Clinicopathologic features of four rare types of chordomas, confirmed by brachyury immunostaining

A wide clinicopathologic spectrum of a chordoma exists. Brachyury constitutes as its most useful diagnostic immunohistochemical (IHC) marker.

During a 7-year-period, 4 unusual histopathologic types of chordomas were identified. Immunohistochemistry was performed by polymer technique.

Clinicopathologic features of the 4 cases are as follows: Cases 1 and 2: Two tumors occurred in the sacrococcygeal and lumbosacral regions of a 42-year-old male and a 34-year-old female, respectively. Histopathologic examination showed areas of classical chordoma; juxtaposed to a high-grade, spindle cell sarcoma. By IHC, cytokeratin (CK), epithelial membrane antigen (EMA), S-100 protein, and brachyury were found to be distinctly positive in the differentiated chordomatous areas. Both these cases were diagnosed as dedifferentiated chordomas. The first patient, postresection and adjuvant radiation therapy (RT), died after 14 months of therapy. Case 3: A 58-year-old male presented with pain in his sacral region and urinary incontinence. Imaging disclosed a sacral mass. Histopathologic examination showed physaliphorous cells intimately admixed with, markedly pleomorphic cells, scattered mitotic figures, and focal tumor necrosis. By IHC, the tumor cells were positive for CK, AE1/AE3, S-100 protein, brachyury, and INI1/SMARCB1. The diagnosis of a poorly differentiated chordoma was offered. Despite surgical resection and adjuvant RT, the patient died within 18 months. Case 4: A 58-year-old male presented with a soft tissue lesion in his left leg. Histopathologic examination showed physaliphorous cells, embedded in a myxohyaline stroma. By IHC, the tumor cells were positive for EMA, S-100 protein, brachyury, and INI1. Diagnosis of an extra-axial, soft tissue chordoma was offered.

These four unusual chordomas, confirmed by brachyury immunoexpression, constitute as one of the first such documentation from our country, revealing a wide clinicopathologic spectrum of chordomas. Dedifferentiated and poorly differentiated chordomas are associated with an aggressive clinical course. Further diagnostic implications are discussed herewith.