Whose Nose Needs Mohs?

Abstract:  77 yo woman with 5 mo history of pigmented macule on nose

HPI:  77 yo woman in fair general health with 5 mo history of evolving lesion on bridge of nose.

O/E: 1.5 x1.0 macule with slight play of color bridge nose.

Clinical photos: Arrows show original biopsy sites.

Biopsies:
1) 2 x 3 mm punch bx taken from areas indicated by arrows.  "Mild to moderate atypical melanaocytic hyperplasia with focal pagetoid spread.
2) Incisional biopsy of most (not all) of residual lesion. "Lentiginous melanocytic hyperplasia best interpreted as 'melanoma in situ.' In the appropriate clinical setting complete reexcision is recommended for further evaluation and management."

(Biopsies were signed out by two different dermatopathologists at the same facility.)

Photomicrographs courtesy of Dr. Deon Wolpowitz, Boston University, Department of Skin Pathology.

Mart 1 Positive 

Diagnosis:  Atypical Melanocytic Hyperplasia vs. Melanoma in situ

Discussion: Clearly, a more complete excision would be problematic.  This lesion would appear to have minimal potential to metastasize and the plan here would be either wait and watch or imiquimod.  What would your approach be? 
What is highlighted here is the subtle change of diagnosis from atypical melanocytic hyperplasia to M.I.S.  Semantics certainly makes a difference.

Questions: Would you refer to a Mohs surgeon or  treat with imiquimod?  What is the risk for invasion in such a lesion?

About MART 1 Stain: MART-1 has nothing to do with prognosis or treatment.  It is basically a staining tool to identify melanoma cells in a tissue sample.  Having MART-1 positive means melanocytes showed up on the sample and the pathology can confirm melanoma.  MART-1 is specific to melanoma so when cells stain positive, there are melanocytes there.  It also shows normal melanocytes, but if it stains positive in a tissue sample that shouldn't contain melanocytes (tumors), then you have a key to diagnosis

References:

1.  An Bras Dermatol. 2011 Jul-Aug;86(4):792-4.

Lentigo maligna treated with topical imiquimod: dermatoscopy usefulness in clinical monitoring.

[Article in English, Portuguese]  Free Open Access

Costa MC, Abraham LS, Barcaui C.

Instituto de Dermatologia Prof. Rubem David Azulay, Santa Casa da Misericórdia do Rio de Janeiro, Brasil.

Abstract: Dermoscopy has its usefulness well established in the diagnostic evaluation of melanocytic lesions. Recently, however, it has also shown to be an important tool in monitoring therapeutic response to various dermatoses. We report the case of an elderly patient diagnosed with lentigo maligna of difficult surgical management, which we have chosen to treat with topical imiquimod. The dermoscopic monitoring of this alternative therapy has shown to be of great usefulness.

2.  Case Rep Dermatol. 2009 Oct 31;1(1):78-81.

Topical Imiquimod Treatment of Lentigo Maligna.

Ventura F, Rocha J, Fernandes JC, Pardal F, Brito C.

Source: Department of Dermatology and Venereology, Hospital de São Marcos, Braga, Portugal. Free Open Access

Abstract: Lentigo maligna (LM) is the in situ phase of lentigo maligna melanoma, which may progress to invasive melanoma if left untreated. It mainly occurs on sun-exposed areas of elderly patients. The lesions can be large and conventional surgery can be difficult, particularly on the face. Recent reports indicate that topical imiquimod 5% cream is effective in the treatment of LM. It may be an alternative when surgery or other classical treatments are not possible in elderly patients. We describe an 80-year-old Caucasian woman with a 10-year history of a histologically verified extensive LM of the face. She was treated with imiquimod 5% cream once daily. After four months it showed complete clinical response. One year after the treatment the patient was still free from recurrence.as shown to be of great usefulness.

3. 

--> Clin Med Oncol. 2008; 2: 551–554.

Observational Study of Topical Imiquimod Immunotherapy in the Treatment of Difficult Lentigo Maligna

E.E. Craythorne and C.M. Lawrence  Free Open Access.