Primary sinonasal chondroid chordoma in a pediatric patient: a diagnostic challenge

Background Chordomas are rare, malignant tumors typically centered in midline structures such as the clivus and sacrum, with peak prevalence in the fourth decade. Clival chordomas may secondarily extend to involve the nasopharynx and nasal cavity; however, primary extra-osseous chordomas are even more uncommon. We present an unusual case of a primary sinonasal chondroid chordoma arising from the maxillary sinus in a 5-year-old child. This is the second case of primary sinonasal chordoma reported in the literature so far, after Tao ZZ et al. and the first case of the chondroid variant.Case presentation A 5-year-old male presented with right-sided nasal obstruction, nasal congestion, and snoring for 2 months. Physical examination showed a reddish polypoidal mass in the right nasal cavity obstructing the choana with nasal septal deviation toward left side. Radiological examination with CT confirmed the presence of a well-defined, heterogeneously hyperdense lobulated mass in right maxillary sinus extending into right nasal cavity with intralesional coarse calcifications. MRI revealed expansile solid altered signal intensity mass, which appears to be isointense on T1-weighted imaging (T1WI) and heterogeneously hyperintense on T2-weighted imaging (T2WI) with a heterogeneous honeycomb pattern of enhancement. Differentials considered were rhabdomyosarcoma, nasopharyngeal carcinoma, and neuroblastoma metastasis. However, the lesion was pathologically proven as a chondroid chordoma. No association with skull base or clival lesion was found on review.Conclusions Primary sinonasal chordomas are rare in occurrence but should be considered a differential for sinonasal masses in the presence of characteristic MRI features, despite their uncommon location.