Clear Cell Tumor with Melanocytic Differentiation and ACTIN-MITF Translocation

**Semantic type:** Neoplastic Process

**Definition:** A MITF pathway-activated melanocytic tumor characterized by a cytogenetic translocation between ACTIN and MITF genes that results in ACTIN-MITF gene fusion. It presents as a single non-pigmented cutaneous nodule in the distal extremities or trunk. It is composed of large cells with clear cytoplasm that exhibit melanocytic differentiation and proliferate in the dermis without an intraepidermal component. Extension in the subcutaneous tissue is frequently seen. Atypical nuclear features may be present. It has an indolent clinical course.

**Synonyms:** - CCTMAM - Clear Cell Neoplasm with Melanocytic Differentiation and ACTIN-MITF Translocation - Clear Cell Neoplasm with Melanocytic Differentiation and ACTIN::MITF Translocation - Clear Cell Tumor with Melanocytic Differentiation and ACTIN::MITF Translocation - Skin Clear Cell Tumor with Melanocytic Differentiation and ACTIN-MITF Translocation