An omphalolith or umbolith or omphalith or navel stone or umbilical concretion is a periumbilical mass that may form due to the accumulation of

sebum A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest nu ...

and

keratin Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up scales, hair, nails, feathers, ho ...

. The colour is black or brown, and may be related to the skin type of the patient. It may resemble a

malignant melanoma Melanoma, also redundantly known as malignant melanoma, is a type of skin cancer that develops from the Biological pigment, pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, i ...

. It may be caused by poor hygiene, and may form in retracted navels in obese people.

Etymology

The name was derived from the Greek words ''omphalos'' ( el, ομφαλός), meaning

navel The navel (clinically known as the umbilicus, commonly known as the belly button or tummy button) is a protruding, flat, or hollowed area on the abdomen at the attachment site of the umbilical cord. All placental mammals have a navel, although ...

, and ''lithos'' ( el, λίθος), meaning stone.

References

{{medicine-stub Diseases and disorders Nephrology