Case Report: SMARCB1 (INI-1)-Deficient Carcinoma of the Nasal Cavity with Pure Yolk Sac Tumor Differentiation and Elevated Serum AFP Levels

In adults, yolk sac tumors (YSTs) in the nasal cavity and paranasal sinuses are very rare. To date, only six cases have been reported in the English literature. YSTs in adults are often accompanied by cancer, teratocarcinosarcoma, and other malignant components. Here, we have reported a case of nasal tumor in a 55-year-old man with nasal obstruction and epistaxis. Morphologically, the tumor showed histological characteristics of pure YST. Immunohistochemical staining showed diffuse expression of SALL4, CDX2, and GPC-3 accompanied by sporadic expression of alpha-fetoprotein (AFP) and CD117. After 20 and 40 days of operation, the serum AFP level was 220.30 and 43.60 ng/mL (normal