston University School of Medicine)

Diagnosis: consistent with melanoma in situ (MIS).

Questions:

1) Is it possible to suspect MIS on dermatoscopy over melanoma in this case?

2) Although excision is the preferable treatment, would Mohs, or even imiquimod be acceptable alternatives?

3) How likely is this lesion to become invasive?  It's been present now for 10 years or greater.
4) Under what circumstances would "active surveillance" be appropriate.

References:

1. M A Pizzichetta  et.al.

Dermoscopic Criteria for Melanoma in Situ Are Similar to Those for Early Invasive Melanoma. Cancer, 91 (5), 992-7 2001

2. Kevin Phan, Asad Loya. Mohs Micrographic Surgery Versus Wide Local Excision for Melanoma in Situ: Analysis of a Nationwide Database. Int. J. Dermatol 58 (6), 697-702, Jun 2019

Conclusion: Adjusted analyses demonstrated no differences in overall survival or cancer-specific survival between MIS patients treated with MMS compared with WLE.

3. Long-Term Outcomes of Melanoma In Situ Treated With Topical 5% Imiquimod Cream: A Retrospective Review

Andrew J Park et. al. Long-Term Outcomes of Melanoma In Situ Treated With Topical 5% Imiquimod Cream: A Retrospective Review. Dermatol Surg: 43 (8), 1017-1022 Aug 2017

Results: Of 12 patients with histologically confirmed MIS treated with topical 5% imiquimod cream, there were 2 recurrences (17%) during a median follow-up time of 5.5 years.

Conclusion: Although surgery is still considered the gold standard for the treatment of MIS, imiquimod may represent a potentially effective noninvasive treatment option for patient who are not surgical candidates.

4.  D Tio, et. al. Variation in the Diagnosis and Clinical Management of Lentigo Maligna Across Europe: A Survey Study Among European Association of Dermatologists and Venereologists Members. J Euro Acad Dermatol, 32 (9), 1476-1484 2018