CRTC1‐TRIM11 fusion defined melanocytic tumors: A series of four cases

Abstract

A cutaneous melanocytic tumor with morphologic overlap with clear cell sarcoma, but defined by CRTC1-TRIM11 gene fusion, was recently described in a series of five adult patients. Here, we expand the clinicopathologic features of this entity by four additional cases which include pediatric presentation, exophytic growth, and propensity to occur on the head. Patients (2F; 2M) had a median age of 41 years (range 11-59). Sites of involvement included leg, ear, and face. Tumors were circumscribed, unencapsulated, mostly limited to the dermis, and varied from 5 to 35 mm. One case was exophytic. Lesional cells were arranged in nests and fascicles, and were monomorphic and fusiform with moderate pale to clear cytoplasm, occasional nuclear pseudo-inclusions, and small to prominent nucleoli. Mitotic rate was variable (rare to 12/10 HPF, median 3/10 HPF). The pediatric case showed increased nuclear pleomorphism, tumor necrosis, and mitotic figures. All cases showed strong, diffuse nuclear staining for SOX10, but were negative or focal for S100 protein, HMB45 and Melan-A expression. Cases were positive by FISH technique and/or RNA sequencing for a TRIM11 rearrangement/fusion, and negative for EWSR1 rearrangement. This series is presented to aid in further characterization of this novel melanocytic tumor. K E Y W O R D Sclear cell sarcoma, CRTC1-TRIM11, melanocytoma, melanoma, translocation

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

“…“Cutaneous melanocytic tumor with CRTC1‐TRIM11 fusion (CMTCT)” is a recently described neoplasm with melanocytic differentiation that presents as a superficial nodule on varying anatomic sites. Thirteen cases 1‐4 (including ours) have been described so far, eight on the extremities, three on the head and neck, and two on the lower back. The lesions' median diameter was 10 mm (range 4–51 mm), whereas the patients' median age was 33 years (range 11‐82), including one 11‐year‐old child 3 .…”

“…Thirteen cases 1‐4 (including ours) have been described so far, eight on the extremities, three on the head and neck, and two on the lower back. The lesions' median diameter was 10 mm (range 4–51 mm), whereas the patients' median age was 33 years (range 11‐82), including one 11‐year‐old child 3 . Eight of 13 cases reported occurred in women.…”

“…In 2018, Cellier et al 1 reported a potentially new entity with a recurrent genetic signature that they termed “cutaneous melanocytoma with CRTC1‐TRIM11 fusion (CMCT).” It was described as a dermal proliferation composed of atypical epithelioid and spindle cells with a melanocytic immunophenotype resembling melanoma or CCS. Since then, six more cases harboring the same CRTC1‐TRIM11 fusion have been added to the literature 2‐4 and new nomenclature has been advocated. Bontoux et al, 4 who described a case of a CRTC1‐TRIM11 fused neoplasm that recurred and metastasized after 13 years, suggested that this entity represents a more aggressive cutaneous variant of CCS harboring a novel gene fusion other than the EWSR1‐ATF1 5,6 .…”

“…Bontoux et al, 4 who described a case of a CRTC1‐TRIM11 fused neoplasm that recurred and metastasized after 13 years, suggested that this entity represents a more aggressive cutaneous variant of CCS harboring a novel gene fusion other than the EWSR1‐ATF1 5,6 . Subsequently, Ko et al 3 proposed the term “cutaneous melanocytic tumor with CRTC1‐TRIM11 fusion” to reflect the new data on the neoplasm's biologic behavior. Herein, we present two additional cases of this emerging, potentially novel entity in an effort to enrich the literature and familiarize general pathologists.…”

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

“…Reactivity for Melan-A and HMB45 is usually negative or focal. [5] Complete excision of the tumour is the rule of treatment.…”