A new case of cutaneous melanocytoma harbouring the CRTC1‐TRIM11 fusion: case report

Abstract

Background: The diagnosis of dermal primary and metastatic melanocytic tumors is often problematic. Recently, a new entity has been proposed, cutaneous melanocytoma with CRTC1‐TRIM11 fusion (CMCT). Case presentation: We report the 11th case of cutaneous melanocytoma harbouring the CRTC1-TRIM11 fusion. The patient is a 35‐year‐old female patient, with no particular history, who presented in the dermatology department for a 1.5cm nodular lesion on the dorsal aspect of the left foot. The lesion evolved for more than one year. She underwent tumour resection for clinical suspicion of malignant melanoma. Pathological examination of the resected specimen after H&E stain revealed a dermal symmetrical proliferation made of spindle cells showing a melanocytic differentiation proved by expression of Melan A, S100 protein and SOX10. FISH study helped exclude a clear cell sarcoma. RNA sequencing showed the CRTC1-TRIM11 fusion.Conclusions: Since only 11 cases have been documented, and because of the overlap with the clear cell sarcoma, the characterization of CMCT is still not fully satisfactory.

A Case of Digital Cutaneous Melanocytic Tumor With CRTC1::TRIM11 Fusion

“…Cutaneous melanocytic tumor with CRTC1::TRIM11 fusion (CMTCT) was first reported in 2018 [1]. To date, 47 cases have been reported in the literature, including the largest series of 41 cases comprising 32 new cases and nine previously reported cases published in November 2022 [1][2][3][4][5][6][7][8]. This entity can be seen in adults of all ages, and there have also been four cases described in children [2,3].…”

“…CMTCT is believed to be a low-grade malignant neoplasm. Most patients undergoing complete excision had a good prognosis without recurrence or metastasis [1][2][3][4][5][6][7]. Three out of 47 patients had local recurrence and metastasis after the initial resection [3,4,8].…”