Low-grade chondrosarcoma (LGC) is a very rare intracranial tumor, particularly in the sellar area. Herein, we describe an unusual case of LGC occurring in the sellar area. A 52-year-old man presented with diminution of vision for more than 3 months, but did not exhibit headaches reported in previous cases. MRI showed that the maximum size of the tumor was 7 cm on the left side of the saddle. We characterized the specific pathological characteristics. Histologically, the tumor had polypoid areas and a lobulated growth pattern under low-power examination. At high magnification, the tumor consisted of small cells with hyperchromatic nuclei in the cartilage matrix, with an alternating loose hypocellular zone and rich myxoid area. In our case, LGC needed to be distinguished from chordoma. Immunohistochemically, the tumor cells showed diffuse positivity for S-100 and vimentin, IDH1 was weakly cytoplasm positive. The Ki-67 labeling index was less than 5%. Additionally, AE1/3, EMA, and CK19 were negative, which could be used to exclude chordoma. This case report expands the literature on LGC and will help clinicians and pathologists better understand this entity.
Keywords: differential diagnosis; low-grade chondrosarcoma; saddle area.
© 2019 Zhang et al.