Spitz Tumors of the Skin.

Spitz tumors are melanocytic neoplasms hallmarked by large cell size, lack of high-grade atypia, and a regular architecture. Most are nonpigmented or poorly pigmented. Malignant potential ranges from absent (Spitz nevus), to fully present (spitzoid melanoma), with a further, ill-defined group of Spitz tumors with limited metastatic potential. Microscopic evaluation may prove inconclusive in some instances, resulting in a verdict of Spitz tumor of uncertain malignant potential (STUMP). STUMP is, therefore, not an entity, and should not be equated with Spitz tumors with limited metastatic potential. Novel diagnostic techniques are yielding promising results, and further evaluation is ongoing.