An incidental oesophageal finding

This was an incidental finding in the mid-oesophagus. Subsequently an EUS is organised and the lesion is ultimately removed (histology in the last image)
WHAT IS THE DIAGNOSIS?

■ Neuroendocrine tumour

I've never actually seen an oesophageal NET

■ Granular cell tumour

But it isn't a small white submucosal disc?!

■ Leiomyoma

A shrewd guess!

■ GIST

These are VERY rare in the oesophagus (but common in stomach)

■ Melanoma

Usually look brownish endoscopically!

explanation

Leiomyomas are the most common submucosal lesion found in the oesophagus. No idea why they are so rare in the stomach, where GIST's are the most common submucosal lesion. Correspondingly GIST's are very rare in the oesophagus.

These usually arise from the circular muscle propria layer. On CT they are often calcified and there are of course no nearby nodes to suggest malignant disease.  Indeed, malignant transformation is extremely rare and for this reason many centres would ignore a small submucosal lesion such as this, when found in an elderly person. Larger (around 5cm usually) and symptomatic lesions (which are more likely to be leiomyosarcomas) are enucleated surgically. "- They shell out like peas" according to one of our UGI surgeons.

However, our local surgeons are also careful to point out that resection usually result in some damage to the muscle propria layer, which require repair as otherwise a diverticulum may develop.

With endoscopists spending more time in the 'third oesophageal space' (i.e. the submucosal space), doing ESD's and POEM, the suggestion that we should also remove leiomyomas endoscopically has arisen. May seem like a good idea but I would advocate caution for the simple reason that endoscopically, we are unable to repair the defect we cause in the muscle propria layer ... 

Oh, how about that 'SMA stain' used in the histology.  This is 'Smooth Muscle Actin' stain which does exactly what it says on the tin ...