Parapharyngeal liposarcoma: a case report

BACKGROUND Parapharyngeal liposarcoma is a very rare malignant tumor that often causes nonspecific clinical symptoms, such as progressive dysphagia, globus sensation and/or respiratory disturbances. The combination of radiological imaging techniques and histopathological analysis provides information for diagnosis; however, the pathogenesis is still uncertain. CASE PRESENTATION A 30-year-old male patient presented with a pharyngeal cavity mass, which had been present for 2 years. The clinical syndrome included obstructive sleep apnea symptoms (i.e., respiratory disturbances, excessive daytime somnolence, and headache) and difficulty swallowing. The radiological examination (CT) demonstrated that there was a low-density irregular solid lesion on the posterior wall of the oropharynx and laryngopharynx, which descended to the superior mediastinum and extended to the left parapharyngeal space and sternocleidomastoid muscle. The boundaries of the lesion were clear, and the lesion's density was nonuniform. Several septations inside the lesion were observed. The CT values of the lesion at the epiglottis and the vocal folds were 11 HU and minus 30 HU, respectively. After enhanced scanning, there was no apparent enhancement of the lesion: the surrounding tissue and blood vessels were squeezed and shifted, but the neighboring sclerotin of the cervical vertebrae was not invaded. The mass was removed via a transcervical approach, resulting in a complete amelioration of the patient's symptoms. Interestingly, immunohistochemistry showed that the tumor cells expressed members of the B7 superfamily, including B7-H1, B7-DC and B7-H3. In addition, the expression of TIM-containing molecules, including TIM-3 and TIM-4, was observed. CONCLUSIONS CT and MRI demonstrated that the mass was a parapharyngeal liposarcoma. Furthermore, carcinoma-associated B7 and TIM-containing molecules were observed in the tissue, indicating that these molecules are most likely active in the pathogenesis of this disease. VIRTUAL SLIDES The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1907794973876202.