Donate
Menu

Main Content

Dedifferentiated Chordoma

Dedifferentiated chordoma is a chordoma with a biphasic appearance, characterized by conventional chordoma and high-grade sarcoma.

Symptoms & Causes

Introduction

Dedifferentiated chordoma is a rare subtype of chordoma that includes both conventional chordoma and a high-grade sarcoma component.

Reference
WHO Classification of Tumours Editorial Board. Soft tissue and bone tumours [Internet]. Lyon (France): International Agency for Research on Cancer; 2020 [cited 2024 09 11]. (WHO classification of tumours series, 5th ed.; vol. 3). Available from: https://tumourclassification.iarc.who.int/chapters/33.

Related Terminology
None

Subtype(s)
None

Symptoms

The symptoms are similar to those of conventional chordoma, although progression may be more rapid. Pain and site-related neurological symptoms are common. Dedifferentiated chordoma may present de novo or at the location of a previously resected conventional chordoma.

Localization

The locations are similar to those of conventional chordoma, predominantly in sacrococcygeal sites.

Epidemiology

Dedifferentiated chordoma is the rarest notochordal tumor subtype, with only case reports and small series published.

Etiology

Unknown

Diagnosis & Treatment

Staging

Staging is according to bone sarcoma protocols.

Pathogenesis

See section on conventional chordoma.

Macroscopic Appearance

The tumor presents as a large mass with a biphasic appearance. The dedifferentiated component has the gross features of a high-grade sarcoma with a solid surface, juxtaposed to a gelatinous and myxoid conventional chordoma.

Histopathology

The distinguishing characteristic is the simultaneous presence of a conventional chordoma and a high-grade spindle and/or pleomorphic sarcoma. Osteosarcomatous and rhabdomyosarcomatous differentiation can be seen. The two components are usually abruptly separated, but they can be intermingled.

Immunohistochemistry
The dedifferentiated component can show focal cytokeratin expression but does not express brachyury. Specific lineages, such as rhabdomyoblastic, should be supported by immunohistochemical expression of desmin and myogenin.

Differential diagnosis
The differential diagnosis includes dedifferentiated chondrosarcoma.

Cytology

Not clinically relevant

Prognosis and Prediction

The prognosis is poor; the metastatic rate and mortality are high. The benefits of chemotherapy or radiotherapy seem negligible. Surgery is the only option.

Clinical Features

Diagnostic Molecular Pathology

No diagnostic molecular markers have been reported.

Essential and Desirable Diagnostic Criteria

Essential: bone tumor with compatible imaging; conventional chordoma (histologically or by history) plus high-grade sarcoma.

ribbon

Make a Donation

Help us move closer to a world where people do not die from sarcoma

Make a Donation
ribbon

section