Brief Answer:
Normal neck feature of adult man.Exclude thyroid problem..

Detailed Answer:
Hi Fanch 87,
Thanks for the query, I have read your query & also seen the images sent. The swelling in the image appears to be in upper part of throat, above the site of thyroid gland.
* Mostly it is a normal feature of human neck.. a laryngeal prominence in between the notch of thyroid cartilage.It can be seen as a bump under the skin of neck which varies from person to person.which can be felt/ moved also.
It's also commonly called as Adam's apple.because of it's appearance in male at puberty.It's responsible for deepening of male voice at puberty& is supposed to be secondary sex character in adult male.
It is without any symptoms except probably some pain if moved side to side.
* The other possibility( though does not appear to be from photograph ).. is thyroid swelling.
IN case you have sluggish actions/ weight gain/ chills / hair loss OR irritated, sweaty, anxious attitude..the thyroid may be at fault. In such case thyroid function tests are indicated . These diagnose / exclude thyroid problem .. which the can be corrected with an endocrinologist's advice.
* I would advise a general check up by your family physician. He may advise thyroid function test to confirm/ exclude thyroid problem .
- He may refer you to endocrinologist if necessary.for specific treatments. .
- Normal thyroid function tests confirms your problem to be not a problem in real sense.. but a sign of your adult hood... so don't worry. Have nutritive food/ good exercise/ sufficient sleep /work hard to achieve your goals & enjoy your life wish you all the best!
I hope you found the answer to be both useful & informative.Any follow up query is welcome.
Please don't forget to grade the answer before you close it.
Thank you.

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Brief Answer:
Investigations/ expert advise are advised.

Detailed Answer:
Hi Fanch 87,
Thank you for the prompt information.
So you have the ball like swelling under your jaw seems to be in mid line.
There are many conditions which can cause such type of problem, but considering absent signs of inflammation on the swelling.( pain, redness, fever ).. as you have not mentioned any.. I feel in your case possible causes would be-
- Miatal( central ) sub mandibular lymph gland enlargement .. ( due to possible infection in it's drainage area in teeth, mouth & floor of mouth.- need treatment of cause.
-Sub mandibular salivary gland problem.
-Dermoid cyst..These are developmental mid line cysts , which grow very slowly -.
- Thyroglossal cyst.. formed from remnants of developmental thyroglossal cells -
- Cystic hygroma--Formed by lymphatic tissue forming cystic spaces -
.
* So out of these, sub mandibular lymph gland & salivary gland problems need to be treated medically.
*Dermoid cyst,Thyroglossal cyst,Cystic hygroma are developmental problems.. usually noted in later life. These are not of any use to body,Do not cause problems except when big in size ( pressure symptoms/ cosmetic value ) so are removed surgically after histo pathological confirmation.
IN this context, I would suggest consultation of a dental surgeon/ oral surgeon . After local examination he may advise X ray/ histo pathological test to confirm diagnosis & specific treatment would follow.
Please don't worry, proper diagnosis & expert advise / treatment would help you.
Hope, this satisfies you. any follow up query is welcome.
Thanks.

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