Arias-Stella reaction, also Arias-Stella phenomenon, is a benign

Benign

A benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...

 change in the endometrium

Endometrium

-Function:The endometrium is the innermost glandular layer and functions as a lining for the uterus, preventing adhesions between the opposed walls of the myometrium, thereby maintaining the patency of the uterine cavity. During the menstrual cycle or estrous cycle, the endometrium grows to a...

 associated with the presence of chorionic tissue

Chorionic villi

Chorionic villi are villi that sprout from the chorion in order to give a maximum area of contact with the maternal blood.Embryonic blood is carried to the villi by the branches of the umbilical arteries, and after circulating through the capillaries of the villi, is returned to the embryo by the...

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Cytologically

Cytopathology

Cytopathology is a branch of pathology that studies and diagnoses diseases on the cellular level. The discipline was founded by Rudolf Virchow in 1858. A common application of cytopathology is the Pap smear, used as a screening tool, to detect precancerous cervical lesions and prevent cervical...

, it looks like a malignancy and, historically, it was diagnosed as endometrial cancer

Endometrial cancer

Endometrial cancer refers to several types of malignancies that arise from the endometrium, or lining, of the uterus. Endometrial cancers are the most common gynecologic cancers in the United States, with over 35,000 women diagnosed each year. The incidence is on a slow rise secondary to the...

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Significance

It is significant only because it can be misdiagnosed as a cancer

Cancer

Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

. It may be seen in a completely normal pregnancy

Pregnancy

Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...

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Diagnosis

It is characterized by nuclear

Cell nucleus

In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...

 enlargement and may also have any of the following: an irregular nuclear membrane, granular chromatin

Chromatin

Chromatin is the combination of DNA and proteins that make up the contents of the nucleus of a cell. The primary functions of chromatin are; to package DNA into a smaller volume to fit in the cell, to strengthen the DNA to allow mitosis and meiosis and prevent DNA damage, and to control gene...

, centronuclear vacuolization, and pseudonuclear inclusions.

Five subtypes are recognized:

1. Minimal atypia.
2. Early secretory pattern.
3. Secretory or hypersecretory pattern.
4. Regenerative, proliferative or nonsecretory pattern.
5. Monstrous cell pattern.

History

It was first described by Javier Arias Stella

Javier Arias Stella

Javier Arias Stella is a Peruvian pathologist who discovered the "Arias-Stella's phenomenon" , which is named after him.-Education:...

, a Peruvian pathologist in 1954.