Smooth Muscle Tumors

2022-03-01   Paola Dal Cin 

1.Brigham and Women's Hospital , Harvard Medical School, Boston , MA (USA)

Classification

Definition

They may occur in any body parts where smooth muscles are present, and are  considered an essentially dichotomous group composed of benign leiomyomas and malignant leiomyosarcomas.1,2

Smooth mucle tumoursGenetic Event(s)
Leiomyoma Similar aberations in uterine leiomyoma e.g. 12q14.3 HMGA2 , 8q12 PLAG1, del(7q) rearrangement,expressing MED12 but none of them had MED12 exon 2 mutation. 3
MED12 exon 2 mutations .4,5
Single fusion reports in deep seated lesions: t(10;17)(q22;q21) associated to KAT6B::KANSL1; 6 t(9;22)(q33;q12) associated to EWSR1::PBX3. 7
EBV-associated smooth muscle tumours (EBV-SMT)Rare Epstein-Barr virus (EBV)+ smooth muscle tumours arising in three distinct clinical settings related to immunosuppression: (i) HIV infection, 8 (ii) solid organ transplant recipients,9 and (iii) congenital immunodeficiency disorders. 10,11 In situ hybridization for Epstein-Barr encoding region (EBER) , the most reliable confirmatory test in the absence of PCR-based methodologies. 9
Inflammatory leiomyosarcoma (ILMS)Near-haploid karyotype with/without whole genome doubling.12,13 Similarr morphologic and genetic features have been reported in "histiocyte-rich rhabdomyoblastic tumor".14
LOH of most chromosomes, except for chrs 5 and 22, and often for chrs. 18, 20 and 22.15
NF1 mutations in a subset of cases. 13
Leiomyosarcoma (LMS)Chromosomal instability: complex karyotype, whole-genome duplication and chromosomal losses affecting tumor suppressor genes such as TP53, RB1, and PTEN.16,17 Near-universal biallelic TP53 and RB1 inactivation.18 Amplification of myocardin MYOCD gene in a subset of cases.19
Alternative telomere lengthening (78%) and recurrent alterations in telomere maintenance genes such as ATRX,RBL2, and SP100.18
Genomic signatures of homologous recombination deficiency.18,20
Genetic predisposition: Li-Fraumeni syndrome OMIM:151623 and hereditary retinoblastoma OMIM:180200

Bibliography

Reference NumberPubmed IDLast YearTitleAuthors

Citation

Paola Dal Cin

Smooth Muscle Tumors

Atlas Genet Cytogenet Oncol Haematol. 2022-03-01

Online version: http://atlasgeneticsoncology.org/solid-tumor/208939/js/lib/jquery-3.5.1.min.js