Interstitial tumors in Nadet's body
A Voyager officer suffering from several tumors
A tumor was an abnormal proliferation of cells in living tissue or organs.
In 2151, Doctor Phlox found interstitial tumors in Nadet's system as a result of lung cancer. He recommended a series of cytolytic injections for her as the malignancy had spread into her lymphatic system. (ENT: "Terra Nova")
Under certain conditions, people were known to alter their blood pressure, lower their body temperature, and manifest tumors as a result of psychological stimuli. (DS9: "Things Past")
Due to the tests and experiments by the Caretaker, Harry Kim and B'Elanna Torres suffered from tumorous growths on their body. (VOY: "Caretaker")
The call sheets for the day of filming are listing "tumorous growths" in the makeup and hair section" for the actors.
Cancer could be found in the form of a tumorous growth. Ptera, a Vhnori, had a cancerous tumor on her brain stem in 2371 until it was removed by The Doctor on the USS Voyager. (VOY: "Emanations")
A female crewmember aboard the Voyager suffered from tumor growths as a result of the hidden Srivani experiments. (VOY: "Scientific Method")