Page 282 - Textbook of Pathology, 6th Edition

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Chapter 11
Chapter 11 Basic Diagnostic Cytology*

iii) In some fields, cytodiagnosis has replaced histopatho-
SECTION I
INTRODUCTION
logy as the primary method of establishing a tissue diagnosis
The last chapter in General Pathology deals with the e.g. in breast cancer, where positive cytologic report is
techniques and applications of basic cytologic methods in a considered sufficient for planning the management,
diagnostic pathology laboratory. obviating the need for diagnostic surgical biopsy.
As mentioned in the beginning of this book, surgical iv) Cytodiagnosis has a major role in the detection and diag-
pathology developed as a prospective diagnostic branch nosis of clinically silent early cancer e.g. carcinoma in situ of
around the turn of 19th Century. Its basis was application of the uterine cervix.
knowledge of morphological details of cells for diagnosis of v) In the management of cancer, cytodiagnosis may help in
disease in biopsy material. This generated interest of workers assessing response to therapy e.g. cervical smears for response
towards obtaining cellular material by non-biopsy techniques to radiotherapy in carcinoma cervix, and urinary cytology
to arrive at the diagnosis. As a result, cytopathologic for response to chemotherapy in carcinoma of the urinary
diagnosis was initially introduced purely as Exfoliative bladder.
Cytology in the 1920s by Dr. George N. Papanicolaou. vi) In the follow-up of previously diagnosed cases of cancer,
Subsequently, success of bone marrow aspiration for diagnosis it is of particular value in detecting dissemination (metastasis)
of haematopoietic diseases generated interest in aspiration or recurrence of tumour.
biopsy for diagnosis of solid lesions in the 1930s, which 2. Identification of benign neoplasms. This application is
evolved over the next three decades mainly in Scandinavian derived from its ability to distinguish between benign and
countries in Europe and later spread to the rest of the world
to become the mainstay branch of diagnostic cytology known malignant neoplasms e.g. fibroadenoma of the breast versus
carcinoma.
as Interventional Cytology.
In general, diagnostic cytology pertains to the 3. Intraoperative pathologic diagnosis. In this role, cyto-
General Pathology and Basic Techniques
interpretation of cells from the human body that either diagnosis complements histopathologic diagnosis e.g.
exfoliate (desquamate) spontaneously from epithelial imprint smears alongwith frozen section for breast lumps.
surfaces, or the cells are obtained from various organs/ 4. Diagnosis of non-neoplastic/inflammatory conditions.
tissues by different clinical procedures. While histopathologic Cytodiagnosis allows recognition of specific conditions which
diagnosis is based on interpretation of changes in tissue
architecture, the cytopathologic diagnosis rests upon
alterations in morphology observed in single cells or small  TABLE 11.1: Nuclear Criteria of Malignancy.
groups of cells. 1. Nuclear size : Usually larger than benign nuclei;
variation in size (anisonucleosis) more
Role of Diagnostic Cytology significant.
2. Nucleus-cytoplasmic : Increased.
Among the numerous applications of cytodiagnostic (N:C) ratio
techniques, the following are more important:
3. Nuclear shape : Moderate to marked variation.
1. Diagnosis and management of cancer. In the field of 4. Nuclear membrane : Irregular thickening, angulation and
oncology, establishing a ‘tissue diagnosis’ (i.e. pathologic indentations.
diagnosis based on microscopic evidence of malignancy) is 5. Nuclear chromatin : Hyperchromatic (less significant),
an essential pre-requisite for proper management of a cancer uneven distribution, coarse irregular
patient. angulated chromatin clumping,
parachromatin clearing (more signi-
i) Cytodiagnosis in its traditional role is a valuable adjunct ficant).
to histopathology for establishing the vital tissue diagnosis
e.g. diagnosis of lymphomas where imprint smears prove 6. Nucleoli : Increased size and number less
significant; irregular angular outlines
valuable, and in some respects superior to histopathology more significant.
in typing the lymphoma. 7. Number of nuclei : Multinucleation unreliable; nuclear
ii) Cytologic techniques also provide a preliminary diagnosis character more important.
of cancer for later confirmation by histopathology e.g. 8. Mitoses Increased mitoses unreliable; abnormal
detection of ovarian cancer cells in ascitic fluid. mitoses significant.

*The contribution of this chapter by Dr Rohit Sharma, MD, to the second edition of this book (1994) is gratefully acknowledged.