Version July 2025
| Genetic alterations | Morphologic features | Distinctive phenotypes |
| ALK fusions | Plexiform and fascicular architecture, spindle and epithelioid cells, amelanotic, angiomatous, myxoid |
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| BRAF fusions | Dome- or plaque-type configuration, predominately dermal, desmoplastic, epithelioid and nevoid cells |
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| HRAS mutations | Desmoplastic, epithelioid and spindle cells, low mitotic rate |
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| MAP3K fusions and truncations | Ulceration often, epithelioid cells, multinucleate giant cells, absence of maturation, moderate to high-grade atypia |
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| MET fusions | No distinctive features | |
| NTRK1 fusions | Filigree-like rete ridges, lobulated melanocytic nests, fascicular, rosette structures. Extreme maturation, more spindle cells than epithelioid cells, nevoid cells. |
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| NTRK3 fusions (mainly MYO5A::NTRK3) | Pigmented spindle cells, slender spindle cells, fascicular, plexiform, neuroid, Verocay-like structures, rosettes |
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| RET fusions | Plaque-type, discohesive nesting, small to intermediate-sized epithelioid and spindle cells |
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| ROS1 fusions | Prominent junctional nests, "floating nests," transepidermal elimination, spindle and epithelioid cells, often, maturation, lack of high-grade atypia |
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