Epidermoid heteroplasia (heterologous epidermoid differentiation) of basal cells of endometrium versus squamous-cell metaplasia: With the report of a case of cholesteometra

Abstract

The case reported in this paper represents a gradual progressive replacement of surface epithelium, and the epithelial lining of the glands of the endometrium, by stratified squamous epithelium with ultimate loss of all typical histological constituents of the endometrium, the stroma and the epithelium.The process of epidermoid heteroplasia of endometrium, which we think is a proper name for the heteroplastic differentiation of basal epithelial cells of the surface epithelium and epithelial lining of the glands of the endometrium, was observed by us through a period of five years.It was finally complicated by cholesteometra, which we believe is a more proper designation for the distention of the cavity of the uterus by lamellated strips of cornified epithelial cells and sebum-like material than cholesteatoma (Kaufman).While it is possible that in the final phase of the process of epidermoid heteroplasia (epidermization) of the endometrium of the corpus uteri, the inflammation could be an important contributory factor, we are by no means certain about the actual course of events. Whether the inflammation destroys the endometrium and, in the process of ensuring regeneration, the forces which were harbored in the basal cells of the endometrium find an outlet leading to heteroplastic development of the epithelium, or whether the inflammation itself, after the destruction of the normal endometrium, actually stimulates the development of stratified squamous epithelium from basal cells, we could not decide with certainty.The experiment of Zondek, mentioned in the discussion of literature, permits as assumption that certain agents, even if primarily of a specific trophic nature, as estrogens are in case of endometrium, may lead, if applied in unusually large doses, to actual destruction of the target tissue.Because of the environmental change produced by the administration of massive doses of the above-mentioned agent, and the destruction of the original tissue, the normal constituents of the latter are inhibited in their regenerative properties, and the regeneration of tissue follows heterologous patterns resulting, as for instance in our case, in formation of stratified squamous epithelium instead of the ordinary columnar epithelium.The process of replacement of the columnar epithelium of the endometrium (surface epithelium and epithelial lining of the glands) by stratified squamous epithelium as observed in our case follows in general the morphologic patterns which were established by Meyer for the process of epidermization of cervical erosion.This process of replacement of one type of epithelium by another does not have to be identified with process of metaplasia.The development of stratified squamous epithelium in lieu of the endometrium (glands and stroma) in our case, presents only another example of heteroplastic differentiation of the basal cells of this region.The associated heteroplastic differentiation of stroma we consider as particularly essential for the above-mentioned heterologous differentiation of the epithelium.The abandoning of the concept of metaplasia and the acceptance instead of the concept of heterologous differentiation of the basal cells of the uterine epithelium (surface epithelium and the epithelial lining of the endometrial glands) has a purpose of immeasurable diagnostic significance because it lifts the mystery which has always enveloped the process of metaplasia and substitutes the latter with a rational step-by-step descriptive explanation of histological events.The exact understanding of the process brought by descriptive explanation reduces the possibilities of diagnostic deception which could take place in the interpretation of confusing epithelial patterns arising in the process of heterologous differentiation of basal cells of the uterine epithelium.The process of epidermoid differentiation of basal cells of uterine epithelium is gradual.Because it goes through the stage of initial incomplete differentiation, which is deceivingly similar to the state of inadequate differentiation of epithelium (anaplasia), usually associated with clinical malignancy, it could be easily mistaken for an early carcinoma (cardinoma in situ).Therefore, particularly, the exact understanding of the process of epidermoid heteroplasia of basal cells and the exact knowledge of all resulting and associated complicated epithelial pattern are essential to avoid such diagnostic error.The case reported in this paper illustrates different phases of the process of epidermoid heteroplasia of basal cells of uterine epithelium, including the initial stage of incomplete differentiation of stratified epithelium, which could have been easily mistaken for begining carcinoma.The prosoplastic (beyond the normal) differentiation of stratified squamous epithelium, which was observed at the end of the process (five years after the initial observation), may serve as another evidence that the anaplastic appearance recorded in the initial observation was only a transitory phase of differentiation of epithelium (which went beyond the normal mark), and not a beginning of a state of progressive anaplasia, associated with carcinoma.