Most esophageal carcinomas fall into one of two kinds: adenocarcinoma or squamous cell carcinoma. Although both present with painful and difficult swallowing, and both have a dismal prognosis, there are some significant differences between the two tumors.

Adenocarcinoma
Esophageal adenocarcinoma usually arises in Barrett esophagus. Risks include having documented dysplasia within Barrett’s (well, obviously!), smoking, obesity, and prior radiation therapy. As is the case for many malignant tumors, a diet rich in fresh fruits and vegetables helps decrease the risk of tumor formation. If you take a look at the standard American diet, it’s about as cancer-promoting as you can get. Anyway. Esophageal adenocarcinoma occurs most frequently in caucasians, and it’s way more common in men. It accounts for about half of all esophageal carcinomas (the other half being squamous cell carcinomas).

Esophageal adenocarcinoma usually occurs in the distal third of the esophagus (not a surprise, since that’s where Barrett’s is). It is a typical adenocarcinoma, as you can see in the image above, with abortive gland formation in most cases (a few cases have signet-ring morphology or small, poorly-differentiated cells).

Usually, by the time symptoms are noticed, the tumor has spread to nearby lymphatics and is already on its way to distant sites. The esophagus is particularly rich in lymphatics – so whether esophageal tumors are squamous cell carcinomas or adenocarcinomas, lymphatic spread is likely. Overall survival is accordingly dismal (less than 25% of patients survive past 5 years).

Squamous cell carcinoma
Squamous cell carcinoma of the esophagus is not related to Barrett esophagus (which makes sense, since the dysplasia in Barrett’s is in glandular cells, not squamous cells). Risk factors for squamous cell carcinoma include alcohol and tobacco use (both together are synergistically dangerous), poverty, caustic esophageal injury, achalasia, tylosis (a genetic disorder characterized by hyperkeratosis of the palms and soles and leukoplakia in the mouth), Plummer-Vinson syndrome (a condition occurring in patients with long-standing iron-deficiency anemia in which little webs of tissue can obstruct the esophagus) and frequent consumption of very hot beverages.

Squamous cell carcinoma doesn’t have a predilection for the distal third of the esophagus – in fact half occur in the middle third. Most cases start out with dysplastic epithelium that looks like a little whitish patch grossly. Eventually, they grow into polypoid masses that may obstruct the lumen of the esophagus. Microscopically, most cases are typical moderately- to well-differentiated squamous cell carcinomas (but a few have unusual cells, like spindle cells or basaloid cells).

Most of the time, by the time the tumor presents, it is already invasive . If, by chance, you catch it before it invades, the 5 year prognosis is 75%. However, if the tumor is metastatic, 5 year survival drops to 9%.