Sinonasal pure yolk sac tumor: a case report and literature review.

Extragonadal pure yolk sac tumor of sinonasal origin is very rare. We report herein a case with sinonasal yolk sac tumor in a 1 year and 3 months old girl. The initial complaint was persistent nasal bleeding for about 2 months. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a lobulated soft tissue mass in paranasal sinus that extended to oral cavity, nasopharynx, and oropharynx. The histology showed typical features of yolk sac tumor and the positive immunohistochemical staining of SALL4 and α-fetoprotein. After tumor excision, adjuvant chemotherapy of JEB regimen was prescribed. After the follow-up for 13-months, α-fetoprotein was normal and neither tumor progression nor metastasis was found. We review the previous literature and discuss the etiology, histology, treatment, and the prognosis of the rare sinonasal yolk sac tumor.