adenocarcinoma
Meaning of adenocarcinoma: The name describes what the tumor is made of rather than where it grew, which is why it appears in reports from so many organs.
Definition of adenocarcinoma
Adenocarcinoma is a cancer arising from glandular cells, the secretory cells that produce mucus, hormones, digestive juices or other fluids. Any organ containing such cells can host one, so a single name covers tumors of the lung, colon, pancreas, stomach, breast and prostate. What unites them is the cell of origin and the gland-forming pattern seen under the microscope.
How is it recognized?
Under the microscope the tumor cells attempt to recreate the structure they came from, arranging themselves into tubes, ducts or gland-like spaces, often with mucus visible inside or within the cells. Special stains highlight that mucus, and antibody stains against particular proteins confirm the type. Those same stains help answer a common problem: when a deposit is found in the liver or a lymph node, its pattern of markers often points back to the organ the tumor started in. Grading describes how closely the tumor still resembles normal glands, from well differentiated, where the structure is obvious, to poorly differentiated, where the resemblance is almost gone.
How does it differ from the other carcinomas?
| Type of carcinoma | Cell of origin | Common sites |
|---|---|---|
| Adenocarcinoma | Glandular, secretory cells | Lung, colon, pancreas, stomach, breast, prostate |
| Squamous cell | Flat lining cells that make keratin | Skin, mouth, esophagus, cervix, lung |
| Small cell | Neuroendocrine cells | Lung, less often elsewhere |
| Urothelial | Lining of the urinary tract | Bladder, ureter, renal pelvis |
Why does the distinction matter?
It changes what happens next. In the lung, adenocarcinoma is the subtype in which targetable genetic changes are most often found, so tissue is routinely sent for molecular testing, while squamous tumors follow a different pathway. In the esophagus, the two subtypes carry different risk factors: adenocarcinoma follows long-standing reflux and the lining change it causes, while squamous carcinoma tracks with smoking and alcohol. In the colon and in prostate cancer, adenocarcinoma is so nearly universal that the word is often dropped from everyday speech and simply assumed.
Used in a sentence
Biopsy of the lung mass confirmed a diagnosis of adenocarcinoma.
Good to know
Adenocarcinoma is distinguished from squamous cell carcinoma by its glandular pattern under the microscope, a distinction that influences which molecular tests are performed and which treatments are considered.
Word origin
Where “adenocarcinoma” comes from
Formed from aden-, from Greek aden, meaning gland, with carcinoma, from karkinos, meaning crab, and -oma, meaning tumor.