Malignant neuroectodermal tumor with melanocytic and rhabdomyoblastic differentiation

• Main Authors: Brian P. Rubin, Munir R. Tanas
• Format: Article
• Language: English
• Published: SAGE Publishing 2009-12-01
• Series: Rare Tumors
• Subjects: Malignant peripheral nerve sheath tumor (MPNST); malignant melanoma; melanocytic differentiation; rhabdomyoblastic differentiation; malignant neuroectodermal tumor
• Online Access: http://www.pagepress.org/journals/index.php/rt/article/view/1100

Malignant melanoma can metastasize widely and vary significantly in its histological appearance; it rarely presents as a deep-seated mass without an obvious primary site elsewhere. Malignant peripheral nerve sheath tumor (MPNST) is a high-grade sarcoma characterized by conventional and epithelioid subtypes. MPNST can demonstrate heterologous differentiation, usually in the form of osteosarcomatous, chondrosarcomatous, or rhabdo-myosarcomatous differentiation. MPNST does not harbor true melanocytic differentiation, although epithelioid MPNST typically is diffusely S-100 protein positive and superficially can resemble malignant melanoma. An unusual intra-abdominal mass was recently encountered with features of both melanoma and conventional or epithelioid MPNST containing a fascicular spindle cell component, an epithelioid component with melanocytic differentiation, as well as a rhabdomyosarcomatous component. The terminology “malignant neuroectodermal tumor with melanocytic and rhabdomyoblastic differentiation” is proposed to describe this neoplasm, reflecting the unusual concomittant lines of differentiation as well as offering a possible rationale for nosologically challenging aspects of this neoplasm.