PMID- 37962685 OWN - NLM STAT- MEDLINE DCOM- 20240117 LR - 20240117 IS - 1432-2307 (Electronic) IS - 0945-6317 (Linking) VI - 484 IP - 1 DP - 2024 Jan TI - Branchioma: immunohistochemical and molecular genetic study of 23 cases highlighting frequent loss of retinoblastoma 1 immunoexpression. PG - 103-117 LID - 10.1007/s00428-023-03697-1 [doi] AB - Branchioma is an uncommon benign neoplasm with an adult male predominance, typically occurring in the lower neck region. Different names have been used for this entity in the past (ectopic hamartomatous thymoma, branchial anlage mixed tumor, thymic anlage tumor, biphenotypic branchioma), but currently, the term branchioma has been widely accepted. Branchioma is composed of endodermal and mesodermal lineage derivatives, in particular epithelial islands, spindle cells, and mature adipose tissue without preexistent thymic tissue or evidence of thymic differentiation. Twenty-three branchiomas were evaluated morphologically. Eighteen cases with sufficient tissue were assessed by immunohistochemistry, next-generation sequencing (NGS) using the Illumina Oncology TS500 panel, and fluorescence in situ hybridization (FISH) using an RB1 dual-color probe. All cases showed a biphasic morphology of epithelial and spindle cells with intermingled fatty tissue. Carcinoma arising in branchioma was detected in three cases. The neoplastic cells showed strong AE1/3 immunolabeling (100%), while the spindle cells expressed CD34, p63, and SMA (100%); AR was detected in 40-100% of nuclei (mean, 47%) in 14 cases. Rb1 showed nuclear loss in >/= 95% of neoplastic cells in 16 cases (89%), while two cases revealed retained expression in 10-20% of tumor cell nuclei. NGS revealed a variable spectrum of likely pathogenic variants (n = 5) or variants of unknown clinical significance (n = 6). Loss of Rb1 was detected by FISH in two cases. Recent developments support branchioma as a true neoplasm, most likely derived from the rudimental embryological structures of endoderm and mesoderm. Frequent Rb1 loss by immunohistochemistry and heterozygous deletion by FISH is a real pitfall and potential confusion with other Rb1-deficient head and neck neoplasms (i.e., spindle cell lipoma), especially in small biopsy specimens. CI - (c) 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature. FAU - Bradova, Martina AU - Bradova M AUID- ORCID: 0000-0002-5829-5572 AD - Department of Pathology, Faculty of Medicine in Pilsen, Charles University, E. Benese 13, 305 99, Pilsen, Czech Republic. bradova@biopticka.cz. AD - Bioptic Laboratory, Ltd, Pilsen, Czech Republic. bradova@biopticka.cz. FAU - Thompson, Lester D R AU - Thompson LDR AD - Head and Neck Pathology Consultations, Woodland Hills, CA, USA. FAU - Hyrcza, Martin AU - Hyrcza M AD - Department of Pathology and Laboratory Medicine, University of Calgary, Calgary Laboratory Services, Foothills Medical Centre, Calgary, AB, Canada. FAU - Vanecek, Tomas AU - Vanecek T AD - Molecular and Genetic Laboratory, Bioptic Laboratory, Ltd, Pilsen, Czech Republic. FAU - Grossman, Petr AU - Grossman P AD - Molecular and Genetic Laboratory, Bioptic Laboratory, Ltd, Pilsen, Czech Republic. FAU - Michal, Michael Jr AU - Michal M Jr AD - Department of Pathology, Faculty of Medicine in Pilsen, Charles University, E. Benese 13, 305 99, Pilsen, Czech Republic. AD - Bioptic Laboratory, Ltd, Pilsen, Czech Republic. FAU - Hajkova, Veronika AU - Hajkova V AD - Molecular and Genetic Laboratory, Bioptic Laboratory, Ltd, Pilsen, Czech Republic. FAU - Taheri, Touraj AU - Taheri T AD - School of Medicine and Pathology Queensland, University of Queensland, Brisbane, Australia. FAU - Rupp, Niels AU - Rupp N AD - Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland. AD - Faculty of Medicine, University of Zurich, Zurich, Switzerland. FAU - Suster, David AU - Suster D AD - Department of Pathology, Rutgers University New Jersey Medical School, Newark, NJ, USA. FAU - Lakhani, Sunil AU - Lakhani S AD - School of Medicine and Pathology Queensland, University of Queensland, UQCCR, Herston, Australia. FAU - Nikolov, Dimitar Hadzi AU - Nikolov DH AD - Pathology Department, Regional Hospital Kolin, JSC, Kolin, Czech Republic. FAU - Zalud, Radim AU - Zalud R AD - Pathology Department, Regional Hospital Kolin, JSC, Kolin, Czech Republic. FAU - Skalova, Alena AU - Skalova A AD - Department of Pathology, Faculty of Medicine in Pilsen, Charles University, E. Benese 13, 305 99, Pilsen, Czech Republic. AD - Bioptic Laboratory, Ltd, Pilsen, Czech Republic. FAU - Michal, Michal AU - Michal M AD - Department of Pathology, Faculty of Medicine in Pilsen, Charles University, E. Benese 13, 305 99, Pilsen, Czech Republic. AD - Bioptic Laboratory, Ltd, Pilsen, Czech Republic. FAU - Agaimy, Abbas AU - Agaimy A AD - Institute of Pathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nurnberg (FAU), Comprehensive Cancer Center (CCC) Erlangen-EMN, Erlangen, Germany. LA - eng PT - Journal Article DEP - 20231114 PL - Germany TA - Virchows Arch JT - Virchows Archiv : an international journal of pathology JID - 9423843 RN - Thymoma, Familial RN - Thymic epithelial tumor SB - IM MH - Adult MH - Humans MH - Male MH - Female MH - *Branchioma/pathology MH - *Retinoblastoma/genetics/pathology MH - In Situ Hybridization, Fluorescence MH - *Soft Tissue Neoplasms/pathology MH - *Retinal Neoplasms MH - Molecular Biology MH - *Neoplasms, Glandular and Epithelial MH - *Thymoma MH - *Thymus Neoplasms OTO - NOTNLM OT - And neck OT - Branchioma OT - CD34 OT - Ectopic hamartomatous thymoma OT - Head OT - RET OT - Retinoblastoma 1 EDAT- 2023/11/14 12:43 MHDA- 2024/01/17 06:42 CRDT- 2023/11/14 11:07 PHST- 2023/09/28 00:00 [received] PHST- 2023/11/03 00:00 [accepted] PHST- 2023/10/25 00:00 [revised] PHST- 2024/01/17 06:42 [medline] PHST- 2023/11/14 12:43 [pubmed] PHST- 2023/11/14 11:07 [entrez] AID - 10.1007/s00428-023-03697-1 [pii] AID - 10.1007/s00428-023-03697-1 [doi] PST - ppublish SO - Virchows Arch. 2024 Jan;484(1):103-117. doi: 10.1007/s00428-023-03697-1. Epub 2023 Nov 14.