Electron microscope observations cells in the cervix

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1 Electron microscope observations cells in the cervix on Langerhans M. S. YOUNES, M.D.* E. M. ROBERTSON, M.D., F.R.C.O.G. SERGIO A. BENCOSME, M.D., PH.D. Philadelphia, Pennsylvania, and Kingston, Ontario, Canada Clear cells, identical in fine structure to Langerhans cells of the human epidermis, occur in the intercellular spaces of the squamous epithelium of the cervix. There is an apparent increase in the number of Langerhans cells in the cervical epithelia from cases with carcinoma in situ. Langerhans cells of the cervix are frequently mistaken for lymphocytes or for epithelial cells that have undergone cytoplasmic shrinkage. Th.e proper identification of Langerhans cells and other clear cells in the cervical epithelium may eliminate some unnecessary confusiotl in the interpretation of cellular changes in neoplasia. I N T H E c 0 u R s E of an electron microscope study on the normal cervix and cervices with carcinoma in situ, we were impressed by the frequent observation of a certain type of clear cells lodged among the squam.ous epithelial cells of the ectocervix. Under the light microscope, these cells were distinguishable from the adjacent epithelial ceils by their relatively smaller but hyperchromatic nuclei and by their clear translucent cytoplasm. The latter appearance could be easily mistaken fo r that of a lymphocyte or an epithelial cell which has From the Department of Obstetrics and Gynecology of the Jeflerson Medical College, Philadelphia, and the Departments of Pathology and Obstetrics an,d Gynecology, Queen s University, Kingston. Supported by Research Grants T-422 from the American Cancer Society and CA from the National Cancer Institute. The earlier part of this work was supported by a Research Grant from the Ontario Cancer Treatment an,d Research Foundation. Presented in part at the Fifteemh Annual Meeting of The American Society of Cytology, October, 1967, Denver, Colorado. Present address: Jeferson Medical College, 1025 Walnut Street, Philadelphia, Pennsylvania undergone cytoplasmic shrinkage. Examination of a large number of electron microscopy sections showed that we were not dealing with a preparation artifact but with special cells identical in fine structure to the Langerhans cell of the human epidermis. In the skin, two types of clear cells are known to occur among the cells of the epidermis. These are the melanocytes and Langerhans cells. While melanocytes are known to produce melanin granules, the origin and function of Langerhans cells are still disputable subjects. l-l1 Both types of clear cells of the epidermis have been studied thoroughly by various light and electron microscopists interested in dermatologic pathology Review of the literature indicates that Langerhans cells have not been known to occur in the cervix. The purpose of this paper is to report on the observation of Langerhans cells in the squamous epithelium of the normal cervix and in cervices with carcinoma in situ. An account of the morphology of these cells will be given. Material and methods The observations to be reported are based on, the study of cervical tissues obtained from 397

2 12 padents with nomnna; cewices dnnd k0i patients with carcinoma in situ, as shown by light microscopy of either cone biopsy or hysterectomy specimens, Tissue blocks were raken from random sites from al 22 cervices and processed for electron microscopy. Small pieces of tissue were fixed in CauL field s fixative,23 dehydrated in a graded series of ethanol solutions, and embedded in Epon 812. z4 Thin sections were cut on Porter-Hum Mt.-2 or Mt-1 ultramicrotomes. Most sections were stained with uranyl acetate in methanop5 and then double stained with lead citrate.26 A few sections were stained with iridium trichloride as follows: the grids containing the sections were immersed in absolute acetone for 3 minutes, then stained with a 25 per cent solution of iridium trichloride for 30 minutes. The grids were rinsed briefly in methanol and then stained with uranyl acetate in methanol.z5 All sections were examined with the Hitachi Light microscopy ill parabin-eml?eddeo, lematoxylin and e&n-stained sections showed clear cells in both normal and in situ epithelia. Clear cells were characterized jy small hyperchromatic nuclei and a trans-?ucent cytoplasm which differentiated them r rom adjacent epithelial cells (Fig. 1) I Although some clear ceils could be identified as inflammatory cells, the nature of others could not be ascertained by light microscopy a?one. Cursory examination of histologic preparations indicated an increase in the number of clear cells in the sections from carcinoma in situ cases. Under the electron microscope, cells with fine structural features, identical to Langerhans cells of the epidermis, were found among the epithelial cells of cervices with Fig. 1. Squamous epithelium of the cervix lrom a patient with carcinoma m situ. Clear c&s ~(arrows) are characterized by small hyperchromatic nuclei and translucent cytoplasms. 8; Hematoxylin and eosin staining. )

3 Volume 102 Number S Langerhans cells in cervix 399 Fig. 21. Low-power micrograph showing a Langerhans cell among squamous epithelial cells of the cervix. The Langerhans cell has a nucleus (Nl) which is darker than that of adjacent epithelial cells (NZ), the cytoplasm of Langerhans cell contains characteristic granules (arrows), Details of the area within the insert are shown in Fig. 3. (~18,600.)

4 Fig. 3. Higher magnification of the insert in Fig. 2 showing a portion of the nucleus of a Langerhans cell (NJ and the cytoplasm containing the characteristic granules (arrows). In this plane of sectioning the granules appear rod-shaped and contain central linear densities. Ch41, cell membrane of Langeshans cell; CM2, cell membrane of an adjacent epithelial cell;.e#, cytoplasm of epithelial cell; M, mitochondria. (~70,000.) carcinoma in situ but less frequently in the tain ton&laments and is genera:ly 9i-- iaw epithelium of norma! cervices. The Langer- electron density (Figs. 3 and 4). There are hans cell has an idented nucleus which ap- no desmosomal attachments between the pears darker than that of adjacent epithelial plasma membranes of Langerhans cells and cells (Fig. 2). Unlike epithelial cells, the epithelial cells (Figs. 3 and 4). Langerhans cytoplasm of Langerhans cells does not con- cells contain the usual array of organelles

5 Langerhans cells in cervix 401 Fig. 4,. Details of structure of a cervical squamous epithelial cell. In contrast to Langerhans cells the cytoplasm of epithelial cells contains tonofilaments (Tf) and the cell is attached to adjacent epithelial cells by desmosomes CD). G, Golgi apparatus; Its, intercellular space; M, mitochondria; N, nucleus. (~31,000.) but, in addition, the cytoplasm shows granules which have been considered characteristic of Langerhans cells of the epidermis9 (Figs. 3 and 5). In the majority of sections these granules appear as rod-shaped bodies which may be attached to terminal vacuoles (Fig. 3). These granules may exhibit different appearances, depending upon the plane of sectioning. The characteristic Langerhans cells granule has been variously described as rod-shaped,27 disk-shaped,le or racket-shaped.5 Recently, serial construction of these granules by Sagebiel and Reedz8 indicated thalt they are made of flattened or curved orthogonal net of particles bounded externally by a limiting membrane and that the granule may be disk-shaped, cup-shaped, or a composite of both shapes. Comment The present work has shown that Langerhans ceils are found in the intercelluiar spaces of the squamous epithelium of the cervix. While this may represent a new finding in the cervix, the presence of Langerhans cells in the epidermal cells of the human skin has long been recognized. Most of the literature dealing with theories on the origin and function of Langerhans cells was concerned with the human epidermis. It is beyond the scope of this paper to discuss in detail all of these theories. Briefly, Langerhans cells have been considered precursors of melanocytes,l postmelanin synthetic cells,5 intraepidermal nerve endings,6 or effete melanocytes.4 It is evident that most of these theories have attempted to either prove or disprove a correlation between Langerhans cells and melanocytes of the epidermis. The application of these theories to the cervix is of very little value, since the latter organ is not known to be the site of active melanogenesis. Recently, the demonstration of the characteristic Langer-

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7 Volume 102 Number 3 Langerhans cells in cervix 403 ham cell granule in a histiocytosis X lesion of the lung and eosinophilic granuloma of bone has cast doubt on the specificity of this type of granule. 28 In brief, the function of Langerhans cells in the cervical m.ucosa remains obscure. It is perhaps worthwhile to mention one of the earlier and widely accepted theories9 dealing with the origin of Langerhans cells. This theory suggests that active melanocytes are found only among the basal epidermal cells and that after completion of their function of melanogenesis they migrate toward the surface, appear as Langerhans cells, and are eventually exfoliated with epithelial ceils.g This theory may be of some significance when applied to the cervix, since the presence of Langerhans cells among exfoliated epithelial cells may cause some unnecessary confusion in the interpretation of cellular changes in neoplasia. The apparent increase in the number of Langerhans cells in carcinoma in situ remains unexplained. In the human skin, increased epidermal cell turnover is associated with a significant increase in the number of Langerhans cells.lg Mishimalg has shown that keratin-stripping of the skin leads to an increased epithelial cell turnover and a subsequent increase in the number of Langerhans cells. It is possible that the observed increase in the number of Langerhans cells in carcinoma in situ may be associated with the abnormal epithelial turnover in this lesion. The nature and function of Langerhans cells and other clear cells in the cervical mucosa in normal and pathologic conditions await further investigation REFERENCES Breathnach, A. S., and Goodwin, E. P.: J. Anat. (London) 99: 377, Wiedmann, A.: Hautarzt 15: 13, Bocharov, I. S.: Dokl. Bolg. Akad. Nauk. 199: 667, Billingham, R. E., and Medawar,.P. B.: Phil. Tr. Roy. Sot. (B) 237: 151, Zelickson, A. S.: J. Invest. Dermat. 44: 201, Ferreira-Marques, J.: Arch. Dermat. u. Syph. 193: 191, Breathnach, A. S.: J. Invest. Dermat. 40: 279, Richter, R.: Arch. Klin. u. Exper. Dermat. 202: Birbeck, M. S., Breathnach, A,. S., and Everall, J. D.: J. Invest. Dermat. 37: 51, Breathnach, A. S., Birbeck, M. S., and Everall, J. D.: Brit. J. Dermat. 74: 242, Breathnach, A. S., Birbeck, M. S., and Everall, J. D.: Ann. New York Acad. SC. 100: 223, Allan, A. C.: Ann. New York Acad. SC. 100: 4.4, Barnicot, N. A., and Birbeck, M. S.: In Montana and Ellis, editors: the Biology of Hair Growth, New York, 1958, Academic Press, Inc Birbeck, M. S. C.: Ann. New York Acad. SC. 108: 540, Breathnach, A. S.: J. Anat. (London) 98: 265, Breathnach, A. S., and Wyllie, L. M.: J. Invest. Dermat. 44: 60, Charles, A., and Ingram, J. T.: J. Biophys. & Biochem. Cytol. 6: 41, Langerhans, P.: Virchow Arch. path. Anat. 44: 325, Mishima, Y.: J. Cell Biol. 30: 417, Silvers, W. K.: Am. J. Anat. 100: 225, Zelickson, A. S., and Hartmann, J. F.: J. Invest. Dermat. 36: 23, Zelickson. A. S.: In Curtis. Arthur Cl.. editor: Electron Microscopy of Skin and Mucous Membrane, Springfield, Illinois, 1963, Charles C Thomas, Publisher. Caulfield, J. B.: J. Biophys. & Biochem. Cytol. 3: 827, Luft, J. H.: J. Biophys. & Biochem. Cytol. 9: 409, Stempak, J. G., and Ward, R. T.: J. Cell Biol. 22: 697, Venable, J. H., and Coggeshall, R.: J. Cell Biol. 25: 407, Zelickson, A. S.: J. Invest. Dermat. 47: 498, Sagebiel, R., and Reed, T. H.: J. Cell Biol. 36: 595, 1968.