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An approach to microscopic interpretation


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An approach to microscopic interpretation

  1. 1. Introduction to microscopic interpretation<br />Dr. Santosh Rathod<br />
  2. 2. Have your eyes and mind open<br />Processing the acquired visual information<br />Arriving at a tentative diagnosis (ie, model building)<br />Testing the preliminary diagnosis with further examination<br />Confirming the diagnosis<br />Correlating available clinical information<br /> Finalizing the diagnosis<br />
  3. 3. From where to start?<br />
  4. 4. Examination of the Slide with the Naked Eye<br />To gain some appreciation of the size, number, and nature of the histologic sections on the slide<br />The tinctorial properties (histochemical staining) also may provide clues to diagnosis;<br />For example,bluish cellular aggregates or nodules suggest high nuclear-to-cytoplasmic ratios because of basophilic staining of nuclei and, as a result of processes such as basal cell carcinoma, small cell carcinoma, and infil- trates of small lymphocytes or calcium deposition. <br />
  5. 5. Examination of the MicroslideatScanning(2 X or 4X) Magnification<br />Firstly, one should attempt to identify the type of specimen submitted<br />Then, inspect the specimen with the idea of determining in general terms from what anatomic site the tissue was taken.<br />Entire specimen (ie, epidermis, dermis, or subcutis) should be scanned<br /> - for the principal site of involvement by a disease process, if any, and<br /> - the nature of the process, whether inflammatory <br /> proliferative, <br /> inflammatory and proliferative or <br /> non-inflammatory.<br />
  6. 6. Examination at IntermediateMagnification<br />The tendency to go to higher magnification too soon should be resisted because one often will overlook a crucial feature, and thus, in effect, one “cannot see the forest for the trees.”<br />The reasons for closer inspection of the specimen (with 10Xand 40X objectives) are to confirm particular features of pathologic processes<br />For identification of specific cell types, such as lymphocytes or granulocytes<br />
  7. 7. Normal histology of skin<br />St. Corneum<br />St. Granulosum<br />St. Spinosum<br />St. Basale<br />Pappilary dermis<br />Reticular Dermis<br />
  8. 8. Identification of cells<br />Type of cells normally present in epidermis :<br />Majority are - Keratinocytes (90%)<br />Minority population of – Langerhans cells<br />Melanocytes<br />Neuroendocrine(Merkel Cells)<br />Unmyelinated axons<br />Occasional Cells – Toker cells found in nipple epidermis in <br /> approximately 10% individuals<br />
  9. 9. s<br />Granular keratinocyte<br />Spinouskeratinocyte<br />Basal keratinocyte<br />
  10. 10. Langerhans cells<br />Marrow derived<br />Dendritic<br />Antigen presenting cells<br />In H&E sections, appear as clear cells<br />Special stains are generally required for their detection and enumeration<br />
  11. 11. melanocyte<br />Melanin synthesizing dendritic cells<br />Located within basal layer of epidermis, hair bulb, ORS<br />In H&E stained section, dendritis are not visible, cell bodies can be seen dispersed in basal layer<br />Contain round to oval, dark stained nuclei that are generally smaller than basal keratinocyte<br />
  12. 12. Dermis<br />Cellular content :<br /> Fibroblasts<br /> Dermal dendritic cells<br /> Macrophages<br /> Mast cells<br />Extra-cellular content :<br /> Collagen<br /> Elastic fibres<br /> Ground substance<br />
  13. 13. Dermal fibroblast<br />Appear as inconspicuous bipolar spindle cells with elongated ovoid nuclei<br />Can’t be reliable distinguished from other dermal spindle shaped and dendritic cells ( dermal dendrocytes)<br />Synthesizes collagen<br />IH stain – Vimentin<br />
  14. 14. Phagocytic macrophages<br />Also, called Histiocytes<br />Are of bone marrow origin, circulate in blood as precursors and enter tissue as monocytes<br />Activated monocytes – macrophages<br />Aggregation of activated macrophages – granulomas<br />Macrophages that have ingested melanin- melanophages<br />Macrophages that have ingested hemosiderin - siderophages<br />
  15. 15. Monocytes are indistinguishable by routine histology from lymphocytes as both have a small, dark, rounded nuclei with very scanty cytoplasm<br />
  16. 16. Macrophages are larger cells than monocyte and possess a vesicular, light staining, elongated nuclei with a clearly visible nuclear membrane<br />
  17. 17. Emigrant inflammatory cells<br />Neutrophilic granulocytes<br />Eosinophilic granulocytes<br />Basophilic granulocytes<br />Lymphocytes<br />Plasma cell<br />
  18. 18. Neutrophilic granulocyte<br />Polymorphonuclearleucocyte<br />Lobated “pop-corn” shaped nuclei within pale pink fairly granular cytoplasm<br />Nuclear breakdown due to local necrosis or by autodigestion of nuclear lobes as in vasculitis results in “nuclear dust” of vasculitis<br />
  19. 19. Eosinophilic granulocyte<br />Characterized by strongly eosinophilic granules in cytoplasm and a characteristically bilobed nuclei<br />Although visible with routine stains, these granules stand out more clearly in brilliant red when stained with giemsa<br />
  20. 20. Plasma cell<br />Have abundant cytoplasm that is deeply basophilic, homogenous and sharply defined<br />Round eccentrically placed nuclei along its membrane it shows course, deeply basophilic, regularly distributed chromatin particles which gives “cart-wheel” appearance<br />
  21. 21. Methods of diagnosis in dermatopathogy<br />Initial stage of pattern - by the process of hypothesis <br />recognition by a “gestalt” generation and differ-<br /> based or instant recognition tial diagnosis<br />Pattern recognition method by Ackerman<br />
  22. 22. Inflammatory Dermatopathology by Pattern and Algorithm<br />Steps <br />Categorize the pattern<br />Assess the inflammatory cell population<br />Look for specific findings that direct the algorithm as far as it can be taken<br />Correlate the histologic assessment with known clinical information<br />
  23. 23. Superficial PerivascularDermatitis<br />Superficial and Deep Perivascular Dermatitis<br />Nodular and Diffuse Dermatitis<br />Panniculitis<br />Vasculitis<br />Folliculitisand Perifolliculitis<br />IntraepidermalVesicular and Pustular Dermatitis<br />Subepidermal Vesicular Dermatitis<br />
  24. 24. Thank you<br />