HMGA2 and testicular yolk sac tumor: Because frequent high-level expression of HMGA2 was observed in individual tumor types, some authors have demonstrated HMGA2 positivity by IHC as a diagnostic feature for the diagnosis of pleomorphic adenoma and carcinoma ex pleomorphic adenoma of salivary glands [41], aggressive vulvovaginal angiomyxoma [42, 43], testicular yolk sac tumor [44], lipoma [45], uterine carcinoma [46], esophageal squamous cell carcinoma [47], follicular thyroid carcinoma [48], and dedifferentiated liposarcoma [49].