Friday, January 17, 2020


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).

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.

1. M A Pizzichetta
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


  1. From John Karnes, Augusta, Maine: hat’s tough case which highlights the challenges of advising an older patient with of a slow growing tumor. I’m not expert at teasing apart invasive disease from MIS based on dermoscopy alone but it could be suggested by the thinness clinically, lack of blue white veil, lack of atypical streaks/globules which would all suggest dermal components of disease.

    Mohs or slow Mohs is possible with a willing and practiced person and the data is promising but incomplete. This was great for a patient of mine who kept having positive margins with plastics excisions on a forehead. We have someone in our office in Maine now offering this. I like it best for MIS without obvious borders and for highly cosmetically sensitive areas. I’ve used imiquimod with success and failure—leading to a prolonged course of treatment.

    I think the cognitive burden of disease can be hard to place a value on but comes into the equation. These are slow moving tumors with 15 year survival numbers, until suddenly, for a few unfortunates, they invade. An excision has a 99+% of complete cure—which if easy enough to accomplish I think improves sleep for patients and doctors alike. If that tumor covered the nose, or the eyelid it would be a tougher risk benefit balance to strike. However, I think on the arm, I’d recommend surgery. In a week or two it would all be in the rear view.

  2. From Dato Ong Cheng Leng, Malaysia: Dad

    8:12 AM (4 hours ago)

    to me
    Dear David,

    I’ve just finished the eating part of the Chinese New Year Eve Reunion with my big family, the rest of the Chinese New Year is from this point to the fifteenth day of Chinese New Year. I’m closing my clinic for till the seventh day. Nevertheless, I’m most glad to answer your questions in the midst of my family and the festivities.

    Please include the rest of history taking:-
    1. Any paraesthesia arising from lesion?
    2. Rapid growth phase recently though it has been there for 10 years.
    3. Haemorrhage?
    4. Any family history of melanoma or at least multiple bizarre nevi? Dr Bernie Ackerman from New York told us he personally consider these in situ lesions as frank melanoma.
    5. Regional lymphadenopathy ?

    Clinically lesion is much bigger than the comfort of 1 cm diameter; no obvious variegation of colours but as you’ve subtly put it, a subtle display colour or pigmentation rather, to me that’s alarming.
    The adnexa though still embryological part of epidermis, but the actual depth is absolute.

    If history retaken shows more unfavourable factors, the lesion is to be taken out with at least two cm margin, since there is no important structures near by on his arm. I don’t even waste time looking for a Moh surgeon let alone bargaining over fees. Any surgeon who goes to great depth will do, since it can be considered in situ. Our good surgeon will remove it completely and cure it for good. Any future follow up can be a debate for oncologists though. I will not play around with imiquimod, not knowing for certainty that the melanoma has been dealt with effectively. Who will be legally or even worse, morally responsible?

  3. From Khalifa Sharquie, Baghdad, Iraq:
    his is very interesting case as the first my diagnosis will be pigmented solar keratosis which is more common than malignant melanoma in situ.The clinical differentiation between them both clinically and histopathological could be impossible.Also dermoscopy could be confusing.Hence in this case we need specific tests for melanocytes .
    As a therapy for both conditions,I suggest curretage and cautery will be curative which is very simple procedure .
    Please see:
    "Pigmented Actinic Keratosis: Case Report and Review of an Uncommon Actinic Keratosis Variant that can Mimic Melanoma"


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