Abstract
BACKGROUND: Extragonadal yolk sac tumors (YSTs) are rare, with only a low reported tumor occurrence outside the gonads locally and abroad. Extragonadal YSTs are usually a diagnostic challenge, because they are infrequent, but also because a thoughtful and detailed differential diagnostic process must be performed. CASE SUMMARY: Here we present a case of an abdominal wall YST in a 20-year-old woman admitted with a tumor in the lower abdomen close to the umbilicus. The tumorectomy was performed. The histological examination revealed characteristic findings such as Schiller-Duval bodies, loose reticular structures, papillary structures, and eosinophilic globules. According to the immunohistochemical staining, the tumor tissue was positive for broad-spectrum cytokeratin, Spalt-like transcription factor 4, glypican-3, CD117, and epithelial membrane antigen. Based on the clinical information, histological features, and immunohistochemical staining profile, the tumor was diagnosed as a YST present in the abdominal wall. CONCLUSION: Based on the clinical information, histological features, and immunohistochemical staining profile described above, the tumor was diagnosed as a primary YST in the abdominal wall.