The Arias-Stella Reaction:

Facts and Fancies Four Decades After

change associated with chorionic tissue effect has been widely confirmed in the

literature. However, errors and inaccuracies in text books and other publications often

occur. This review clarifies some of these misconceptions and presents a summary of

new data on the histologic and immunohistochemical characteristics of the change. A

brief discussion of the pathogenesis and biologic significance of the alteration is

included. Key Words: Arias-Stella Reaction—Atypical endometrium—Endometrial

change

change

Forty-six years ago, I bravely knocked on the door of

Dr. Fred W. Stewart’s office. He was Chairman of the

Pathology Department of Memorial Hospital for Cancer

in New York City. I had been a fellow in pathology for

2 months and finally I was reaching my main goal at this

famous hospital: to consult with the pathologist then considered

one of the foremost in tumor diagnosis in the

United States on two cases that I had seen while a medical

student back home in Perú and that had been diagnosed

by my seniors as forms of early endometrial cancer.

However, given the uniqueness of the changes, and

because one case was associated with an intramural

chorioadenoma destruens and the other with an ectopic

pregnancy, I thought that this was some form of endometrial

reaction resulting from the chorionic hormonal

stimulation.

I expected that Dr. Stewart would send me to the bibliographic

references, which I had searched in vain for

more than 2 years. His answer left me dumbfounded: “I

don’t know! Javier—you have something to study.” The

rest of the story is not for this occasion, but I have recreated

the background, development, and immediate

corollary in the form of a story for medical students,

which will soon be published (1).

The initial publication appeared in the Archives of Pathology

in 1954 (2) and it is interesting today to recall the

very first reaction in the literature. Dr. Emil Novak, the

author of the textbook Gynecological and Obstetric Pathology,

which, during my youth was considered to be

which, during my youth was considered to be

the Bible, was among other things the editor of the Survey

of Obstetrics and Gynecology. He made the following

comments when my article was published (1,3):

comments when my article was published (1,3):

“This is an interesting study, but one upon which it

would be difficult to comment unless one had made

similar studies, which no one appears to have

done. . .”

“While I have examined many thousands of endometria

including many containing trophoblastic rest, after

miscarriage hydatidiform mole, chorioadenoma destruens,

or choriocarcinoma, I cannot say that I have

noted the particular cellular changes which Arias-

Stella has described.”

“To show how foolish an objection this last statement is,

I may say also that I examined many ovaries before

1921, and that not a few of them showed endometrium,

but I did not appreciate the importance and the

frequency of endometriosis until after Sampson’s first

publication in 1921, nor did anyone else.”

Address correspondence and reprint requests to Javier Arias Stella,

M.D., Instituto de Patología y Biología Molecular Arias Stella,

Gregorio Escobedo 612, Jesús María, Lima, Perú. E-mail: aspath@

tsi.com.pe.