Gastric mesenchymal tumor with smooth muscle differentiation and echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) fusion.
Pathol Int
; 71(10): 707-711, 2021 Oct.
Article
em En
| MEDLINE
| ID: mdl-34432920
ABSTRACT
Gastric mesenchymal tumors are relatively rare, and their molecular pathogeneses are poorly understood, except for gastrointestinal stromal tumor, desmoid, and inflammatory myofibroblastic tumors. We report a case of a gastric mesenchymal tumor with prominent smooth muscle cell differentiation and an echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) fusion. On gross section, the tumor was 26 mm at the largest diameter, well-circumscribed, and located in the submucosal and muscular layers of the stomach wall. Histologically, the tumor comprised intersecting fascicles of spindle cells, non-atypical nuclei, and highly eosinophilic cytoplasm. Myxoid changes were observed focally, but inflammatory infiltrates were only evident in limited areas. Immunochemical staining revealed that the tumor was positive for α-smooth muscle actin and desmin. Diffuse positive staining for h-caldesmon was observed throughout the tumor, which suggested smooth muscle cell differentiation. Intracytoplasmic staining for ALK protein was also observed, and fluorescence in situ hybridization using ALK break-apart probes showed split chromosomal signals. RNA-sequencing analysis identified EML4-ALK fusion transcripts. We concluded that the tumor was a gastric mesenchymal tumor with smooth muscle differentiation based on its distinct differential smooth muscle properties, such as highly eosinophilic cytoplasm and diffuse expression of h-caldesmon. Furthermore, activated ALK may underly the tumor's pathogenesis.
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Base de dados:
MEDLINE
Assunto principal:
Neoplasias Gástricas
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Biomarcadores Tumorais
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Proteínas de Fusão Oncogênica
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Leiomioma
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Músculo Liso
Tipo de estudo:
Prognostic_studies
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Risk_factors_studies
Limite:
Aged
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Female
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Humans
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article