Final answer:
A tumor of the nail bed is called an onychoma. This condition is different from melanoma, which is a type of skin cancer that can also affect nails but originates from melanocytes. The nail bed is a specialized structure that supports nail growth from the matrix and consists of packed keratinocytes.
Step-by-step explanation:
A tumor arising from the nail bed is referred to as an onychoma. This term specifically targets tumors that originate from the nail bed, which is the portion of the finger or toe over which the nail plate exists. The nail bed itself is a specialized structure of the epidermis that is found at the tips of our extremities, such as fingers and toes. The nail plate is composed predominantly of keratin, a protein that provides strength and rigidity to the nails. Paronychia is an infection of the nail fold, including the tissue bordering the nail. Melanoma is a type of cancer that affects melanocytes, the pigment-producing cells, and can also develop under the nail but differs from an onychoma. Meanwhile, onychocyst refers to a cystic formation about the nail. When it comes to nail growth, nails grow out from the nail matrix, which is at the proximal end of the nail, and the hyponychium is the area beneath the free edge of the nail, furthest from the cuticle.