Atypia is a clinical term for abnormality in a cell. The term is medical jargon for an atypical cell.

Atypia: Etymology: Gk, a + typos, without type; a condition of being irregular or nonstandard.

It may or may not be a precancerous indication associated with later malignancy

Malignant

Malignancy is the tendency of a medical condition, especially tumors, to become progressively worse and to potentially result in death. Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis...

, but the level of appropriate concern is highly dependent on the context with which it is diagnosed.

Atypia can be caused by an infection or irritation if diagnosed in a Pap smear

Pap smear

The Papanicolaou test is a screening test used in to detect pre-cancerous and cancerous processes in the endocervical canal of the female reproductive system. Changes can be treated, thus preventing cervical cancer...

, for example. In the uterus

Uterus

The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...

 it is more likely to be precancerous.

The term atypia is also used dermatologically and can be a precursor to melanoma

Melanoma

Melanoma is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the eye...

.

The related concept of dysplasia

Dysplasia

Dysplasia , is a term used in pathology to refer to an abnormality of development. This generally consists of an expansion of immature cells, with a corresponding decrease in the number and location of mature cells. Dysplasia is often indicative of an early neoplastic process...

 refers to an abnormality of development, and includes abnormalities on larger, histopathologic, scales.