Malignant lesions of esophagus
Squamous cell carcinoma of esophagus is one of the most common fatal malignant neoplams involving it. This condition accounts for nearly 90% of all esophageal cancers.
There is a great geographic variations in occurrence of these lesions. High risk areas have been identified as Northern Iran, Central Asian republics of the former Soviet Union, Northern China and South Africa.
Etiology & Pathogenesis:
This has not been clearly defined. As usual smoking & alcohol consumption have been implicated. Environmental factors have been postulated to play a greater role especially in high risk zones. Consumption of diet that are low in fruits and vegetables have been known to cause widespread vitamin deficiency which can predispose to esophageal squamous cell carcinoma. People in high endemic zones are known to consume large amounts of pickled vegetables without the use of salt or vinegar. This can lead to fermentation of the pickle causing mutagens to be released. Some of the common mutagens implicated include: benzopyrenes and N-nitroso compounds.
Most common symptom is dysphagia. This is usually progressive in nature, ultimately can become absolute dysphagia.
Premalignant lesions of esophagus:
Squamous cell dysplasia of esophageal mucosa is considered to be precancerous in nature. This is a common histological finding adjacent to invasive cancers.
Dysplasia is defined morphologically by the presence of abnormal cells which couuld include the basal layer, with extensions to varying portions of thickness of the mucosa.
It is classified as:
In this condition dysplasia affects only the basal layer up to about 1/3 of the mucosa.
When dysplastic changes extends up to 2/3 of the mucosa then it is branded as moderate.
When dysplastic changes involves the full thickness of esophagus it is considered to be severe in nature.
Esophagitis and mucosal atrophy have been reported to be associated with esophageal cancer.
Squamous dysplasia endoscopic appearance:
Squamous dysplasia and early cancers are characterized by a number of morphological changes that can be observed during endoscopy which include:
Mucosal friability, focal reddish areas, erosions, plaques and nodules. In Barrett's esophagus with dysplasia these endoscopic changes are not visible.
Squamous cell carcinoma esophagus general features:
These tumors are well advanced on presentation itself. They may have varied appearances which include, long annular structures, exophytic fungating ulcers
withe raised everted edges, infiltrating below the adjacent mucosa. Nearly 15% of these patients have multiple level tumors.
Classically these tumors show marked submucosal extension with involvement of submucosal lymphatics.
Microscopically, these lesions appear as well differentiated tumors with squamous pearl formation, individual cell keratinization, to nests of poorly differentiated
tumors with poorly cohesive cells often present within a desmoplastic stroma.
There may be a number of variants of squamous cell carcinoma like verrucous carcinoma, spindle cell carcinoma, adenoid cystic carcinoma,
mucoepidermoid carcinoma and small cell carcinoma.
Tumor spread & prognosis:
Esophageal carcinoma in general has a very poor prognosis. In symptomatic patients the 5 year survival rate is less than 5%. Currently the introduction of cispatin in the therapeutic regimen has ensured somewhat prolonged remission. Major problem with this type of malignancy is that 50% of these tumors are operable and out of these only 10% can be resected completely. These patients have widespread lymphatic dissemination with celiac node metastasis.
Important prognostic feature in these patients is the depth of infiltration through the esophageal wall, presence of nodal metastasis, and the size of the tumor. Tumors limited to submucosa have a 5 year survival rate or more than 60%. Intraluminal polypoidal or pedunculated tumors and verrucous carcinoma are most likely to be in this group.
In this condition there is epithelial metaplasia of esophageal mucosa, characterised by a columnar lining, usually accompanied by underlying mucous glands replacing the
normal columnar epithelium of the esophagus for varying lengths begining from the
lower esophageal sphincter upwards. This type of picture invariably follows prolonged gastroesophgeal reflux.
This disorder carries with it an increased risk of adenocarcinoma.
The diagnosis of Barrett's esophagus is commonly made between ages 40-60. There is a very clear male predominance. Patients with this condition exhibit no unique clinical features beyond that of gastroesophageal reflux. These patients should undergo periodical esophagoscopy examination and biopsy to watch out for development of adenocarcinoma.
Primary adenocarcinoma of esophagus is a relatively uncommon tumor. Majority of these lesions arise as a sequelae to Barrett's esophagus. Males predominate. These patients usually give history of reflux, dysphagia and odynophagia. These lesions are better managed by surgical resection and anastomosis.
surgery could be followed by a course of irradiation and chemotherapy.