Extra‐axial skeletal poorly differentiated chordoma: a case report

Abstract

Chordoma is a rare, malignant bone tumour showing notochordal differentiation and expressing brachyury on immunohistochemistry, occurring along the spinal axis, from the skull base to coccyx. Rare extra-axial cases have been described in literature 1 .

Recurrent loss of chromosome 22 and SMARCB1 deletion in extra‐axial chordoma: A clinicopathological and molecular analysis

“…The term “parachordoma” has been largely abandoned and tumors with morphological resemblance to chordoma as above and metastatic carcinomas can be readily distinguished by absence of brachyury expression and other immunohistochemical and molecular findings 15 . To date, 17 publications with a total of 26 brachyury‐positive extra‐axial chordoma cases have been reported in the English‐language literature, most of them as case reports and one case series comprising six extra‐axial chordoma cases 3,12,15–29 . In these cases, the gross and microscopic appearance, immunohistochemical phenotype, and clinical course of the extra‐axial chordoma were identical to those of a midline chordoma, except that extra‐axial chordoma can occur at younger ages.…”

“…in the English-language literature, most of them as case reports and one case series comprising six extra-axial chordoma cases. 3,12,[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] In these cases, the gross and microscopic appearance, immunohistochemical phenotype, and clinical course of the extra-axial chordoma were identical to those of a midline chordoma, except that extra-axial chordoma can occur at younger ages. While karyotyping has shown loss of chromosome 22 in a case of parachordoma, 30 to the best of our knowledge, there have been no SNP array analysis describing genetic alterations in extra-axial chordoma thus far.…”

“…39 Extra-axial poorly differentiated chordoma is exceptionally rare with a single published case report of a 67-year-old female who presented with a knee mass with destruction of the medial cortex of metadiaphysis of distal femur and a large extraosseous soft tissue mass. 21 As chordomas in general belong to the C-class group, we utilized This was a biopsy material and the partial loss of INI1 could be related to the decalcification. In the four cases involving bone, our pancytokeratin showed patchy positivity which is likely related decalcification effect as our two soft tissue extra-axial chordomas showed expected diffuse positivity.…”

“…39 Extra-axial poorly differentiated chordoma is exceptionally rare with a single published case report of a 67-year-old female who presented with a knee mass with destruction of the medial cortex of metadiaphysis of distal femur and a large extraosseous soft tissue mass. 21 As chordomas in general belong to the C-class group, we utilized cases suggest that this is a crucial genetic alteration in extra-axial chordomas. In this small series, we did not find any evidence of chromothripsis, unlike conventional chordoma.…”

Myxoepithelioid tumour with chordoid features: a clinicopathological, immunohistochemical and genetic study of 14 cases of SMARCB1/INI1‐deficient soft‐tissue neoplasm

“…Brachyury is a transcription factor in the T-box group and is highly specific for chordoma 19,20 ; it is diffusely positive in this condition. [21][22][23] Poorly differentiated chordoma (PC) also shows diffuse positivity for brachyury, [24][25][26] with complete loss of 24 One extra-axial PC case has been described, but showed diffuse positivity for brachyury, 27 in contrast to METC. In addition, PC shows mild to moderate nuclear pleomorphism, abundant eosinophilic cytoplasm, and geographical necrosis.…”