Poorly differentiated chordoma in head and neck:Clinicopathological and prognostic analysis

HE Wenyuan; LAI Xuwen; ZENG Weipeng; YU Ling; WANG Zhuocai; WANG Wei

doi:10.3969/j.issn.1009-0460.2024.05.015

Abstract：Objective To investigate the clinicopathological characteristics,differential diagnosis and prognosis of poorly differentiated chordoma(PDC)in the head and cervical spine.Methods Clinical and image data of 6 cases of PDC between January 2006 and June 2022 in the General Hospital of Southern Theater Command were collected.H&E,immunohistochemical staining,and fluorescence in situ hybridization(FISH)detection were performed.Results The 6 patients included 5 female and 1 male with the age ranging from 4 to 37 years(median age 15 years).Four PDCs located at the cervical spine and 2 at skull base.Microscopically,the epithelioid or spindle tumor cells were arranged in nests or diffuse sheets with central necrosis.Some tumor cells showed rhabdoid.The nuclei were vesicular,with obvious nucleoli and variable mitoses.Rich lymphocytes,plasma cells and neutrophils infiltrated in the stroma.The tumor cells of 6 PDCs were diffuse positive for CK,EMA,Vimentin and Brachyury.SMARCB1/INI1 expression loss was detected in all cases.The Ki-67 index ranged from 10％to 50％.Five patients underwent sub-total tumor resection,and 1 case only received chemo-radiotherapy.Five patients were followed up and died at 2-17 months after first diagnosis(median survival time:5 months).Conclusion The cervical spine is also the preferentially affected site of PDC.PDC is easily misdiagnosed for the atypical histological characteristics.However,the same immunophenotype as classical chordoma and expression loss of SMARCB1/INI1 make definite diagnosis of PDC possible.PDC is prone to recur and metastasize with a poor prognosis.