MUC5AC and neoplasm: High-grade GCC manifests through five predominant patterns: the diffused infiltration of signet ring-like/goblet-like cells either as single cells or in abortive tubules, fusion of clusters leading to the formation of large anastomosing structures or extensive aggregates, infiltrative single-file or anastomosing cords of tumor cells with high-grade nuclei, gland-forming adenocarcinoma often displaying a micro-glandular growth pattern of tubules with high-grade nuclei, and a solid sheet-like growth lacking clustered formations and exhibiting minimal to no intracytoplasmic mucin.