Method of examination of tissues and cells

Introduction

• Histopathology = Tissues ka microscope ke through study, disease ko detect karne ke liye.

• Cytopathology = Cells ka study microscope ke under.

Ye dono disease detection, cancer diagnosis, prognosis aur research ke liye bahut important hain.

Lab me examination ke do main tareeke hote hain:

1. Tissue Examination (Histopathology)

2. Cell Examination (Cytopathology)

 

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Tissue Examination 

Yahaan pura tissue sample ko process karke examine kiya jata hai.

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A. Biopsy

• Matlab: Zinda patient se chhota tissue piece nikalna diagnosis ke liye.

• Types:

  1. Incisional biopsy – sirf lesion ka ek hissa liya jata hai.

  2. Excisional biopsy – pura lesion nikal diya jata hai.

  3. Needle biopsy – needle se chhota tissue sample liya jata hai.

  4. Endoscopic biopsy – endoscope se (jaise stomach, colon).

• Use: Cancer, infection, chronic disease ka diagnosis.

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B. Surgical Specimen

• Surgery ke time nikale huye organs/tissues.

• Example: Appendix, Gall bladder, Breast lump.

• Pehle gross examination hota hai (size, shape, weight, margins).

• Fir microscopic exam ke liye process kiya jata hai.

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C. Autopsy

• Dead body se tissue ka examination.

• Types:

  • Clinical autopsy (cause of death ke liye).

  • Medico-legal autopsy (suspicious cases).

• Disease ke natural history aur treatment response samajhne me help karta hai.

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D. Tissue Processing

Tissue ko microscope ke liye tayaar karna:

1. Fixation → Formalin me dal kar tissue ko preserve karte hain.

2. Dehydration → Alcohol series me dal kar paani nikalte hain.

3. Clearing → Xylene se alcohol replace karte hain.

4. Embedding → Paraffin wax block banate hain.

5. Sectioning → Microtome se 3–5 micron thin sections banate hain.

6. Staining → Hematoxylin & Eosin (H&E) sabse common.

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E. Special Stains

• PAS → glycogen, mucin.

• Ziehl–Neelsen → TB bacilli.

• Silver stain → fungus, reticulin fibers.

• Congo red → amyloid (apple-green birefringence).

• Masson’s Trichrome → collagen.

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F. Immunohistochemistry

• Antibody–antigen reaction ke zariye proteins ko detect karna.

• Example:

  • Breast cancer me ER, PR, HER2.

  • Ki-67 proliferation marker.

• Diagnosis + prognosis + treatment ke liye useful.

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G. Frozen Section

• Tissue ko cryostat me turant freeze karke section banate hain.

• Surgery ke time quick diagnosis ke liye use hota hai.

• Example: Tumor margin check karna.

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H. Electron Microscopy

• Bohot high magnification pe organelles, viruses, basement membrane details dikhata hai.

• Renal biopsy, muscle diseases, viral studies me kaam aata hai.

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Cell Examination 

Yahaan sirf cells ka study hota hai, tissue architecture preserve nahi hota.

A. Exfoliative Cytology

• Jo cells naturally shed hote hain unka study.

• Example: Pap smear – cervical cancer screening.

• Aur examples: Sputum cytology, Urine cytology.

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B. Fine Needle Aspiration Cytology (FNAC)

• Fine needle se lump ya swelling se cells nikal kar slide par smear banate hain.

• Stains: Papanicolaou, Giemsa.

• Advantages: Quick, cheap, OPD me possible.

• Use: Breast, thyroid, lymph node, salivary gland lumps.

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C. Body Fluids Cytology

• Fluids jaise Pleural, Peritoneal, CSF, Synovial fluid ka exam.

• Malignant cells ya infections detect karte hain.

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D. Imprint Cytology

• Fresh tissue ko slide par press karke imprint banate hain.

• Rapid diagnosis in lymph node, breast, thyroid.

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E. Cytochemistry

• Special stains ka use chemical nature dekhne ke liye.

• Example:

  • PAS → glycogen.

  • Sudan Black → lipids.

  • Peroxidase stain → myeloid cells.

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F. Flow Cytometry

• Cell suspension ko laser ke through pass karte hain.

• Antibody markers detect karne ke liye fluorescent tags use hote hain.

• Uses: Leukemia/lymphoma classification, minimal residual disease detection.

 

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Tissue vs. Cell Examination: Comparison