http://www.histopathology-india.MelanocyticTumours.htm

It is the most common type of malignant melanoma in Asians, African and North American Blacks, but is relatively infrequent in Caucasians.

It occurs predominantly in the sixth, seventh, and eighth decades of life, with a peak incidence in the seventh decade for males and in the sixth decade for females.

These lesions are usually located on palmar, plantar and subungual skin. 

Macroscopically, the lesion presents as  pigmented and ulcerated plaques or nodules. 

Histologically, the tumour has a radial growth phase and is characterized by lentiginous and some nesting proliferation of atypical melanocytes.  Focally, pagetoid spread is present, however this is not as prominent as in superficial spreading melanoma. The melanocytes may be surrounded by a halo giving a lacunar appearance. Some of the melanocytes may have dendritic processes. The invasive dermal component may be composed of spindle or epithelioid  cells or nevus like cells.  

Diagnosis of ALM during the radial growth phase is often difficult, and it may not be recognized initially, but treatment in this phase offers an excellent prognosis.

There is a high incidence of regressive changes and desmoplasia in ALM.

These changes, together with the anatomic peculiarities of nail beds, palms, and soles as compared with other skin areas, make it difficult to determine the Clark's level and to measure the depth of invasion.

Treatment:

i) Melanomas less than 1.00 mm deep and those in the radial growth phase with minimal invasion require only wide local excision.

ii) Wide local excision with lymph node dissection is recommended for subungual melanomas measuring more than 1.00 mm and for lesions showing severe regression. 

iii) Amputation of digits and lymph node dissection are recommended for subungual melanomas, if the melanomas exhibit the vertical growth phase.

iv)If there is only radial growth without regressive changes, wide local excision is adequate.

 IMAGE LINK: Image1 ;  Image2  ; Image3 (Dr.Weems)   

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Epidermal Naevus

Prurigo Nodularis

Acanthomas

Inflammatory diseases of the Eyelid

Tumour and tumour-like lesions of the Eyelid

Adnexal Tumours of the eyelid

Epidermal tumours of the Eyelid

Mesenchymal Tumours of the Eyelid

Melanocytic tumours of the Eyelid