Adenosquamous Carcinoma: Definition

Adenosquamous carcinoma is a type of cancer that contains two distinct cell types within the same tumor: glandular cells and squamous cells. Glandular cells normally produce and release substances such as mucus or enzymes, while squamous cells form the flat surface layers of the skin and line many internal organs. Because it contains both cell types, adenosquamous carcinoma shares features with two better-known cancers — adenocarcinoma (a cancer of glandular cells) and squamous cell carcinoma (a cancer of squamous cells) — but is recognized as a distinct diagnosis because both components are present together in meaningful amounts.

Where does adenosquamous carcinoma develop?

Adenosquamous carcinoma can develop in any organ that contains both glandular and squamous cells, or in which cells have the capacity to develop along either pathway. It is most commonly found in the lung, pancreas, cervix, stomach, esophagus, skin, and bladder. It is generally considered a rare cancer type in each of these locations.

What does adenosquamous carcinoma look like under the microscope?

When a pathologist examines adenosquamous carcinoma under the microscope, they see a mixture of two distinct cell populations within the same tumor:

Glandular cells — cube- or column-shaped cells arranged into gland-like structures, often associated with mucin production. Mucin is the slippery substance produced by glandular cells and can be found inside the cells or in the surrounding tissue.
Squamous cells — flat, pink-staining cells that may form layered sheets or show characteristic features of squamous differentiation.

Both components must be present in recognizable amounts for the pathologist to diagnose adenosquamous carcinoma rather than classifying the tumor as purely adenocarcinoma or purely squamous cell carcinoma. Additional tests, such as immunohistochemistry or molecular testing, are sometimes used to confirm the diagnosis.

How is adenosquamous carcinoma graded?

Grade describes how abnormal the tumor cells look compared to normal cells and helps predict how quickly the cancer may grow and behave:

Well differentiated (low grade) — tumor cells retain recognizable features of both glandular and squamous cells and tend to grow more slowly.
Moderately differentiated (intermediate grade) — cells show a mix of normal and abnormal features.
Poorly differentiated (high grade) — cells look very abnormal and tend to be more aggressive.
Undifferentiated (high grade) — cells bear almost no resemblance to normal tissue and behave most aggressively.

The grading criteria vary by organ involved, and your pathology report will state the specific grade assigned to your tumor.

What does an adenosquamous carcinoma diagnosis mean?

Adenosquamous carcinoma is generally considered an aggressive cancer. In many locations, it tends to behave more aggressively than either pure adenocarcinoma or pure squamous cell carcinoma arising from the same organ. This is partly because the glandular component carries a higher risk of spreading to distant sites.

The prognosis and treatment options depend on where the cancer originated, the grade, the stage (how far the cancer has spread), and the patient’s overall health. Treatment typically involves surgery, radiation, chemotherapy, or a combination of these, and may also include targeted therapy or immunotherapy depending on the organ involved and any biomarker results. Your oncologist and surgeon will discuss the specific options that apply to your situation.

Questions to ask your doctor

What grade is my adenosquamous carcinoma, and has it spread to lymph nodes or other parts of the body?
Was biomarker or molecular testing performed, and are there targeted therapy or immunotherapy options available for me?
What treatment plan is recommended, and what outcomes can I expect?