Dermal melanocytic tumor with CRTC1-TRIM11 fusion: Report of two additional cases with review of the literature of an emerging entity.

ABSTRACT

"Cutaneous melanocytic tumor with CRTC1-TRIM11 fusion" (CMTCT) is a newly described, potentially novel entity that typically presents as a dermal nodule on the head and neck, extremities, and trunk of adults. Histopathologically, it is reported as a nodular or multinodular tumor composed of epithelioid and spindle cells that are variably immunoreactive for S100-protein, SOX10, and MITF along with more specific melanocytic markers such as MelanA and HMB45. With only 11 cases reported in the English literature so far, the neoplasm appears to behave in a relatively indolent fashion. Nevertheless, in one case, local recurrence and synchronous distant metastasis were evident after 13 years. Additional cases with longer follow-up are essential to determine the neoplasm's biologic behavior with more accuracy. Herein, two cases of CMTCT, one arising on the lower back of a 65-year-old female and the other on the arm of a 33-year-old female in addition to a comprehensive literature review are reported.