Stains
PAS (Periodic Acid-Schiff)

Author: Nat Pernick, M.D. (see Authors page)

Revised: 1 December 2016, last major update June 2005

Copyright: (c) 2002-2015, PathologyOutlines.com, Inc.

PubMed Search: PAS [title]

Cite this page: PAS (Periodic Acid-Schiff). PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/stainspas.html. Accessed December 3rd, 2016.
Definition / General
  • A special stain, not an immunostain
Etiology
  • Substances with nearby glycol groups or their amino or alkylamino derivatives are oxidized by periodic acid to form dialdehydes, which combine with Schiff's reagent to form an insoluble magenta compound
  • Used for formalin fixed tissue and enzyme cytochemistry; can be used for frozen sections with modifications (Eur J Gynaecol Oncol 1998;19:482, Am J Surg Pathol 1992;16:87)
  • Stains basement membrane (normal and in tumors), glycogen, some mucins (see below) and mucopolysaccharides
  • A routine stain in brain (with Luxol fast blue), cornea, kidney, liver and skeletal muscle specimens for nontumor pathology
  • Some mucins (see below) are PASD (PAS with predigestion with diastase) positive (i.e. stain is present after diastase predigestion; also called diastase resistant); glycogen is PASD negative (also called diastase sensitive because diastase removes PAS staining)
  • PAS stains neutral and acid-simple non-sulfated and acid-complex sulfated mucins
  • PAS does NOT stain acid-simple mesenchymal mucins and acid-complex connective tissue mucins
  • Also stains various inclusions, bodies, granules and secretions composed of mucopolysaccharides or mucins
Uses by Pathologists
  • Breast cytology: PASD positive cells with internal structure and producing nuclear indentation, particularly in dissociated or atypical cells, correlate with malignant histology (J Clin Pathol 2001;54:146)
  • Fungi: stains fungal cell walls; PAS+ granule at anterior end of mature spores is diagnostic of microsporidia (BMC Clin Pathol 2006;6:6)
  • Hematopathology: ALL, AML M5-M7 are PAS+
  • Kidney: recommended for routine evaluation of renal biopsies due to basement membrane staining; also useful to diagnose renal cell carcinoma (stains glycogen, removed by diastase)
  • Liver: routine stain; also stains inclusions of alpha-1-antitrypsin disease
  • Lung: stains amorphous or granular globules in BAL fluid in pulmonary alveolar proteinosis (J Clin Pathol 1997;50:981)
  • Muscle biopsies: routine stain to demonstrate glycogen
  • Pancreas: acinar cell carcinoma (PASD+)
  • Parotid glands: zymogen granules are PAS+
  • Prostate: Cowper’s glands are PASD+ (Am J Surg Pathol 1997;21:550)
  • Skin: eosinophilic globoid bodies (Kamino bodies) in Spitz nevus are PASD+
  • Small intestine: stains Whipple’s disease bacteria (Am J Clin Pathol 2002;118:742, Hum Pathol 2003;34:589); strong cytoplasmic staining present in microvillous inclusion disease versus linear brush border staining in normals (Am J Surg Pathol 2002;26:902)
  • Testis: stains intratubular germ cell neoplasia (Am J Surg Pathol 1994;18:947) and seminoma (PAS+, PASD negative), but not normal seminiferous tubules
  • Tumors: adenocarcinoma of various sites (mucin is PASD+), alveolar soft parts sarcoma (PASD+ crystalline structures), apocrine carcinomas, basement membrane containing tumors (cylindroma [Am J Surg Pathol 2001;25:823], eccrine spiradenoma), clear cell tumors (stains glycogen), glycogen rich carcinomas, glycogen rich/balloon cell melanoma (Arch Pathol Lab Med 1998;122:353), granular cell tumor (cytoplasmic granules), hyaline globules in renal tumors (Hum Pathol 1997;28:400), mucinous tumors, Paget’s disease of breast
  • Other: stains malakoplakia
  • Enzyme cytochemistry: coarse granular staining
Micro Images
Scroll to see all images.

Images hosted on PathOut server:

Courtesy of Andrey Bychkov, M.D., Ph.D.

Graves disease

PAS-D staining of PTC with laryngeal invasion



Kidney:

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Nodular glomerulosclerosis



Case of the Week #51:

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Tubulocystic carcinoma, kidney (tumor)



Images hosted on other servers:

Bacteria:

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Atypical mycobacteria

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Rhodococcus PAS+, colonic histiocytes

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Rhodococcus PAS+, pulmonary histiocytes

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Tropheryma whipplei histiocytes, hippocampus



CNS:

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Acquired hepatocellular degeneration

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Secretory meningioma



CNS:

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Malakoplakia



Cornea:

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Fuch's dystrophy



Fungi:

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Blastomyces

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Candida of esophagus

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Lung

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Tongue

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Coccidioidis immitis, tongue

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Cryptococcal meningitis

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Histoplasmosis, colon, HIV+ woman

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Microsporidia

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Mucor of stomach



Heart:

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Glycogen storage disease



Kidney:

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Normal

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Alport syndrome

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Alport syndrome, fetal glomerulus

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Amyloidosis

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Chronic pyelonephritis

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Dense deposit disease

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Fabry's disease

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Focal segmental glomerulosclerosis

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Henoch Schoenlein purpura

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IgA nephropathy

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Immunotactoid glomerulonephritis

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Membranoproliferative glomerulonephritis type I

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With crescent

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Doubling of capillary wall

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Nephronophthisis

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Nodular glomerulosclerosis

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SLE

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Thrombotic microangiopathy



Liver:

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Alpha1 antitrypsin deficiency

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Hepatitis A with confluent necrosis



Lung:

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Pneumocystis pneumonia

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Pulmonary alveolar proteinosis

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Hyaline membrane disease



Parasites:

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Acanthamoeba histolytica

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Echinococcus, bone



Parotid gland:

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Normal



Skeletal muscle:

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AS+ diastase sensitive material in McArdle’s disease



Skin:

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Fabry disease



Small intestine:

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Various images



Tumors:

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Acinar cell carcinoma, pancreas

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Adenocarcinoma, colon

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Alveolar soft parts sarcoma in cervix

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Clear cell acanthoma

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Clear cell carcinoma, ovary

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Cylindroma

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Eccrine spiradenoma

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Ewing sarcoma

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Glycogen rich carcinoma, breast

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Granular cell tumor

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Kaposi sarcoma

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Lymphoplasmacytic lymphoma

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Mucinous cystadenoma, ovary

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Secretory meningioma

Positive Staining - Normal
  • Basement membrane, fungi, glycogen (removed after diastase or amylase predigestion), mucins (neutral and acid-simple non-sulfated and acid-complex sulfated types), surfactant
Positive Staining - Disease
  • ALL (75%, block staining), alpha-1-antitrypsin inclusions, alveolar soft part sarcoma (intracytoplasmic crystals), AML-M5a, M6 (60%), M7, basement membrane containing tumors (cylindroma), clear cell tumors, malakoplakia, renal cell carcinoma (PAS+ glycogen removed with diastase), parasites
Negative Staining
  • Mucins (acid-simple mesenchymal and acid-complex connective tissue types)