Very few students and teachers of histopatholgy understands the history of this medical specialization. A clear cut understanding of history and evolution is vital for the individual's confidence and upkeep of the profession. We can only build on any concept when the history and evolutionary trend are well understood.
The specialty of histopathology tecnique could be traced to the works of Johannes Muller in 1838. This followed the construction of the first compound microscope in 1591. The development of the simple microscope was credited to Anton van Leeuwenhoek who started the devolopment of simple microscopes with single lenses. This occured in 1673.
Microtome for sectioning animal tissues was first constructed in 1848. In mid 1800s, paraffin wax for infiltration and embedding was introduced. Formalin, widely used for fixation today was first used in 1893.
In 1945, automated tissue processors replaced hand processing while cryostats were first manufactured in 1951. During the last 50 years, enzyme histochemistry, electron mocroscopy and polarizing microscopy have all become diagnostic tools in histopathology.
In the 1980's, the widespread use of immunohistochemistry revolutionized cancer diagnosis and it is still evolving.
What other development of histopathology techniques occured in the United States and United Kingdom from the historical sense? These are the issues presented by Michael Titford in 'A Short History Of Histopathology Technique'.
Within the last 30 years, histotechnologists have seen the introduction of microcomputer-controlled tissue processors, immunohistochemistry (IHC), in situ hybridization.
22 Histopathology Technical Categories And Historical Background
Histopathology like any other specialization developed over time. How it happened is explained under 22 technical categories as follows:
1. Microscope Development: As far back as 1591, Zacharias Jansen made the first compound microscope in collaboration with his father in Holand. These microscopes suffered from spherical and chromatic aberration, low magnification and limited to reflected light. Anton van Leeuwenhoek made simple microscopes with better resolution in 1673 though rudimentary to today’s standard. In those days, researchers were more interested in the microscopes that the specimen. In 1827, Joseph Lister corrected the spherical and chromatic aberrations observed in early microscopes and together with Thomas Hodgkin for the first time published descriptions of smooth and skeletal muscle and the lack of a nucleus in human red blood cells. Their effort was the tonic needed for the commercial production of microscopes starting in Germany, France and Italy. The use of the microscope was further facilitated by the works of Amici and Chevalier who developed the achromatic lens for color correction in the 1830s. By the late 1870s, Ernst Abbe had further advanced the science of microscopy with the development of apochromatic lens, substage condenser to gather light and immersion lenses. The modern binocular microscope was developed in 1902.
2. Fixatives: Early researchers had made effort to harden biological specimens for thin sections to be cut. Heat fixation was employed then by Malpighi. Later, others used chemical agents such as alcohol, acetic acid, chromium trioxide and potassium dichromate to preserve tissues. Following this was the use of compound fixatives. Muller’s fluid in 1860, Zenker’s in 1894 and Carnoy’s in 1887. Formalin, the now most popular fixative was discovered by Blum in 1893.
3. Microtome Development: Hill in 1770 introduced the first hand microtome to cut sections of twig. Early microtomes were meant for plant tissues and were called ‘cutting engines’. Not until 1848 did the use of microtome for animal tissues began. The Cambridge rocker was developed in 1885 by Horace Darwin and the sledge developed by Jung in 1910. Over the years, microtomes have improved though the basic design remains the same. Motorized microtomes are the modern machines made to reduce the carpal tunnel syndrome caused by repetitive motion.
4. Embedding Media: Paraffin wax is the most popular medium for embedding. It was developed over a period of time by several researchers. Its discovery has been variously attributed to Klebs-1869, Born & Sickler –1871, Giesbrecht-1881 and Butshili-1881.
5. Histopathology As A Field: Francois Bichat of France(1771-1802) was aptly described as the ‘Father of Histology’. The specialty of Pathology first came into fruition in Germany in the 1800s. Johannes Muller can be called the ‘Father of Histopathology’. He was credited for attracting gifted students such as Rudolph Virchow, Jacob Henle, Karl Reichert, Karl Kuppfer and others who made contributions to histology in the late 1800s. Rudolf Virchow(1821-1902) was the most influential pathologist of all times. In England, the Royal Microscopical Society was formed in 1839. In 1848 John Quekett was the first to decalcify tissue. In 1845, Hermann Lebert reported that the microscope could be used to differentiate malignant and benign tissue by examining the cellular morphology.
6. Development of Staining: Carmine and Saffron were the early dyes used in the field of microscopy. Haematoxylin was reportedly first used successfully by Wilhelm von Waldeyer in 1863. William Perkin prepared the first synthetic dye from aniline in 1856. Basic fuchsine was first manufactured in in 1865 and aniline blue in 1868. Schwarz devised the first double stain in 1867. Differentiation was first used in 1868. Haematoxylin solutions were later developed in rapid succession. Delafield’s –1885, Ehrlich’s –1886, and Heidenhain’s-1892. The H&E method was developed in 1875 by Wissowzky. Ziel Nelson Acid fast stain was developed in 1883, Gram stain appeared in 1884, Congo red in 1886 and the fat stain Sudan III in 1896. Mallory’s phosphotungsti acid hematoxylin was introduced in 1897. The Giemsa stain appeared in 1902, PAS in 1946 by MacManus and the alcian blue method of Steedman in 1950.Silver stains also need being mentioned. The original von Kossa method in 1901, Masson method for argentaffin in 1914 with Fontana’s modification in 1925. Bielschowsky’s method for axon and neurofibrils-1904 etc
7. Automatic Stainers: In the United kingdom, Shandon Company introduced their first automated stainer in 1965. In the United States, The Stainomatic manufactured in the 1970s by Gam Rad Incorporated was widely used. In the late 1990s special multiple, simultaneous stainers were introduced such as the Artisan from CytoLogix.
8. Frozen Sections: Francois Raspail(1794-1878) was regarded as the ‘Founder of Histochemistry’ and to have used frozen sections, Stilling in 1842 was reputed to be the first person to use frozen sections. Welch was the first to use a frozen section to diagnose breast cancer in 1891. Commercial production of cryostats began in the United Kingdom in 1951 by Bright Instrument Company. Pearse was the fist professor of enzyme histochemistry in the University of London.
9. Tissue Processors: The first automated tissue processor was made in Germany in 1909. In 1945, Edwin Weiskopf, founder of the Technicon Corporation commercially produced popular tissue processor in the United States. In the U.K., Shandon began manufacture of its tissue processor in 1951. In 1979, two companies started marketing fluid transfer tissue processors and the Tissue Tek processor. In 2004 a throughput tissue processor was marketed.
10. Development of Other Histology Procedures: In the 1950s, paraffin waxes of different melting points were made available to facilitate sectioning. In the 1960s, plastic polymers were added to control hardness and improve sectioning. Cooling the blocks further hardens the wax and improves sectioning.
11. Slides, Coverslips and Mountants: In 1839, the 1 inch by 3 slides was adopted by the Microscopical Society of London which became the global standard. In 1840, the glass coverslip was developed by the Chance Glass Company of Birmingham, England. In 1985, the automatic glass coverslipper was introduced by Hacker Instruments.. Canada Balsam was the early mountant used in histopathology. It as first used in 1835. Synthetic mountants became popular in 1960s.
12. Other Laboratory Ware and Consumables:The Coplin jar was invented by W.M. Coplin in 1897. Early Histotecnologists used paper molds for embedding or Leuchart’s type molds. It is still in use in most laboratories of developing countries. Paraffin blocks were then mounted onto wooden blocks or a microtome stage for sectioning. Floating Bath was introduced by Gaskell in 1890. Embedding Rings were introduced by Dr. James B. McCormick in 1958. The cassettes system also invented by Dr. McCormick was introduced in 1968. Color Code cassettes were introduced in the 1980s. In 1978, the disposable microtome blades were introduced by the Feather Company. This eliminated the use of steel knives which required frequent honing and stropping.
13. Alternative Embedding Media: Celloidin was first used in 1877. Ester wax was developed in 1947 by Steedman and recommended for hard tissues, incests and cortical bone.
14. Plastic Sections: In the mid 1980s, Glycol Methacrylate (GMA) embedding was introduced for the production of thin biopsy sections. It is however, limited to academic and research environments
15. Enzyme Histochemistry: Gomori and Takamatsu developed methods for demonstrating alkaline phosphatase in frozen sections in 1939. Enzyme histochemistry is now largely limited to diagnosing muscle biopsies such as neuromuscular disorders, acetylcholinesterase in Hirschsprung’s disease, some enzyme deficiency disorders and other uncommon uses.
16. Electron Microscopy: Ernst Ruska developed the first EM in the late 1920s. Siemens built the first commercial electron microscope in 1939. Although found primarily in medical centers and university settings, electron microscopy came into use in the late 1950s and early 1960s. By the 1970s, they became widely spread.
17. Polarizing Microscopy: No clear details about how it was introduced into clinical laboratories though has wide applications. It is most useful in viewing birefringent materials such as collagen fibres, bone, striated muscle, hair and cholesterol and amyloid deposits.
18. Fluorescence Microscopy: This technique was developed by Coons, Creech and Jones in 1941. Though expensive, it is useful in the auramine rhodamine method for acid fast bacilli.
19. Immunohistochemistry(IHC): Researchers first used DAB-3,-3 diaminobenzidine to create a stable colored compound at the site of protein in the tissue. In 1970, Sternberger etal developed the peroxidase antiperoxidase method (PAP). In 1974, Taylor and Burns developed IHC method for formalin-fixed, paraffin-embedded tissues. IHC became available to routine histopathology laboratories in the U.S. in the early 1980s.
20. Laboratory Information Systems(LIS): Arrived in clinical laboratories starting from mid 1970s. Workable packages for pathology laboratories came up later.
21. Books And Literature: Arthur Bolles Lee published ‘The Microtomist’s Vad-Mecum in 1885. Mallory And Wright Published ‘Pathological Techniques’ in 1901. Harry Carlton published ‘Histopathological Techniques in 1926. Culling published Handbook of Histopathological Techniques in 1957. Pearse published Histochemistry-Theoretical and Applied in 1953. In 1980, Dezna Sheehan and Barbara Hrapchak published Theory and Practice of Histotechnology. More recently, John Kiernan’s Histological and Histochemical Methods-Theory and Practice published in 1981 with recent updates.
22. Present State Of Histopathology Technique: Less harzadous fixatives and newer IHC methods now take front stage. Microwave processors are now used for processing and staining in some laboratories. New instruments such as Sakura Finetek Xpress processes thin slices of tissue rapidly using proprietary chemicals. The use of tissue microarrays for gene expression profiling gaining increased interest.
Michael Titford: A Short History Of Histopathology Technique: The Journal of Histotechnology/vol.29, No 2./June 2006 pg 99-110