Terminologia Histologica 10 years on: some disputable terms in need of discussion and recent developments
Abstract
At first sight, the issue of morphological terminology may seem as "closed and changeless chapter", as many of the structures within the human body have been known for decades or even centuries. However, the exact opposite is true.
The initial knowledge of the microscopic structure of the human body has been continuously broadening thanks to the development of new specialized staining techniques, discovery of the electron microscope, or later application of histochemical and immunohistochemical methods into routine tissue examination. Contrary to popular belief, histology has a status of constantly developing scientific discipline, with continuous influx of new knowledge, resulting in an unavoidable necessity to revise the histological nomenclature at regular intervals.
The team of experts of the Federative International Programme on Anatomical Terminology, a working group of the International Federation of Associations of Anatomists, published in 2008 the First Edition of Terminologia Histologica. Terminologia Histologica (TH) is the best and most extensive of all the histological nomenclatures ever issued, however several terms of important histological structures are missing and on the other side, other disputable terms are present.
In this article we have summarized some clinically important, but forgotten cells and tissue structure in TH (e.g., telocytes, myoid cells, laryngeal space of Reinke, lymphatic lacunae of tubal mucosa, or epicardial adipose tissue). The second part of this article is focused on those new terms listed in the current edition of the TH, which are not mentioned in current textbooks of histology (e.g., fusocellular connective tissue, bundle bone as the third type of bone tissue, spongy layer of vagina or arteria vaginata from the splenic white pulp).
Without proper definition and examples of their occurrence, they will be used neither in histological practice nor in human histology teaching. We hope that a wide scientific discussion will develop before the publication of the second edition, so perhaps the mentioned minor flaws will be corrected, and the new edition of the Terminologia Histologica will truly become an internationally accepted communication tool for all histologists.