Chondrosarcoma with Target-Like Chondrocytes: Update on Molecular Profiling and Specific Morphological Features

Povýšil, Ctibor; Hojný, J.; Kaňa, M.

doi:10.14712/fb2022068030112

Folia Biologica > Archive > 2022, Vol. 68 > Issue 3 > Chondrosarcoma with Target-Like…

Fol. Biol. 2022, 68, 112-124

https://doi.org/10.14712/fb2022068030112

Chondrosarcoma with Target-Like Chondrocytes: Update on Molecular Profiling and Specific Morphological Features

Ctibor Povýšil¹, J. Hojný¹, M. Kaňa²

¹Institute of Pathology, First Faculty of Medicine, Charles University and General University Hospital in Prague, and Institute of Postgraduate Studies, Prague, Czech Republic
²Department of Otorhinolaryngology, Head and Neck Surgery, First Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic

Received May 2022
Accepted September 2022

This is the first histological and molecular analysis of two chondrosarcomas with target-like chondrocytes that were compared with a group of conventional chondrosarcomas and enchondromas. The unique histological feature of target-like chondrocytes is the presence of unusual hypertrophic eosinophilic APAS-positive perichondrocytic rings (baskets). In the sections stained with Safranin O/Fast green, the outer part of the ring was blue and the material in the lacunar space stained orange, similarly to intercellular regions. Immunohistochemical examination showed strong positivity for vimentin, factor XIIIa, cyclin D1, osteonectin, B-cell lymphoma 2 apoptosis regulator (Bcl-2), p53 and p16. The S-100 protein was positive in 25 % of neoplastic cells. Antibodies against GFAP, D2-40 (podoplanin), CD99, CKAE1.3 and CD10 exhibited weak focal positivity. Pericellular rings/baskets contained type VI collagen in their peripheral part, in contrast to the type II collagen in intercellular interterritorial spaces. Ultrastructural examination revealed that pericellular rings contained an intralacunar component composed of microfibrils with abundant admixture of aggregates of dense amorphous non-fibrillar material. The outer extralacunar zone was made up of a layer of condensed thin collagen fibrils with admixture of non-fibrillar dense material. NGS sequencing identified a fusion transcript involving fibronectin 1 (FN1) and fibroblast growth factor receptor 2 (FGFR2) at the RNA level. At the DNA level, no significant variant was revealed except for the presumably germline variant in the SPTA1 gene.
Erratum to this article was published in: Folia Biologica, 2022, 68, (5-6): 211–211. https://doi.org/10.14712/fb2022068050211

Keywords

cartilage tumour, chondrocytes with thick pericellular rings, target-like chondrocyte, immunohistochemistry, electron microscopy, FN1-FGFR2 gene fusion.

Funding

This study was supported by the Ministry of Health, Czech Republic (Conceptual development of research organization 64165, General University Hospital in Prague) and by Charles University (Project UNCE204065).