Cutaneous melanocytic tumour with CRTC1::TRIM11 fusion in a case with recurrent local lymph node and distant pulmonary metastases at early stage: aggressive rather than indolent?

MED15::ATF1-Rearranged Tumor: A Novel Cutaneous Tumor With Melanocytic Differentiation

We recently described novel dermal tumors with melanocytic differentiation and morphologic and biological similarities to cutaneous clear cell sarcoma, including CRTC1::TRIM11 cutaneous tumor, and clear cell tumors with melanocytic differentiation and either ACTIN::MITF or MITF::CREM. Here, we describe a series of 3 patients presenting with tumors reminiscent of CRTC1::TRIM11 cutaneous tumor, found to demonstrate a novel MED15::ATF1 fusion. All 3 patients were children (5-16 years old). Primary excision of case 1 showed a circumscribed wedge-shaped silhouette with peripheral intercalation into collagen fibers and scattered lymphoid aggregates. All 3 tumors abutted the epidermis; one showed a junctional component. Tumors were highly cellular and comprised of monomorphic, oval-to-round epithelioid cells arranged in vague nests and short fascicles in variably fibrotic stroma. Mitotic rate was high (hotspot 6-12/mm2), without atypical mitoses. Necrosis was focally present in case 3. All cases showed strong, diffuse nuclear staining for SOX10 and MITF (2/2) but showed variable expression for S100 protein (1/3) and other melanocytic markers-Melan-A (focal in 2/3), HMB45 (focal in 1/3), and Pan-Melanoma (patchy in 1/1). Whole-exome RNA sequencing demonstrated a MED15::ATF1 fusion without any other notable alterations. Cases 1 and 2 were completely excised without recurrence (12 months). Case 3 developed a grossly apparent regional lymph node spread shortly after primary biopsy. The patient was treated with wide excision, radiation, cervical lymph node dissection (4/46 with >75% lymph node replacement), and neoadjuvant and adjuvant nivolumab (alive without disease at cycle 11). This series is presented to aid in future diagnosis of this novel dermal tumor with melanocytic differentiation and emphasize the potential for aggressive biologic behavior, which should be considered in patient management planning.

Cutaneous melanocytic tumor with CRTC1::TRIM11 fusion: a case report

BACKGROUND

Cutaneous Melanocytic Tumor with CRTC1::TRIM11 Fusion (CMTCT) represents a novel and rare entity in the realm of dermatological oncology, characterized by distinct melanocytic differentiation. This particular tumor type has yet to be officially recognized by the World Health Organization (WHO). CMTCT is generally perceived as a tumor with a relatively indolent nature; however, it is not devoid of metastatic potential. Therefore, ensuring complete surgical excision of the tumor, coupled with rigorous long-term follow-up, is paramount for patient management. In this context, we report the case of an 18-year-old female patient who presented with a dull red nodule on her left leg. Initial surgical intervention led to a pathological diagnosis of CMTCT, but it was determined that the tumor had not been fully excised. Consequently, a second surgical procedure was undertaken to achieve complete removal of the tumor. During a follow-up period of six months post-surgery, the patient showed no signs of local recurrence or metastasis, indicating a successful outcome.

CASE PRESENTATION

An 18-year-old female patient noticed a dull red nodule on her left leg three years ago, which exhibited slow growth over time. She underwent a subcutaneous tumor resection. Histological examination under high-power magnification revealed that the neoplasm consisted of epithelioid cells arranged in nests, fascicles, bundles, or sheets. The tumor cells had round or ovoid nuclei with prominent nucleoli and visible mitotic figures. Notably, areas resembling nevus cell clusters were observed. Immunohistochemical analysis confirmed melanocytic differentiation. Next-generation sequencing (NGS) identified a CRTC1::TRIM11 fusion, and fluorescence in situ hybridization (FISH) for CRTC1 confirmed rearrangement. Consequently, a diagnosis of cutaneous melanocytic tumor with CRTC1::TRIM11 fusion was established.

CONCLUSIONS

CMTCT is a rare tumor characterized by melanocytic differentiation. In this case, the tumor predominantly comprised epithelioid cells with localized nevus cell clusters. The expression of melanocyte markers could easily lead to a misdiagnosis as cutaneous melanoma. However, several distinguishing features were noted: the tumor was not connected to the epidermis, exhibited low cellular heterogeneity and proliferation index, and showed minimal cellular atypia. Additionally, tests for EWSR1 rearrangement (FISH) and BRAF V600E mutation (PCR-ARMS) were negative.This case underscores the importance of a comprehensive diagnostic approach when clinical, microscopic, immunohistochemical, and molecular findings do not align. The presence of nevus cell clusters morphology in the tumor cells enhances our understanding of this disease's histological spectrum and aids in avoiding misdiagnosis or missed diagnosis.

What's new in dermatopathology 2023: WHO 5th edition updates

The 5th edition WHO Classification of Skin Tumors (2022) has introduced changes to nomenclature and diagnostics. Important differences are discussed below. Changes in each category of skin tumor have been detailed, with particular emphasis on meaningful advances in our understanding of the molecular pathogenesis of the skin's diverse tumor landscape.

TRIM11 promotes cell proliferation of non-small cell lung cancer through the inhibition of ferroptosis by AMPK

Lung cancer is one of the leading causes of cancer-related deaths worldwide, with non-small cell lung cancer (NSCLC) being the most prevalent type. This study investigates the role of TRIM11 gene in NSCLC and its underlying mechanism. NSCLC patients were recruited from our hospital and showed upregulated TRIM11 mRNA and protein expressions. Patients with high TRIM11 expression had lower survival rates. TRIM11 gene was found to promote cell proliferation and reduce ROS-induced ferroptosis in NSCLC. Additionally, TRIM11 gene induced AMPK expression and its regulation affected TRIM11's effects on cell proliferation and ferroptosis in NSCLC. IP analysis revealed that TRIM11 protein interacted with AMPK protein in NSCLC. These data confirmed that TRIM11 promotes cell proliferation and reduces ROS-induced ferroptosis in NSCLC through AMPK. Hence, TRIM11 is a potential target for the treatment of NSCLC and other cancers.

Gene fusions in superficial mesenchymal neoplasms: Emerging entities and useful diagnostic adjuncts

Cutaneous mesenchymal neoplasms are diagnostically challenging because of their overlapping morphology, and, often, the limited tissue in skin biopsy specimens. Molecular and cytogenetic techniques have identified characteristic gene fusions in many of these tumor types, findings that have expanded our understanding of disease pathogenesis and motivated development of useful ancillary diagnostic tools. Here, we provide an update of new findings in tumor types that can occur in the skin and superficial subcutis, including dermatofibrosarcoma protuberans, benign fibrous histiocytoma, epithelioid fibrous histiocytoma, angiomatoid fibrous histiocytoma, glomus tumor, myopericytoma/myofibroma, non-neural granular cell tumor, CIC-rearranged sarcoma, hybrid schwannoma/perineurioma, and clear cell sarcoma. We also discuss recently described and emerging tumor types that can occur in superficial locations and that harbor gene fusions, including nested glomoid neoplasm with GLI1 alterations, clear cell tumor with melanocytic differentiation and ACTIN::MITF translocation, melanocytic tumor with CRTC1::TRIM11 fusion, EWSR1::SMAD3-rearranged fibroblastic tumor, PLAG1-rearranged fibroblastic tumor, and superficial ALK-rearranged myxoid spindle cell neoplasm. When possible, we discuss how fusion events mediate the pathogenesis of these tumor types, and we also discuss the related diagnostic and therapeutic implications of these events.

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

A cutaneous melanocytic tumor with CRTC1::TRIM11 fusion (CMTCT) was recently described as a novel superficial tumor with melanocytic differentiation and harboring a unique in-frame translocation, CRTC1::TRIM11. This emerging entity can occur at any age and is known to be a low-grade malignant neoplasm with limited follow-up data. There are no available guidelines for the management and treatment of this tumor. This neoplasm has been found in the extremities, head and neck, and trunk. Here, we present the first case occurring on acral digital skin. This case contributes to the growing knowledge surrounding this newly described entity.