SPINDLE CELL NEVUS (SPITZ)
This is another example of a spindle cell or spindle and epithelioid cell
melanocytoma of Spitz (more commonly called spindle
cell nevus). The nesting pattern within the epidermis is dominant in
this example, but cells and clusters of cells are found in a pagetoid distribution.
There are keratinocyte hypertrophy and epidermal hyperplasia
similar to that which can be seen in the radial growth component of a superficial
spreading melanoma. The mitosis that is illustrated is in an intraepidermal
cluster, but mitoses can be seen in the dermal component of spindle cell
nevi. Eosinophilic blobs (Kamino bodies) were once thought to be restricted
to spindle cell nevi, but they have been found in a few melanomas.
If one encounters a lesion having the features of a spindle cell nevus,
the usual diagnostic algorithm that might lead to a diagnosis of malignant
melanoma is interrupted. False positive and false negative diagnoses occur
with troublesome frequency in this area of dermatopathology.
Composite low power view (above)
 |
High power showing cells in a pagetoid distribution.
Keratinocyte hypertrophy and epidermal hyperplasia are also present. |
 |
High power showing a mitotic figure (mf). |
 |
High power showing Kamino bodies (Kb). |
Click on your browser's 'Back' button to go to the previous page.
