Some reported atypical features observed in Spitz “naevi”
| Clinical size greater than 1.0 mm12,13 |
| Incomplete maturation12–16 |
| Deep dermal mitoses13,14,15,16 |
| Atypical mitoses12,13 |
| Nuclear pleomorphism/hyperchromatism12,14 |
| Focal sheet-like growth13,14 |
| Ulceration (in absence of trauma)13 |
| Abundant plasma cells in lesional inflammation15,16 |
| Thickness (8 mm)13,15 |
| Extension into subcutaneous tissue13,16 |
| Pushing base16 |
| Focal necrotic melanocytes16 |
| Deep pigmentation10,16 |
| Destruction of collagen12 |
| Prominent pagetoid spread without epidermal hyperkeratosis12 |
| Lymphatic spread/nodal involvement14,16,17 |