Which tumor type is primarily associated with glandular structures?

Adenocarcinoma is a tumor type that originates from glandular structures, making it the correct answer in this context. This type of cancer arises from epithelial cells, specifically those that have glandular functions, such as producing secretions. Glandular structures can be found in various organs, including the mammary glands, salivary glands, pancreas, and intestines.

Adenocarcinomas are characterized by their ability to produce mucins or other substances associated with glandular cells. This distinction is crucial as it informs the behavior of the tumor, potential patterns of spread, and treatment options. For instance, adenocarcinomas can exhibit specific histological features such as the formation of gland-like structures and may also have particular immunohistochemical markers that differentiate them from other tumor types.

Carcinomas, while also deriving from epithelial cells, encompass a broader category that includes both adenocarcinomas and non-glandular types such as squamous cell carcinomas. Sarcomas, on the other hand, are neoplasms arising from mesenchymal tissues, and melanomas originate from melanocytes, which are pigment-producing cells in the skin. These other tumor types are not primarily associated with glandular structures,