Dark skin focalities

Author: Mikael Häggström

Dark skin focalities (in this case, from top left and clockwise: Spitz nevus, seborrheic keratosis, elevated melanocytic nevus and melanoma)

Skin with one or more areas that are darker than the surroundings.

Fixation

• Generally: Buffered 4% formaldehyde.

Microscopic evaluation

File:Pie chart of incidence and malignancy of pigmented skin lesions.png

Various diagnoses of pigmented skin lesions, by relative incidence upon biopsy, and malignancy potential.

Evaluation is largely based on the relative incidence and malignancy of various differential diagnoses (see pie chart). Main approaches are:

• Direct pattern recognition
• Systematic

Pattern recognition

• Melanocytic nevus
  Melanocytic nevus
• Melanoma
  Melanoma
• Blue nevus
  Blue nevus
• Seborrheic keratosis
  Seborrheic keratosis
• Basal cell carcinoma
  Basal cell carcinoma

Systematic

By their relative incidences, one practical approach is:

• Is it a dysplastic (melanocytic) nevus? If not:
• Is it a Melanoma? If not:
• Compare to patterns of various other possibilities.

Main page

• Main page of Patholines