Pathophysiology

Pathophysiology Study Guide

©2018 of 131 slowly, and remain localized. These cells do not spread and infect the surrounding tissues. The cells are derived from parent cells. These cells grow slowly through expansion. The benign neoplasm cells are mostly capsulated and do not metastasize. The shape of benign neoplasm cells resembles a non- capsulated polyp in the case of surface epithelia, while it is globular or ovoid shape surrounded by fibrous capsule when originated inside a solid organ. Benign neoplasm cells resemble the parent cells regarding cytoplasm and histology. Regarding cytology, these cells are mature and resemble the parent cells, which had minimum mitosis. Regarding histology, the arrangement of the benign cells is same as that of the originating cells. The stroma of these cells is in excess with few well-formed blood vessels. Moreover, the secondary changes among these cells are less common. The benign neoplasm cells do not generally recur once they are excised. These cells are not life- threatening, except if they are located in vital organs, tubular organs, produce hormones, or are capable of transforming into malignant neoplasm cells. Characteristics of Malignant Neoplasms Malignant neoplasm cells are formed from immature tissues, expand fast, and invade the surrounding cells, structures, and lymphatic and blood vessels. They are capable of forming metastatic (secondary) tumors. The shape of these cells depicts a mass inside a solid organ, which is irregular but non- capsulated, with infiltrative borders, and appears hard and grayish in color. The shape of the malignant neoplasm cells can take three forms at the epithelial surface: polypoid mass, ulcerative pattern, and infiltrative growth pattern. The polypoid mass looks like a cauliflower as it has a gray colored bulging mass and appears hard with an irregular surface at the outer side, with a broad base that is fixed. The ulcerative pattern is also known as malignant ulcer, which has irregular margins, raised and averted edges, and is rough and necrotic at the floor, while the base is fixed and indurated. Finally, with infiltrative growth pattern, the tumor is deeply infiltrating and fixed to the surrounding structures. These cells grow through expansion as well as infiltration. They originate from a single cell but metastasize. They have a huge potential to grow to a large size in a small timeframe. At the cut section, the malignant neoplasm cells show hemorrhage and necrosis. The cellular atypia of these cells shows the characteristics of a tumor. The stroma of malignant cells is poor with prominent vascularity, and secondary alterations are common. These cells are life-threatening and can recur even after excision. Some circumstances when malignant neoplasm cells cause death include destruction of the local organ after the local spread of cells, destruction of distant organs if the spread becomes distant, obstruction in hollow organs, like urinary bladder, Cachexia, and Paraneoplastic syndrome. Mechanisms of Metastasis Metastasis happens when the tumor or cancer cells move from their original site and infect distant cells in the body. The process of metastasis is complex and involves many steps before the cells can colonize. The cells detach from the primary tumor and penetrate the primary basement membranes by invading the tissues surrounding the initial graze. When the spread occurs within the blood vessel, it is a hematogenous spread, and if the penetration occurs through the lymph channels, it is known as a lymphatic spread. After penetrating these mediums, the tumor cells reach vital organs like the liver, brain, bones, or lungs. In vital organs, these tumor cells develop their colonies, and a new lesion is formed, which is fed by the newly formed blood vessels. The formation of these new blood vessels is Achieve Page 16

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