Normal Anatomy of Esophagus-

Esophagus is a muscular  tube  between 6th vertebral body (cricopharyngeus) and  10th -12th thoracic vertebra ( just below the diaphragm ). It measures 25 - 30cms in adults. 

Esophagus is divided into  3 parts -
i) cervical ( 5cm )- lies behind the trachea ,

ii) thoracic (20cms)- extends from the thoracic inlet  into the posterior mediatinum and 

iii) abdominal (1 - 3cms)- starts where esophagus passes through the diaphramatic hernia.

3 esophageal constrictions-

i) Uppermost - caused by cricopharyngeal muscle 

ii) Middle -  where esophagus is crossed by aortic arch at tracheal bifurcation.

iii) Lowermost  - caused by gastroesophageal sphincter  at the esophageal hiatus of the diaphragm

Esophageal Resection Specimen:

                    

Usually consists  of an esophago-gastrectomy specimen.  Resection is usually carried out to remove malignant tumour of the esophagus and gastric cardia, as a primary treatment or after radiotherapy or chemotherapy.

Esophagectomy is also indicated in patients with extensive high grade dysplasia in Barrett's esophagus, undilatable strictures and sometimes in benign obstructing tumours.

Fresh specimens should be carefully examined, and the outer (circumferential) resection margin painted with Indian ink or other marking dye. This is important for the assessment of completeness of excision and measurement of distance of tumour from the circumferential resection margin. The specimen should then be opened longitudinally, pinned to a cork board, and fixed by immersion in a fixative (usually buffered 10% formalin or 10% formol saline) for 48–72 hours to ensure adequate fixation and facilitate obtaining thin slices. It should be noted that after resection the oesophagus undergoes shrinkage, which affects the upper more than the lower margin, with tumour tissue changing little in length. Even if the oesophagus is immediately pinned and fixed after resection it shrinks by more than 10%, and if pinning and fixation are delayed it shrinks by more than 50%, which accounts for the discrepancy between surgeons' and histopathologists' measurements.

After fixation, it is advisable to have a photograph or diagrammatic representation of the specimen made to illustrate pathological findings and indicate sites of blocks selected for histological examination.

Macroscopic examination of esophageal resection specimen :

1. Specimen measurement (pinned and unpinned)-  In addition to the total length, specify individual lengths of the esophagus and stomach .  

2. Tumour  measurement (length and width)

3. Tumour type - Polypoid ( favourable prognosis) and others (ulcerated & excavating).

4. Distance of the tumour from the nearest distal and proximal margins.

The following informations should be included in the report :

- Tissues included in the biopsy- Presence of gastric epithelium must be mentioned.

- Tumour type- Adenocarcinoma , squamous cell carcinoma, small cell carcinoma etc.

- Tumour differentiation- well, moderate, poor

- Depth of invasion - TNM system

-Serosal involvement - For tumours involving proximal stomach.

-Distance of tumour from the proximal and distal margins- If the distance is less than 1mm the margin is considered to be involved. Mention whether the margins show any evidence of Barrett's metaplasia or dysplasia

-Circumferential margin

-Vascular invasion

-Perineural invasion

-Lymph node - Number of lymphnodes present and the number involved by metastatic tumour.

-Barrett's metaplasia adjacent to the tumour.

NOTE: 

Normally gastro-esophageal junction can be easily identified on the mucosal surface IMAGE(WebPath). However,  this can be difficult in case of  extensive Barrett's esophagus and when a large  tumour IMAGE(WebPath) obliterates the squamocolumnar junction IMAGE . In these conditions the junction can be identified by the peritoneal extension on the serosal surface.
The pathologist has to decide whether the tumour is of esophageal or gastric origin.
When more than half the tumour is present above the gastro-esophageal junction the tumour is  regarded as  esophageal  carcinoma.

               

Survival rate in esophageal carcinoma:

The most important prognostic indicators of esophageal carcinoma are :

1. Depth of tumour invasion.
2. Involvement of lymph nodes.

Overall 5 year survival in early stage carcinoma is about 57%-78%.
5 year survival in advanced stage carcinoma with lymph node metastasis, is 10% or less.

Prognosis of patients without lymph node metastasis of esophageal carcinoma is generally good.
Despite high survival rate at 5 years , local recurrences and distal metastasis may still occur.
Prevention and therapeutic intervention at an early stage is necessary to alter the natural evolution of the disease

When the tumour is confined to the wall of the esophagus 5 year survival is approximately 40%.
When the tumour invades the adventitia the 5 year survival  drops to 4%.
Distant metastasis to abdominal lymph nodes, liver and lung occur in 18% cases.

2/3rd of patients have a recurrence within one year and nearly all within 2 years after primary operation.
In 1/3rd to half the patients the recurrent tumour is located to the previous operation site.  Rest of the recurrences are distant metastases.
 

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