Available online at www.annclinlabsci.org Annals of Clinical & Laboratory Science, vol. 41, no. 2, 2011 201

A Note from History: Microscopic Contributions of Pioneer Pathologists

Steven I. Hajdu

Keywords: history of pathology, history of medicine, history of science, history of microscopy

The microscope, such an integral part of with the microscope, physicians in the 17th and pathology today, was only reluctantly accepted 18th centuries were occupied with correlating by physicians at the time of its invention clinical and autopsy findings by naked eye in 1590. After the Dutch Zacharias Janssen examinations [5]. Although the term pathology invented the compound microscope by was introduced by the French physician Fernel combining convex lenses in a tube, Holland and (1497-1558) in 1554 [6], there were only Italy became centers for the production and use sporadic suggestions of using the microscope of the new instrument. The name “microscope” for pathologic studies [7,8]. Two of the greatest was first suggested in 1625 by Faber a botanist. autopsy pathologists, the Swiss Boneti (1620- Early users of the microscope in Italy included: 1689) and the Italian Morgagni (1682-1771) Galileo, an astronomer and physicist, Stelluti, never used a microscope. Later on, astute a naturalist, Fontana, an astronomer, Faber, a pathologists such as the French Bichat (1771- botanists, Spallanzani, a biologist, Kirche, a 1802), the English Baillie (1761-1823) and the Jesuit priest, and two physicians, Borelli and Austrian Rokitansky (1804-1878), continued Malpighi [1]. to make their pathologic observations the traditional way, purely by gross examination By the time the classical period of microscopy of diseased organs and tissues [9]. Because began in the 1660s with publications by Hooke good fixative, paraffin embedding , microtome (1635-1703), Leeuwenhoek (1632-1723), and eosin stain were not available prior to the Swammerdam (1637-1680) and de Graff (1641- 1860s, pioneer microscopic pathologists most 1673), it was apparent that the microscope often obtained their specimens for microscopic had opened a new avenue of discovery [2]. examination by scrapping and teasing out the Most of the early microscopists were botanists, cut-surface of tissues or by preparing smears zoologists, naturalists and amateur scientists. from fluids and aspirates. They made and published random microscopic observations without pursuing any specific line Gabriel Andral (1797-1876) of Paris was the of study, such as Hooke’s discovery in 1665 first gross pathologist turned microscopic of the vegetable cell in cork [3]. This seminal pathologist. Midway in his career as a observation had no follow-up until 1838, pathologist, he focused his attention on when Schwann (1810-1882) recognized and microscopic alterations of the blood. In 1843, he published that animals, humans and plants published the first concise treaty on pathological alike consist of cells [4]. hematology and created a new field in medicine – hematology [10]. In his book, Andral referred While early scientists continued their work to an increased number of globules (white blood cells) in the blood as leukocytosis and observed that excess increase of globules was Address correspondence and reprint requests to Steven I. Hajdu, M.D., 1759 Drumcliff Court, Westlake Village, California 91361- associated with high fever and rapid heartbeat. 1636; tel 805 496 0691; fax 805 496 0620; e-mail [email protected] He noted that anemia was due to a decrease 0091-7370/11/0200-201. © 2011 by the Association of Clinical Scientists, Inc. 202 Annals of Clinical & Laboratory Science, vol. 41, no. 2, 2011 of red globules (red blood cells) in the blood that was named years later as the source of and that anemia could vary from mild to severe chordoma. He identified the paramesonephric depletion of these elements. He also described duct (Mullerian duct) and deduced that lead poisoning, septicemia and polycythemia. vestigial rests of this duct may form tumors thus Another of Andral’s innovations was measuring identifying the source of mixed mesodermal the proportions of blood constituents, such as (Mullerian) tumors of the female pelvic organs. fibrin, globules (cells) and water, in health and He described the histology of radial (Muller) disease. He knew that fibrin could precipitate fibers of the retina and outlined the topography and form solid a structure (thrombus). His of the anterior and posterior spinal nerve roots. examination of blood from patients and from In his book, On the Finer Structure and Form the deceased led him to conclude that there of Morbid Tumors, published in 1838, the existed primary blood diseases [10]. same year his pupil Schwann announced his cell theory, Muller presented the microscopic Shortly after his appointment in 1833 as features of many benign and malignant professor and chairman of pathology at the tumors supporting the cell theory as a basis for University of Berlin, Johannes Muller (1801- comprehension of the nature of cancer [11]. 1858) began collecting tissue samples from He concluded that malignant tumors consisted surgical procedures and postmortem dissections of the growth of abnormal cells. He attributed for microscopic examination with his assistants. cancer to the formation of new cells in diseased Among his laboratory staff were a number organs, with the potential to spread to other of renowned physicians. Theodor Schwann parts of the body by vascular invasion. Muller (1810-1882) in collaboration with the plant associated cancer with aging and identified physiologist Matthias Schleiden (1804-1881) tumor necrosis (apoptosis) as a sign of regression. established the cell theory in 1838 [4]. Schwann He distinguished microscopically epithelial and also identified the perineural cells which are connective tissue tumors. He divided carcinomas named after him. Jacob Henle (1809-1885), into carcinoma simplex (squamous carcinoma), known for his microscopic classification of carcinoma alveolare (adenocarcinoma), tissues, described the loop of Henle in the carcinoma medullare, carcinoma fasciculatum kidney and introduced the term epithelium in (spindle cell carcinoma), carcinoma reticulare, 1857. Robert Remak (1815-1865) introduced and carcinoma melanodes (pigmented the three layer concept – ectoderm, mesoderm melanoma). As to connective tissue tumors, he and endoderm – and in 1852, was the first described myxoid and fibrous lipomas, fibroma, to point out that growth of tissues was infiltrating fibrous tumor (desmoid tumor), accomplished by division of pre-existing cells. cystosarcoma of the breast, chondroma, Rudolph Kolliker (1817-1905) demonstrated enchondroma, osteoma, chondrosarcoma and the cellular origin of spermatozoa in 1841 and osteosarcoma. Muller’s illustrations are distinct he concluded in 1885 that hereditary characters and the corresponding legends are concise. were transmitted by the cell nucleus. Rudolph He wrote that the examination of numerous Virchow (1821-1902) achieved fame because microscopic preparations of tumors has taught of his innumerable contributions to cellular him that cancers are possessed of certain pathology in the 1840s and 1850s. peculiar microscopic features, which may serve to identify them [11]. Muller’s contributions to Muller equipped his laboratory with the pathology are many but, above all, he should be latest achromatic compound microscopes and remembered as the originator of histopathology expected all his assistants to become skilled and cellular pathology. microscopists. Muller himself carried out numerous embryologic and physiologic studies Julius Vogel (1814-1880), a disciple of before he focused on tumor pathology. He Johannes Muller, published his pioneering book discovered the cellular nature of the notochord Pathological Anatomy of the Human Body in Microscopic Contributions of Pioneer Pathologists 203 1843 in Berlin. Being the first comprehensive tumor of bone). Lebert recognized that there general pathology book containing macroscopic are many different microscopic forms of cancer and microscopic illustrations, it was rapidly and that malignant tumors are distinctly translated from German into English and different microscopically from benign tumors. was published in London and Philadelphia in He described and illustrated enlarged nuclei, 1847 [12]. The book consists of text and 10 macronucleoli, and multiple nuclei as hallmarks plates with over 100 microscopic illustrations. of malignant cells [13]. The legends for figures are comprehensive microscopic descriptions of histologic and He emphasized the importance of examining cytologic details. The bulk of the figures show, every pathologic specimen under the microscope for the first time, microscopic features of specific but warned that microscopic examination was pathologic lesions. Among the illustrations time consuming and every observer his own are cytologic preparations of sputum and teacher. Undoubtedly, Lebert was not only a pleural and pericardial effusions of patients microscopic pathologist par excellence, but he with bronchitis, tracheitis and pneumonia. In also published the first microscopic pathology addition to illustrations of various concretions atlas, which served as the basis on which and crystals there are histologic sections of others, including Rudolph Virchow, built their granulomas, gangrene, hyperplastic lymph concepts about the histology of pathologic nodes, cirrhotic and fatty liver, polypoid and lesions. papillary tumors of the uterus and bladder, and carcinomas of the breast, lung, cervix, liver and Rudolph Virchow (1821-1902) was Johannes testis. It is of particular interest that one of the Muller’s assistant in the late 1840s in Berlin, plates is almost entirely devoted to microscopic and was the primary autopsy pathologist of illustrations of what appear to be hepatoma and his department. A few years after Muller’s seminoma [12]. retirement, Virchow was appointed his successor in 1855. Virchow’s contribution to pathology Hermann Lebert (1813-1878) was Professor of began with the founding of his own journal in Pathology in Paris and Zurich. 1847 as the Archiv fur pathologische Anatomie His Pathologic Physiology published in 1845, and Physiologie. The Archiv is recognized as consists of text in 2 volumes and an atlas with the first periodical devoted to pathology and 22 page-size plates with over 200 figures and 33 has remained one of the leading journals of pages of legends for figures [13]. Inflammatory pathological anatomy to the present time [14]. and other reactive lesions and benign and malignant tumors are described and illustrated, Virchow’s contributions to microscopic as seen on microscopic examination of cells and pathology are too numerous for inclusion in tissue sections. Lebert treated his microscopic this review. His description of white blood preparations with acetic acid, for transparency, cells (leukemia) in an autopsy case in 1845, the and added dilute iodine for color. year in which Hughes Bennett (1812-1875) in England independently described the same A cursory listing of the most pertinent parts disease, was the beginning of his cellular studies of Lebert’s “legends for figures” from my first and led to his microscopic identification of two English translation is presented in Table 1 [13]. types of leukemia, myeloid and lymphoid. As a prosector, he observed that intravascular blood Lebert illustrated solid and gelatinous (colloid) clots (thrombi) may detach from the wall of the cancers of the colon and divided squamous vessel and be carried along in the blood stream cancers into young (epidermoid) and old through the heart into the lungs. He named (keratinizing) forms. He gave the name myeloid the detached fragments emboli. In 1858, tumor to neoplasms that were composed of Virchow published his magnum opus, Cellular marrow-like cells (leukemia and giant cell Pathology [15]. It represents the culmination 204 Annals of Clinical & Laboratory Science, vol. 41, no. 2, 2011

Table 1.

Inflammatory and reactive lesions:

Tuberculous lymphadenitis and granulomas Sputum contaminated with saliva and squamous cells and squames of the buccal mucosa Abscesses of skin, brain and the liver Emphysema Ulcers of the stomach, bronchi and the colon Sebaceous cyst Purulent and non-purulent pleural, peritoneal and pericardial effusions Melanosis coli Acute and chronic pneumonia Fatty and fibrous (cirrhotic) liver Crenated red blood cells Echinococcal cyst in the liver containing the head and scolices of the parasite Anucleated, mononucleated and multinucleated pus cells (white blood cells and histiocytes) in purulent meningitis, Pus cells, epithelioid cells and cell debris in caseating peritonitis and typhoid ulcer granuloma of lung, lymph nodes and the meninges Inflammatory and epithelial cells of the sputum in bronchitis, Bronchial metaplasia and (reserve cell) hyperplasia pneumonia and sinusitis

Benign tumors, cytologic preparations and tissue sections:

Squamous papilloma and condyloma Amputation neuroma Pulmonary chondroid Tumor (hamartoma) with nourishing vessels Round and spindle cell tumors of the breast (fibroadenoma) Encapsulated fibrous tumor with concretion (calcifying and cystosarcoma (phyllodes tumor) aponeurotic fibroma) of the thigh and buttock Dermoid and papillary cysts of the ovary with calcification and Round and cuneiform tumor of the dura (meningioma) round concretions (psammoma bodies) Fasciculated subcutaneous fibrous tumor (neurofibroma) Cutaneous and uterine fibroids Post amputation fibrous tumor (amputation neuroma) Ordinary lipoma and fibrous (spindle cell) lipoma Chondroma of fingers Hemangioma; cholesteatoma Multinucleated round and spindle cell tumor of the head and Villonodular synovitis maxilla (giant cell tumor)

Malignant tumors:

Dermatofibrosarcoma Encephaloid tumor of the testis with round and giant cells (seminoma and choriocarcinoma) Squamous carcinoma of the buccal mucosa, nose, maxillary antrum, lung, esophagus and the uterine cervix Polypoid sarcoma of the uterus containing diverse cells (mesodermal mixed tumor) Adenocarcinoma of the lung, stomach, colon, ovary and the uterus Carcinoma of the stomach and colon with tumor nodules in the liver showing similar cells (metastases) Scirrhous (firm) carcinomas of the breast, one involved the nipple (Paget’s disease). Fibrous and soft sarcomas of soft tissues Microscopic Contributions of Pioneer Pathologists 205 of microscopic observations by Virchow and the penis; infiltrating (duct) carcinoma of others that had been evolving for decades. the breast; infiltrating cancroids (keratinizing More specifically, by applying the cell theory of squamous carcinoma) of the lip, orbit and Schwann to pathology, he transferred medicine the uterine cervix; myxoma of the abdomen from its ancient humoral foundation to a new (pseudomyxoma peritonei); myxoma of soft footing, the fundamental unit of all living tissues (myxoid liposarcoma); mucous and organisms, the cell, and transformed pathology gelatinous cancers in different organs and into the science of microscopy. In the same locations in the body; fibrous and myogenic book, he established the dictum omnis cellula sarcomas of soft tissues. Virchow believed that e cellula (every cell from a cell) which turned metastases could occur by direct spread through out to be one of the most important axioms in lymphatic and blood vessels or by embolization medical science. He described and illustrated of cancer cells through the lungs resulting in the microscopic appearance of hundreds of cancerous nodules in distant organs [15]. benign and malignant pathologic lesions in his 534 page text [15]. Tumors were perhaps Virchow’s greatest interest, and in 1863, he began publication Virchow divided all new growths into two types, of what was to be a comprehensive treatise homologous and heterologous. Homologous on the subject [16]. It was never completed. growths, mostly benign tumors, were represented He stopped when he reached the point where by an increase in size and number of cells of carcinomas were to be presented, probably the type already present in normal tissues. because of assaults on his erroneous concept of Heterologous tumors were mostly malignant and the histogenesis of malignant epithelial tumors. consisted of a new form of cells that did not exist Although the text is incomplete and contains in normal tissues. Among the benign lesions he mostly gross description and illustration of presented pus cells from sputa, ulcers and body tumors, it remains a substantial source-book on fluids; fatty infiltration of the myocardium; fatty benign and malignant tumors [16]. degeneration of various tissues; hypertrophy and nodular fibrous changes of the liver (cirrhosis); The cellular pathology work of Virchow was ossification of the meninges; tubercularcontinued by his students. Julius Cohnheim granuloma of the lung and pleura; ulcerated (1839-1884) introduced microscopic mitral valve in endocarditis with microscopic examination of fresh frozen tissue (frozen emboli in the splenic artery; thrombosed section) and silver stain. He described hemorrhoid; granular pigment in tattooed skin pseudoleukemia, exostosis, intraosteal sarcoma and adjacent lymph node; fatty degeneration and fatal trichinosis. Edwin Klebs (1834- of the aorta with concretion (atherosclerosis); 1913) introduced paraffin embedding, designed keratitis of the cornea; swollen urinary tubules solid media for bacterial culture, isolated the in Bright’s disease; callus; periosteal ossification diphtheria bacillus and recognized spirillar (osteochondroma or osteoma); hypertrophy of organisms in syphilitic lesions. Friedrich optic nerve (optic neuroma); plexiform and von Recklinghausen (1833-1910) described amputation neuroma. Virchow introduced hyperparathyroidism, polyostotic fibrous many new terms, including parenchymatous dysplasia, mast cells in vessels in connective inflammation and degeneration, amyloidosis tissue and multiple neurofibromatosis and osteoid [15]. (Recklinghausen disease), and introduced the term hemochromatosis. Felix Hoppe-Seyler In the sections on malignant tumors Virchow (1825-1895) introduced the term hemoglobin compared cancer cells in size and shape with and defined its chemical and physiological benign cells and illustrated various forms with characteristics. In addition, he demonstrated distinct microscopic features. He described that hemin is the hydrochlorate of hematin. and illustrated condyloma and carcinoma of 206 Annals of Clinical & Laboratory Science, vol. 41, no. 2, 2011 In conclusion, we now recognize the microscope 4. Schwann T. Ueber die Analogie in der Structur und dem Wachsthum der Thiere und Pflanzen. 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