Adenocarcinoma Origin: glandular tissue. Sites: endocrine, exocrine glands, mucus membranes, GIT, endometrium. Gross: in solid organsirregular infiltrative growth, in hollow organsfungating, infiltrating or ulcerating growth. Microscopically: irregular glands in size and shape,lined by malignant cells and separated by C.T. stroma. Grading: depends on tubule formation, number of mitoses and irregular nuclear pattern.
Mucoid carcinoma Origin: from glandular epithelium. Sites: mostly in GIT. Grossly: appears as soft gelatinous mass. Microscopicaly:1-Mucoid carcinoma: mucoid differentiation in an adenocarcinoma rupture of cells release of large amount of extra-cellular mucin.2-Signet cell carcinoma: cells are distended with intracellular mucin--. Signet ring cells with minimal extrapcellular mucin.
Basal cell crcinoma ((Rodent ulcer Def: locally malignant tumor arising from the basal cell layer of epidermis. Sites: skin areas exposed to sun as in face. Gossly: starts as a papule rodent ulcer ( raised everted edge,rough and necrotic floor, indurated edge). Histologically: invasion of the dermis by variable sized masses formed of malignant basaloid cells that form palisade appearance at the periphery.