1
|
Tseng C, Wiedemeyer K, Mehta A, Rojas-Garcia P, Temple-Oberle C, Orlando A, Miller K, Gharpuray-Pandit D, Brenn T. The clinico-pathological spectrum of plaque-type blue naevi and their potential for malignant transformation. Histopathology 2024; 84:1047-1055. [PMID: 38305122 DOI: 10.1111/his.15152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 01/13/2024] [Accepted: 01/16/2024] [Indexed: 02/03/2024]
Abstract
AIMS Plaque-type blue naevi are rare melanocytic tumours presenting as large, pigmented plaques at birth or during childhood. There is a risk for malignant transformation, but no larger comprehensive studies exist and the diagnosis is challenging, especially on limited biopsy material. The aim is to describe the clinicopathological features and behaviour of the disease more comprehensively. METHODS AND RESULTS We retrieved eight plaque-type blue naevi, presenting as large, pigmented plaques (median = 7 cm; range = 3-26) most frequently affecting the scalp (four) followed by the cheek, arm, abdominal wall and gluteal cleft (one each), with a slight female predilection. Median age at time of biopsy was 39.5 years (range = 15-90), but three tumours had been present at birth and one since childhood. Histopathologically, the tumours were poorly circumscribed and composed of cellular fascicles of uniform spindle cells in a background of variably prominent pigmented dendritic cells affecting dermis and subcutaneous tissues. The majority had mutations in GNAQ. One tumour showed malignant transformation, characterised by an expansile nodule of pleomorphic epithelioid melanocytes with rhabdoid morphology, high mitotic activity and areas of necrosis. This patient developed metastatic melanoma to lymph nodes. All patients are alive with a median follow-up of 60 months. CONCLUSION Plaque-type blue naevi are diagnostically challenging tumours with risk for malignant transformation. Awareness and familiarity with the salient clinicopathological features are necessary for reliable diagnosis, and long-term clinical follow-up is required to monitor for malignant transformation.
Collapse
Affiliation(s)
- Calvin Tseng
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Katharina Wiedemeyer
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Arjun Mehta
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, Alberta, Canada
| | | | - Claire Temple-Oberle
- Department of Surgery and Oncology, University of Calgary, Calgary, Alberta, Canada
| | - Antonio Orlando
- Department of Plastic and Reconstructive Surgery, Southmead Hospital Bristol, Bristol, UK
| | - Keith Miller
- Department of Cellular Pathology, Southmead Hospital, North Bristol NHS Trust, Bristol, UK
| | | | - Thomas Brenn
- Department of Pathology and Clinical Laboratories, Michigan Medicine, University of Michiga, Ann Arbor, MI, USA
| |
Collapse
|
2
|
Kervarrec T, Lo Bello G, Pissaloux D, Tirode F, Poulalhon N, Samimi M, Houlier A, de la Fouchardière A. GRM1 Gene Fusions as an Alternative Molecular Driver in Blue Nevi and Related Melanomas. Mod Pathol 2023; 36:100264. [PMID: 37391170 DOI: 10.1016/j.modpat.2023.100264] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/14/2023] [Accepted: 06/21/2023] [Indexed: 07/02/2023]
Abstract
Activating mutations in GNAQ, GNA11, CYSLTR2, and PLCB4 genes are regarded as the main oncogenic drivers of blue nevi (BN) and blue malignant melanocytic tumors. Here we report 4 cases of blue melanocytic neoplasms devoid of these mutations but harboring GRM1 gene fusions. In this short series, there was no gender predominance (sex ratio, 1). The mean age at diagnosis was 40 years (range, 12-72). Tumors were located on the face (n = 2), forearm (n = 1), and dorsum of the foot (n = 1). Clinically, a plaque-like pre-existing BN was found in 2 cases, including a deep location; another case presented as an Ota nevus. Two cases were diagnosed as melanoma ex-BN, one as an atypical BN, and one as a plaque-like BN. Microscopic examination revealed a dermal proliferation of dendritic melanocytes in a sclerotic stroma. A dermal cellular nodule with atypia and mitotic activity was observed in 3 cases. Genetic investigation by whole exome RNA sequencing revealed MYO10::GRM1 (n = 2) and ZEB2::GRM1 (n = 1) fusions. A GRM1 rearrangement was identified by fluorescence in situ hybridization in the remaining case. SF3B1 comutations were present in the 2 melanomas, and both had a MYO10::GRM1 fusion. Array comparative genomic hybridization was feasible for 3 cases and displayed multiple copy number alterations in the 2 melanomas and limited copy number alterations in the atypical BN, all genomic profiles compatible with those of classical blue lesions. GRM1 was overexpressed in all cases compared with a control group of blue lesions with other typical mutations. Both melanomas rapidly developed visceral metastases following diagnosis, with a fatal outcome in one case and tumor progression under palliative care in the other. These data suggest that GRM1 gene fusions could represent an additional rare oncogenic driver in the setting of BN, mutually exclusive of classical canonical mutations, especially in plaque-type or Ota subtypes.
Collapse
Affiliation(s)
- Thibault Kervarrec
- Department of Pathology, Centre Hospitalier Universitaire de Tours, Tours, France; Biologie des infections à Polyomavirus, INRA UMR 1282 ISP, Université de Tours, Tours, France
| | | | - Daniel Pissaloux
- Department of Biopathology, Centre Léon Bérard, Lyon, France; INSERM U 1052 CNRS 5286, Centre Léon Bérard, Cancer Research Center of Lyon, Equipe Labellisée Ligue contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Franck Tirode
- INSERM U 1052 CNRS 5286, Centre Léon Bérard, Cancer Research Center of Lyon, Equipe Labellisée Ligue contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Nicolas Poulalhon
- Department of Dermatology, Hospices Civils de Lyon, Hôpital Lyon Sud, Pierre-Bénite, France
| | - Mahtab Samimi
- Department of Dermatology, Tours University Hospital, France
| | - Aurélie Houlier
- Department of Biopathology, Centre Léon Bérard, Lyon, France
| | - Arnaud de la Fouchardière
- Division of Pathology, St. Anna Hospital, ASST Lariana, Como, Italy; Department of Biopathology, Centre Léon Bérard, Lyon, France.
| |
Collapse
|