Fig. 3.

Representative examples of SMARCB1-deficient sinonasal adenocarcinoma. A variable admixture of glands, sieve-like pattern or pseudocribriform structures embedded within abundant mucoid stroma, note uniformly high-grade cytology. B some tumors display pure yolk sac-like morphology with bland-looking cells. C this predominantly solid tumor shows numerous mini-lumina and large eosinophilic cells, highly reminiscent of apocrine salivary duct carcinoma and high-grade non-intestinal adenocarcinoma. D transition from adenocarcinoma (left) to solid undifferentiated component (right) may be seen. E strong diffuse reactivity with SALL4 combined with pure yolk sac-like pattern, as in this case, represents a major pitfall. F complete loss of SMARCB1 is limited to the neoplastic cells