parachordoma

parachordoma

A benign, ultrarare (40 reports in the world literature), circumscribed, non-encapsulated tumour that develops on the extremities adjacent to tendons, synovium or osseous structures.
References in periodicals archive ?
(9) Individual tumor cells are often round to oval with scant or moderate eosinophillic cytoplasm and pleomorphic nuclei with rhabdoid and epitheloid cells scattered at periphery.9 ESMC expresses neuroendocrine differentiation with strong immunopositivity for vimentin and synaptophysin (7) and weak or focal positivity for EMA and S-100.7 Myxoid matrix with lobulated neoplastic cells is also seen in chordoma, parachordoma, chordoid meningiomas, and myxopapillary ependymoma.
(1) Primary nasopharyngeal ESMC can often be misdiagnosed with squamous cell carcinoma nasopharynx, melanomas, lymphomas, soft tissue sarcomas, Ewing sarcoma, skeletal chondrosarcomas, chordomas, parachordomas, myoepithelial carcinoma, myxopapillary ependymomas, chordoid meningiomas, and myxoid liposarcoma.
Werker, "Parachordoma: a very rare tumour of the hand," Journal of Hand Surgery (European Volume), vol.
Several differential diagnoses should be excluded, such as myxoid chondrosarcoma, myxoid liposarcoma, and parachordoma [10], but the presence of physaliphorous cells and the peculiar immunohistochemical features, for example, positivity for cytokeratins, vimentin, epithelial membrane antigen (EMA), and S-100 protein, can be helpful for achieving the correct one.
Parachordoma has trisomy 15, monosomy 1.16.17 and no mature fat cells.
Miettinen, "Parachordoma: a clinicopathologic and immunohistochemical study of four cases of an unusual soft tissue neoplasm," Annals of Diagnostic Pathology, vol.
DIFFERENTIAL DIAGNOSIS: Parachordoma and Myxoid chondrosarcoma can be considered.