Which of the following is a common type of solid tumor?

Breast cancer is classified as a common type of solid tumor because it originates in the cells of the breast tissue and forms a mass or lump, which is characteristic of solid tumors. Solid tumors are distinct masses of tissue that typically develop from the uncontrolled growth of cells in a specific organ or tissue.

In contrast, leukemia and myeloma are types of blood cancers. Leukemia arises from the bone marrow and results in the overproduction of abnormal white blood cells, while myeloma affects plasma cells in the bone marrow. These blood cancers do not form solid masses but instead involve the proliferation of cells in the bloodstream or within the bone marrow.

Lymphoma, while it can involve solid masses in lymph nodes, is generally categorized as a hematologic malignancy and not as a solid tumor in the same way breast cancer is defined, as it typically affects the lymphatic system rather than a specific solid organ. Thus, breast cancer stands out as the common type of solid tumor among the options presented.