Thanks for your question on HCM. By your history and description, possibility of lipoma is more likely. Lipoma is the most common benign skin tumour. It is having fatty tissue in it. It is usually single and stable in size. But can sometimes enlarged and becomes painful due to infection. It can also cause restriction in joint movements due to enlargement. So better to consult doctor and get done clinical examination of swelling and ultrasound examination for the diagnosis of lipoma. Usually no treatment is required for it but if it is painful, increasing in size or restricting hip movements then surgical removal is needed.