Parachordoma: an ultrastructural and immunohistochemical study

Area of Science:

• Oncology
• Pathology
• Soft Tissue Neoplasms

Background:

• Parachordoma is a rare soft tissue neoplasm.
• Distinguishing parachordoma from other tumors is crucial for accurate diagnosis and treatment.

Observation:

• A case of parachordoma in the left calf of a 19-year-old Chinese female is presented.
• The tumor displayed a multinodular growth pattern with round to oval cells, eosinophilic cytoplasm, and a myxoid matrix.
• Histological examination revealed nests of tumor cells, some with concentric arrangements, physaliferous-like cells, and undifferentiated spindle cells.

Findings:

• The myxoid matrix stained positive for chondroitin 4- and 6-sulphates and keratan sulphate.
• Ultrastructural analysis showed well-developed rough endoplasmic reticulum, intermediate filaments, and desmosome-like junctions.
• Immunohistochemistry revealed S-100 protein and vimentin positivity, with negativity for cytokeratin, EMA, CEA, and desmin.

Implications:

• The findings support the definition of parachordoma as a soft tissue neoplasm.
• This case contributes to understanding the histological, ultrastructural, and immunohistochemical characteristics of parachordoma.
• Accurate classification is essential for appropriate patient management and further research into these rare tumors.