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Does CSF 1 overexpression or rearrangement influence biological behaviour in tenosynovial giant cell tumours of the knee?
Author(s) -
Mastboom Monique J L,
Hoek Daisy M,
Bovée Judith V M G,
Sande Michiel A J,
Szuhai Károly
Publication year - 2019
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/his.13744
Subject(s) - pigmented villonodular synovitis , pathology , giant cell , synovitis , in situ hybridization , fluorescence in situ hybridization , medicine , biology , gene expression , arthritis , gene , biochemistry , chromosome
Aims Localised‐ and diffuse‐type tenosynovial giant cell tumours ( TGCT ) are regarded as different clinical and radiological TGCT types. However, genetically and histopathologically they seem indistinguishable. We aimed to correlate CSF 1 expression and CSF 1 rearrangement with the biological behaviour of different TGCT ‐types with clinical outcome (recurrence). Methods and results Along a continuum of extremes, therapy‐naive knee TGCT patients with >3‐year follow‐up, mean age 43 (range = 6–71) years and 56% females were selected. Nine localised (two recurrences), 16 diffuse‐type (nine recurrences) and four synovitis as control were included. Rearrangement of the CSF 1 locus was evaluated with split‐apart fluorescence in‐situ hybridisation ( FISH ) probes. Regions were selected to score after identifying CSF 1 ‐expressing regions, using mRNA ISH with the help of digital correlative microscopy. CSF 1 rearrangement was considered positive in samples containing >2 split signals/100 nuclei. Irrespective of TGCT ‐subtype, all cases showed CSF 1 expression and in 76% CSF 1 rearrangement was detected. Quantification of CSF 1 ‐expressing cells was not informative, due to the extensive intratumour heterogeneity. Of the four synovitis cases, two also showed CSF 1 expression without CSF 1 rearrangement. No correlation between CSF 1 expression or rearrangement with clinical subtype and local recurrence was detected. Both localised and diffuse TGCT cases showed a scattered distribution in the tissue of CSF 1 ‐expressing cells. Conclusion In diagnosing TGCT , CSF 1 mRNA ‐ ISH , in combination with CSF 1 split‐apart FISH using digital correlative microscopy, is an auxiliary diagnostic tool to identify rarely occurring neoplastic cells. This combined approach allowed us to detect CSF 1 rearrangement in 76% of the TGCT cases. Neither CSF 1 expression nor presence of CSF 1 rearrangement could be associated with the difference in biological behaviour of TGCT .