Hello,
Thanks for posting your query.
You have noticed a painless lump which is the size of a pea under the skin of your calf.
There are many possible causes for it which include:
• Skin cysts
• Cherryangioma
• Dermatofibromas
• Epidermoid cysts
• Folliculitis
• Keratoacanthoma
• Keratosis pilaris
• Lipomas
• Neurofibromas.

Lumps can be caused by any number of conditions, including infections, inflammation, tumors and trauma. Depending on the cause, lumps may be single or multiple, soft or firm, painful or painless. They may grow rapidly or may not change in size.
Lumps due to infectious causes in or near your leg may appear as boils or abscesses.

There is a probability it might be a Lipoma. Lipoma is a lump or mass that is made up of fat cells (adipocytes). Lipomas are a common, benign (noncancerous) type of slow-growing tumor. They most often develop just under the skin in the subcutaneous tissue, located beneath the skin and above the muscle.

There are rare causes, it could be due to malignant tumors of the skin, soft tissues, or bones can appear as lumps on the thigh. In these cases, either a biopsy or surgical removal of the lump can determine whether cancer is present.
You can self monitor it for any change in size, color, pain or tenderness in which case an immediate medical attention is needed.
Do not worry, it is highly unlikely to be malignant.
Hope this answers your query. I will be glad to answer the follow up queries that you have.
Please accept my answer in case you do not have further queries.
Wishing you good health.
Regards.
Dr. Rakhi Tayal.

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Hello.
Thanks for writing again.
The pea sized lump is not likely to be related to running or any exercise. If there is a sudden increase in its size or it becomes painful and red, the you need to get it examined from your physician. Size of the lump does not matter as long as there is no sudden increase in the size.
Hope my answer is helpful.
Do accept my answer in case there are no further queries.
Regards

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