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Confusing Carbs!! – Carbohydrate staining simplified

Carbohydrate staining is confusing isn’t it? Lets try and simplify it!

(Staining procedures and methods will not be discussed, only the interpretation)

PAS and Alcian blue staining will be discussed

TABLE OF CONTENTS
1. Types of carbohydrates
2. PAS( Periodic acid Schiff) staining
3. Alcian blue staining
4. Combined PAS + Alcian blue staining
5. Combined Alcian blue + High iron diamine staining
6. Summary
TABLE OF CONTENTS

1.TYPES OF CARBOHYDRATES

Group 1: Neural Polysaccharides or non-ionic homoglycans: This group has glucose containing glycogen, starch and cellulose as well as N-acetyl glucosamine containing chitin.

Group 2: Acid mucopolysaccharides or anionic heteroglycans: Hyaluronic acid and Chondroitin sulfate belong to this group.

Group 3: Neutral mucins, Carboxylated mucins (sialomucins) as well as sulfated mucins (sulfomucins) are present in this category.

NEUTRAL MUCINS CARBOXYLATED MUCINS SULFATED MUCINS
  • Surface epithelia of the stomach

  • Brunner glands of the duodenum

  • Prostatic epithelium
  • Bronchial submucous glands

  • Goblet cells

  • Salivary glands
  • Bronchial mucus glands
    Group 3

    Remember: Carboxylated mucins or sialomucins (also called simple mucins) are weak acids whereas sulfated mucins (also called complex mucins) are strong acids

    Group 4: Glycolipids and Phosphatides belong to this group.

    WHICH OF THESE GROUPS IS PAS (PERIODIC ACID SCHIFF) POSITIVE?

    Group 1 is always PAS positive

    Group 2 is always PAS negative.

    Group 3 and 4 is also PAS positive.

    Remember: Mesenchymal polysaccharides such as Hyaluronic acid and Connective tissues polysaccharides such as Chondroitin sulfate are always negative for PAS.

    carbohydrate staining- PAS stained gastric foveolar cells
    Carbohydrate staining – Periodic acid-Schiff (PAS) stain -Positive gastric foveolar cells6. SUMMARY OF CARBOHYDRATE STAINING

    PAS Positive cell and tissue components

    1.Glycogen
    2.Starch
    3.Mucins (Neutral mucins>sialomucins>sulfomucins)
    4. Basement membranes
    5. α-antitrypsin
    6.Reticulin
    7.Fungi (capsules)
    8.Pancreatic zymogen granules
    9.Thyroid colloid
    10.Corpora amylacea
    11. Russell bodies

    Carbohydrate staining- Periodic acid-Schiff (PAS) stain highlights the microvillous along the apical surface of the absorptive cells.
    Carbohydrate staining- Periodic acid-Schiff (PAS) stain highlights the microvillous along the apical surface of the absorptive cells.

    Diseases in which PAS staining can be used for diagnosis

    1. Glycogen storage disease
    2. Adenocarcinoma
    3. Paget’s disease of the breast
    4. Staining macrophages in Whipple’s disease
    5. Fungal infection
    6. Alveolar soft part sarcoma
    7. Erythroleukemia
    8. α1-antitrypsin deficiency
    9. Ewing sarcoma
    10. Pulmonary alveolar proteinosis

    3. LET’S MOVE ON TO ALCIAN BLUE STAINING

    Group 1 is always Alcian blue negative

    Group 2 is always Alcian blue positive. Hyaluronic acid is positive at a pH of 2.5 and Chondroitin sulfate is positive at a pH of 0.5.

    Group 3 is the confusing part, we need to divide it into three parts for better understanding

    1.Neutral mucins– Always alcian blue negative.

    2. Sialomucins or carboxylated mucins– Alcian blue positive at a pH of 2.5

    3. Sulfated mucins– Alcian blue positive at a pH of 1.

    Group 4 is Alcian blue negative.

    Alcian blue staining of barrett mucosa
    Alcian blue staining of Barrett mucosa at a pH of 2.5- Goblet cells are stained blue and gastric mucous cells are clear.

    Alcian blue stain is frequently combined with PAS and High iron diamine for diagnostic purposes (discussed below).

    Alcian blue staining of cartilage at pH 0.5
    Alcian blue staining of cartilage at pH 0.5

    4. COMBINED PAS AND ALCIAN BLUE STAINING

    Primary use of PAS+Alcian blue combined staining is to distinguish neutral and acidic especially sialomucns.

    Diagnostic utility: 1. To distinguish eccentric gastro-esophageal junction from Barret’s mucosa

    2. Gastric intestinal metaplasia

    Remember: Key finding an diagnostic feature intestinal metaplasia is the presence of goblet cells. Goblet cells and surface epithelial cells of stomach may be difficult to distinguish in routine Hematoxylin and Eosin stained sections.

    Goblet cells are positive with both PAS and Alcian blue but gastric epithelial cells are positive with PAS alone. When combined PAS+Alcian blue staining is performed, Goblet cells stain PURPLE and Gastric foveolar cells stain MAGENTA.

    Batter esophagus showing goblet cells
    Barrets esophagus showing goblet cells
    PAS + Alcian blue stain showing purple colored goblet cells and magenta colored gastric foveolar cells
    PAS + Alcian blue stain showing purple colored goblet cells and magenta colored gastric foveolar cells at pH 2.5.

    5. COMBINED ALCIAN BLUE AND HIGH IRON DIAMINE

    Combined PAS + High iron diamine is used to distinguish between sulfomucins and sialomucins.

    Diagnostic utility: Large bowel metaplasia can be identified, since it contains both sulfomucins and sialomucins, in contrast to small bowel metaplasia (sialomucins only)

    With Alcian blue + High iron diamine staining- Sulfomucins: BROWN COLOR and Sialomucins: BLUE COLOR

    Carbohydrate staining- Sulfomucins stained brown with High iron diamine and few sialomucins stained blue.
    Sulfomucins stained brown with High iron diamine and few sialomucins stained blue.

    6. SUMMARY OF CARBOHYDRATE STAINING

    1. PAS is always negative in mesenchymal and connective tissue mucopolysaccharides
    2. Alcian blue is always negative in neutral mucins
    3. PAS+Alcian blue is key to distinguish ectopic gastric mucosa or eccentric gastroesophageal junction from Barret’s mucosa in the esophagus.

    Comment your queries and suggestions!! Thank you!

    Check this link for Key Points on Hematoxylin and eosin staining

    Posted in Hematology, Hematopathology, Histopathology

    Differences between Kimura disease and Angiolymphoid hyperplasia with eosinophilia

    Kimura disease and Angiolymphoid hyperplasia with eosinophilia (ALHE) are often confused and need to be differentiated. Here are a few differences.

    1.AGE

    Kimura’s disease is a chronic inflammatory condition of unknown cause that affects young to middle-aged patients, most often males of Asian descent. Whereas, ALHE is more common in females.

    2.LOCATION

    Kimura disease patients usually have a mass in the head and neck region with involvement of subcutaneous tissue, soft tissue, salivary glands, and single or multiple regional lymph nodes. ALHE also commonly involves the head and neck region, particularly behind the ears.

    3.HISTOLOGY

    Key histologic features of kimura disease includes florid follicular hyperplasia that may contain a proteinaceous precipitate (IgE in a follicular dendritic network pattern) and vascularization of the germinal centers. The interfollicular areas show prominent high endothelial venules with a mixture of lymphocytes, plasma cells, eosinophils, and mast cells. Follicle lysis is often present, and eosinophilic abscesses are characteristic within germinal centers as well as in the paracortex.

    ALHE on the other hand, is a vascular neoplasm characterized by the proliferation of blood vessels lined by plump endothelial cells with abundant eosinophilic cytoplasm, imparting a hobnail appearance. This lesion is part of the spectrum of what have been called histiocytoid or epithelioid hemangiomas, and is a low-grade vascular tumor. There is a dense, mixed inflammatory cell infiltrate consisting of lymphocytes, plasma cells, and eosinophils.

    4. IMMUNOHISTOCHEMISTRY

    Reticular pattern of IgE is seen in KIMURA disease. However, immunohistochemistry in ALHE is positive for CD 31, CD 34 and Factor VIII in the vascular component.

    5.PERIPHERAL BLOOD EOSINOPHILIA

    Peripheral blood examination shows eosinophilia and increased serum IgE levels in kimura disease but not so much in ALHE.

    FIND A QUICK SUMMARY BELOW

    REVIEW QUESTION

    1. A 20- year- old Asian male has eosinophilia and high levels of IgE with cervical lymphadenopathy. Excisional biopsy of the lymph node demonstrates follicular hyperplasia, intense eosinophilia and eosinophilic microabscesses. h e most likely diagnosis is:

    A. Kimura disease

    B. Kikuchi- Fujimoto disease

    C. Eosinophilic leukemia

    D. Hypereosinophilic syndrome

    CLICK TO REVEAL ANSWER

    Answer is A- Kimura disease like Kikuchi disease is seen more ot en in the Asian population. h e etiology is not known. h is is a chronic inl ammatory disorder of the subcutaneous tissue and af ects regional lymph nodes. h e cervical area is the most common site to be involved. Histology of the af ected lymph nodes demonstrates follicular hyperplasia, eosinophilia with eosinophilic microabscesses and ini ltration of the germinal centers. Increase in vessels may also be seen. Warthin Finkeldey giant cells may also be present.

    2. All are true about kimura disease except

    A. Affects asians

    B. Affects females

    C. Peripheral eosinophilia is present

    D. Elevated levels of IgE are seen

    CLICK HERE TO REVEAL ANSWER

    Answer is B- Kimura disease is more common in males.

    Posted in Hematology, Hematopathology

    HEMOPHILIA B LEYDEN- A rare form of FIX deficiency

    HEMOPHILIA B LEYDEN is a rare form of FIX deficiency

    Here are some key points to be noted regarding Hemophilia B Leyden.

    1. It is a rare form of FIX deficiency, hemophilia B Leyden, undergoes postpubertal phenotypic resolution.
    2. Patients with this condition present with hemophilia B in early childhood, with FIX activity ranging from less than 1% to 13% of normal.
    3. Plasma levels rise to as high as 70% of normal after the onset of puberty with resolution of bleeding complications.
    4. Mutations in hemophilia B Leyden have been identified in the promoter region of the FIX gene, within which a consensus sequence for steroid receptor binding is located.

    REVIEW QUESTION- A QUESTION FROM DM HEMATOPATHOLOGY PGIMER ENTRANCE

    CLICK TO REVEAL THE ANSWER

    ANSWER is C: Steroid receptor is involved in the pathogenesis.

    Posted in Hematology, Hematopathology, TEST YOUR KNOWLEDGE

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