Histology:
The histopathological result of the biopsy and the first resection showed a spindle-cell, partly myxoid tumor. The tumor cells are repeatedly arranged in trains or bundles, also in a vertebral arrangement. Cells had ovoid to elongated nuclei with moderate nuclear hyperchromasia and overall low nuclear pleomorphism. The tumor reached the ink-marked resection margin in several places. Immunohistochemically, there was a clear positivity for CD34 and FGFR1-CAPRIN1 fusion which was detected by RNA panel sequencing. The fusion described above has not been described in the literature so far. The tumor was classified as a spindle-cell tumor with intermediate malignancy.