The Distinction Between Carcinoma and Sarcoma

Carcinoma is a malignant tumor derived from epithelial tissue, while sarcoma is a malignant tumor derived from mesenchymal tissue; this is the most fundamental distinction between the two.

The two also differ considerably in age of onset and incidence. Carcinoma is more common, with an incidence about nine times that of sarcoma, and occurs mostly in middle-aged and elderly people over 40; sarcoma is less common and occurs mostly in adolescents and young adults.

Gross features: the cut surface of carcinoma is relatively friable, gray-white, dry, and coarsely granular, often accompanied by necrosis; the cut surface of sarcoma is relatively soft, gray-red, moist, and delicate, fish-flesh-like, often accompanied by bleeding.

Histological features: carcinoma cells form solid cords and nests (carcinoma nests), with a clear boundary between parenchyma and stroma, and fibrous tissue is often proliferated; sarcoma cells are diffusely distributed, with an unclear boundary between parenchyma and stroma, the stroma is rich in blood vessels, and fibrous tissue is scant.

Reticular fibers: carcinoma nests are surrounded by reticular fibers, with no reticular fibers between carcinoma cells; reticular fibers are present between sarcoma cells.

Metastatic route: carcinoma mostly metastasizes via the lymphatic route; sarcoma mostly metastasizes via the hematogenous route.