Analysis of Classical Histological Special Staining Systems: Application Selection of PTAH, Masson, VG, Elastic Fiber Staining, and Reticular Fiber Staining

The core value of classical histological special staining is to further distinguish structures such as muscle fibers, collagen fibers, elastic fibers, reticular fibers, fibrin, and neuroglial fibers on the basis of HE staining. PTAH, Masson, VG, elastic fiber staining, and reticular fiber staining each have clear application boundaries. Selection should begin with the target structure, followed by consideration of tissue type, lesion background, and result interpretation requirements.

Keywords: special staining; PTAH staining; Masson trichrome staining; Van Gieson staining; VG staining; elastic fiber staining; reticular fiber staining; collagen fiber staining; histological staining

1 Selection Logic of Special Staining Systems

1.1 Define the target structure first

(1) Muscle fibers and fibrin

If the target is to display striations of striated muscle, myocardial structure, fibrin within thrombi, or neuroglial fibers, PTAH is more targeted. It is suitable for observing proteinaceous fibrous structures, but not all blue-stained structures should be directly interpreted as the same tissue component.

(2) Collagen fibers and fibrosis

If the target is to evaluate the extent of fibrosis, degree of collagen deposition, or tissue remodeling, Masson and VG are more commonly used. Masson is suitable for multicolor differentiation among collagen, muscle fibers, and cytoplasm. The VG system is more concise and is commonly used for rapid contrast between collagen and muscle background.

(3) Elastic fibers and vascular structure

If the target is to observe arterial elastic laminae, pulmonary elastic fibers, dermal elastic tissue, or elastic fiber rupture in vascular lesions, elastic fiber staining should be selected, such as Verhoeff, Weigert, orcein, or Victoria blue methods.

(4) Reticular fibers and tissue framework

If the target is to demonstrate the fine reticular scaffold in the liver, spleen, bone marrow, lymph nodes, endocrine glands, or tumor stroma, reticular fiber staining should be selected. This type of staining is mostly based on silver impregnation and can highlight fine, highly branched reticular fiber structures.

1.2 Rapid selection pathway

 

 

2 PTAH Staining System

2.1 Staining positioning

(1) Striated muscle structure

PTAH, or phosphotungstic acid hematoxylin staining, can be used to display striations and myofibrillar structures in striated muscle. In myocardial and skeletal muscle samples, clear striations usually indicate good preservation of muscle fiber structure. If striations disappear, break, or stain unevenly, HE staining should be used to evaluate muscle fiber necrosis, degeneration, edema, and section orientation.

(2) Fibrin deposition

PTAH can stain fibrin blue or blue-purple, making it suitable for observing thrombi, fibrinous inflammation, exudates around necrotic foci, and intravascular deposits. Fibrin interpretation should be based on tissue location and morphology. When necessary, it should be combined with MSB staining or fibrin-related immunohistochemistry.

(3) Neuroglial fibers

In central nervous system tissue, PTAH can display neuroglial fibers and glial reaction-related structures. This method is suitable for morphological observation but cannot distinguish glial cell subtypes. If astrocytes, microglia, or oligodendrocytes need to be identified, immunomarkers such as GFAP, IBA1, and OLIG2 should be used.

2.2 Method characteristics

(1) Phosphotungstic acid-hematoxylin complex staining

In the PTAH system, phosphotungstic acid participates in both mordanting and differentiation and also affects dye retention by different protein structures. Target structures are usually blue to blue-purple, while the background may appear reddish-brown, brownish-yellow, or pale. The final result is strongly affected by stain maturation, oxidation state, and differentiation conditions.

(2) Sensitivity to fixation conditions

PTAH is sensitive to fixation methods. Insufficient fixation may lead to loose tissue structure and increased background. When fixation conditions vary greatly, the staining intensity of striated muscle, fibrin, and neuroglial fibers may be unstable. Positive controls should be included for retrospective paraffin samples.

(3) Suitable for structural indication, not single-target identification

PTAH can highlight certain proteinaceous structures, but it is not a molecular-specific assay. Blue staining does not necessarily indicate fibrin; it may also represent striated muscle or neuroglial fibers. Interpretation should be based on sample type and lesion location.

3 Masson Trichrome Staining System

3.1 Staining positioning

(1) Collagen fiber deposition

Masson trichrome staining is mainly used to distinguish collagen fibers, muscle fibers, and cytoplasm. Collagen is usually stained blue or green, muscle fibers and cytoplasm are stained red, and nuclei appear dark after nuclear staining. This system is suitable for analyzing liver fibrosis, pulmonary fibrosis, renal interstitial fibrosis, myocardial fibrosis, and skin scars.

(2) Evaluation of tissue remodeling

Masson staining not only displays collagen but also helps observe collagen distribution, deposition range, and the degree of tissue structural remodeling. For example, the scar area after myocardial infarction, destruction of hepatic lobular architecture, renal tubulointerstitial fibrosis, and thickening of alveolar septa can all be clearly evaluated using Masson staining.

(3) Animal models and pharmacodynamic evaluation

In fibrosis models, drug intervention models, and tissue injury repair experiments, Masson staining is commonly used for collagen area quantification. During image analysis, section thickness, staining conditions, imaging parameters, and threshold settings should be standardized to avoid batch effects affecting quantitative results.

3.2 Method characteristics

(1) Strong multicolor differentiation capability

Masson staining uses multiple staining and differentiation steps to create color contrast among collagen, muscle fibers, cytoplasm, and nuclei. Compared with simple collagen staining, it is more suitable for observing tissue structural relationships.

(2) Results are strongly affected by differentiation

Insufficient differentiation can blur the boundary between red and blue or red and green, reducing the contrast between collagen and muscle fibers. Over-differentiation may weaken collagen staining. Differentiation time and staining intensity should be optimized according to tissue type.

(3) Not suitable for displaying fine reticular fibers

Masson staining can display relatively coarse collagen deposition and fibrotic areas, but it is less sensitive than reticular fiber silver staining for fine reticular scaffolds. For analysis of hepatic plate scaffolds, bone marrow reticular structure, or lymphoid tissue framework, reticular fiber staining should be prioritized.

4 VG Staining System

4.1 Staining positioning

(1) Contrast between collagen and muscle

VG staining usually refers to Van Gieson staining. It commonly uses acid fuchsin and picric acid as the core components, staining collagen fibers red and muscle, cytoplasm, and part of the background yellow. Its advantage is a relatively concise system, suitable for rapid differentiation between collagen fibers and muscular tissue.

(2) Observation of scars and fibrosis

VG staining is suitable for observing scars, myocardial fibrosis, vascular wall collagen deposition, and connective tissue proliferation. Compared with Masson staining, VG has fewer color layers, but the contrast between collagen and muscle is direct, making it suitable for structural interpretation and rapid screening.

(3) Vascular wall and muscular tissue

In vascular, muscle, and myocardial samples, VG staining can highlight the difference between collagen and muscular components. If elastic laminae also need to be observed, elastic fiber staining should be added; VG should not be used to assess elastic fiber integrity.

4.2 Method characteristics

(1) Relatively simple operation

The VG workflow is usually simpler than Masson staining and is suitable for batch samples and rapid structural comparison. When collagen is clearly stained red, scar and collagen deposition areas can be intuitively displayed.

(2) Less information layering than Masson

VG mainly addresses the question of how to distinguish collagen from muscle/cytoplasm. It is less suitable than Masson for multilayered analysis of complex tissue remodeling. If comprehensive evaluation of collagen quantification, inflammatory background, and the relationship with muscle fibers is required, Masson usually provides richer information.

(3) Affected by picric acid background

In VG staining, picric acid stains muscle and background yellow. If differentiation, dehydration, or mounting conditions are unstable, the contrast between the yellow background and red collagen may be weakened. Color stability after long-term section storage also needs attention.

5 Elastic Fiber Staining Systems

5.1 Staining positioning

(1) Vascular elastic laminae

Elastic fiber staining is most commonly used to observe the internal and external elastic laminae of blood vessels. In arteriosclerosis, vasculitis, aneurysm, vascular remodeling, and vascular wall injury, rupture, thickening, curling, or disappearance of elastic laminae has important morphological significance.

(2) Elastic tissue in lung and skin

Elastic fibers in alveolar septa, dermal elastic fibers, and ligament elastic structures can all be observed using elastic fiber staining. This system has high application value in studies of chronic lung disease, skin aging, elastic fiber abnormalities, and connective tissue diseases.

(3) Tumor and tissue invasion boundaries

In some tumor tissues, elastic fiber staining can help identify vascular wall structures, serosal elastic layers, or tissue invasion boundaries. Interpretation should be combined with HE and immunohistochemistry results to avoid interpreting elastic fiber rupture alone as evidence of invasion.

5.2 Differences among common methods

(1) Verhoeff method

The Verhoeff method is commonly used to display coarse elastic fibers and vascular elastic laminae. Elastic fibers usually appear black or dark after staining. This method clearly demonstrates elastic layers in vascular walls and is suitable for analyzing arteries and large vessel structures.

(2) Weigert method

Weigert elastic fiber staining is suitable for displaying elastic fiber networks. Background control and differentiation conditions affect the result. When used for lung, skin, and vascular samples, differentiation strength should be adjusted according to elastic fiber thickness.

(3) Orcein method

The orcein method can be used to demonstrate elastic fibers and is commonly applied to skin, blood vessels, and some tissue sections. Its color tone is related to the specific formulation and counterstaining method. It is suitable for routine elastic fiber observation, but its performance for weak or fine elastic fibers should be validated.

(4) Victoria blue method

Victoria blue can display elastic fibers and is commonly used for analyzing blood vessels, lung, and tissue elastic structures. Compared with other elastic staining methods, its background and color tone are more dependent on stain condition, differentiation, and counterstaining combinations.

Table 1 Comparison of Elastic Fiber Staining Methods

Method	Main Target	Suitable Samples	Advantages	Notes
Verhoeff method	Coarse elastic fibers, vascular elastic laminae	Arteries, vascular walls, aneurysms	Clear elastic lamina outline	Over-differentiation may weaken elastic fiber staining
Weigert method	Elastic fiber networks	Lung, skin, blood vessels	Suitable for observing fiber network distribution	Background control and differentiation are critical
Orcein method	Elastic fibers and elastic tissue	Skin, blood vessels, connective tissue	Suitable for routine elastic fiber observation	Tissue background should be interpreted with counterstaining
Victoria blue method	Elastic fibers and elastic structures	Blood vessels, lung, selected tissue sections	Direct color display, suitable for structural observation	Stain condition and differentiation strongly affect results

6 Reticular Fiber Staining System

6.1 Staining positioning

(1) Display of tissue scaffold

Reticular fibers are mainly composed of type III collagen-related fibers and form fine, branching scaffolds. Reticular fiber staining usually uses silver impregnation, staining reticular fibers black or dark, and is suitable for observing hepatic lobular scaffolds, splenic cords, lymph node frameworks, bone marrow reticulum, and glandular stromal structures.

(2) Structural assessment of tumor tissue

In tumor pathology, reticular fiber staining can help observe tumor cell nests, stromal scaffolds, and tissue architectural destruction. For example, the distribution pattern of reticular fibers has reference value in hepatocellular carcinoma versus cirrhotic background, bone marrow fibrosis, and destruction of lymphoid tissue architecture.

(3) Bone marrow and hematopoietic tissue

Bone marrow reticular fiber staining is commonly used for evaluating bone marrow fibrosis. Increased, thickened, and interwoven reticular fibers can serve as important morphological indicators of bone marrow microenvironment remodeling. Results should be interpreted using a unified grading system rather than judged only by color intensity.

6.2 Method characteristics

(1) Silver impregnation is sensitive but technically demanding

Reticular fiber staining usually relies on silver salt deposition to display fine fiber structures. Silver impregnation is highly sensitive to slide cleanliness, oxidation, reduction, temperature, and time. Unstable operation may easily cause background deposition, discontinuous fibers, or whole-section blackening.

(2) Suitable for fine fibers, not equivalent to Masson staining

Masson staining displays collagen deposition and fibrosis range, whereas reticular fiber staining displays finer scaffold structures. Both are collagen-related, but the observed targets are different. For scaffold structure analysis in liver, bone marrow, spleen, and lymph nodes, reticular fiber staining is more targeted.

(3) Interpretation depends on tissue architecture

The significance of reticular fibers depends on tissue type. In liver tissue, attention is paid to hepatic plate scaffolds and fibrous septa. In bone marrow, fibrosis degree is assessed. In lymph nodes, scaffold integrity and architectural destruction are evaluated. In tumors, the scaffold pattern around cell nests is important.

7 Method Combinations in Different Research Scenarios

7.1 Fibrosis research

(1) Collagen deposition as the main focus

In liver fibrosis, pulmonary fibrosis, renal interstitial fibrosis, and myocardial fibrosis research, Masson staining is a common first choice. If rapid confirmation of collagen versus muscle background is required, VG staining can also be used as an auxiliary method.

(2) Scaffold structure as the main focus

If hepatic plate architecture, bone marrow fibrosis, or lymphoid tissue scaffold is being studied, reticular fiber staining is more suitable than Masson. Masson can display fibrosis range but cannot fully replace the fine scaffold information provided by reticular fiber silver staining.

7.2 Vascular and elastic tissue research

(1) Vascular wall structure

Vascular lesion studies should prioritize elastic fiber staining to observe the internal elastic lamina, external elastic lamina, elastic fiber rupture, and vascular wall remodeling. If collagen deposition is also a concern, Masson or VG staining can be combined.

(2) Elastic tissue in lung and skin

For pulmonary elastic fiber remodeling, dermal elastic fiber changes, and connective tissue disease research, elastic fiber staining is more targeted than Masson and VG. If collagen proliferation also needs to be evaluated, Masson staining can be combined.

7.3 Muscle and thrombus research

(1) Striated muscle structure

PTAH is preferred for displaying striations in myocardium and skeletal muscle. If myocardial fibrosis is being studied, Masson or VG is more suitable. If both muscle fiber structural disruption and fibrosis are being analyzed, PTAH should be combined with Masson.

(2) Thrombus and fibrin

PTAH can be used to display fibrin-like structures, but when thrombus composition is complex, MSB or immunohistochemistry usually provides more information. PTAH is suitable for auxiliary morphological confirmation and should not be used alone for thrombus component stratification.

Table 2 Typical Experimental Purposes and Special Staining Combinations

Experimental Purpose	Recommended Staining Combination	Main Interpretation Content
Liver fibrosis evaluation	Masson + reticular fiber staining	Collagen deposition range and hepatic plate scaffold changes
Myocardial injury and fibrosis	PTAH + Masson/VG	Preservation of muscle striations and formation of collagen scar
Vascular remodeling	Elastic fiber staining + Masson/VG	Elastic lamina rupture and collagen deposition
Bone marrow fibrosis	Reticular fiber staining	Bone marrow reticular fiber proliferation and grading
Thrombus structure analysis	PTAH + MSB/IHC	Fibrin distribution and thrombus component confirmation
Skin elastic tissue changes	Elastic fiber staining + Masson	Elastic fiber changes and collagen remodeling

8 Method Boundaries and Common Failure Causes

8.1 Method boundaries

(1) PTAH cannot replace fibrin immunohistochemistry

PTAH can display fibrin-like structures, but it does not have antibody-based molecular specificity. If the research focus is fibrin or fibrinogen localization, immunohistochemistry should be combined.

(2) Masson and VG cannot replace reticular fiber staining

Masson and VG are suitable for contrasting collagen with muscle background, but they cannot fully display fine reticular scaffolds. Silver impregnation should be used for reticular fiber structural analysis.

(3) Elastic fiber staining cannot be replaced by collagen staining

Elastic fibers and collagen fibers differ in structure, distribution, and pathological significance. Elastic lamina rupture in vessels, abnormal pulmonary elastic structures, and dermal elastic fiber changes should be examined using elastic fiber staining rather than relying only on Masson or VG.

8.2 Common failure causes

Table 3 Common Problems and Optimization Directions in Classical Special Staining

Problem	Possible Cause	Staining Involved	Optimization Direction
Weak blue staining of PTAH target structures	Insufficient stain maturation, over-differentiation, unsuitable fixation	PTAH	Set positive controls, adjust differentiation time, check stain condition
Unclear boundary between collagen and muscle in Masson staining	Insufficient differentiation, inappropriate staining time	Masson	Optimize differentiation steps and standardize section thickness
Weak red collagen staining in VG	Decreased stain potency, excessive dehydration, or improper differentiation	VG	Check acid fuchsin solution and shorten excessive processing steps
Elastic fibers appear discontinuous or too pale	Over-differentiation, aged stain, poor fixation	Elastic fiber staining	Shorten differentiation, renew stain, use positive vascular tissue control
Whole reticular fiber section turns black	Excessive silver impregnation, slide contamination, excessive reduction	Reticular fiber staining	Control silver staining time, use clean slides, optimize reduction step
Obvious batch-to-batch variation	Inconsistent stain batches, temperature, time, or differentiation	All special stains	Standardize workflow parameters and include positive controls in each batch

9 Product Selection for Classical Histological Special Staining

Table 4 Basic Chemical Reagents and Key Dyes for Classical Histological Special Staining

Method System	Product/Reagent Name	CAS No.	Product Category	Application Positioning
PTAH staining	Hematoxylin	517-28-2	Special staining dye	Core dye in PTAH system; also used in HE, Weigert iron hematoxylin, and related staining systems
PTAH staining	Phosphotungstic acid hydrate	12501-23-4	Mordant/differentiation-related reagent	Key component of PTAH system; participates in phosphotungstic acid-hematoxylin complex staining and selective structural retention
Masson trichrome staining	Acid Red 66 / Biebrich Scarlet	4196-99-0	Acid red dye	Used in Masson-type systems to stain cytoplasm, muscle fibers, and erythrocytes red
Masson trichrome staining	Acid fuchsin	3244-88-0	Acid dye	Used for collagen/muscle background counterstaining and as a red staining component in Masson-related systems
Masson trichrome staining	Aniline blue	28631-66-5	Collagen staining dye	Used to stain collagen fibers blue; suitable for fibrosis and tissue remodeling observation
Masson trichrome staining	Light Green SF Yellowish	5141-20-8	Collagen staining dye	Used for collagen fiber green staining in light green-type Masson systems
Masson trichrome staining	Fast Green FCF	2353-45-9	Acid dye	Used in collagen or background structure staining system development
VG staining	Acid fuchsin	3244-88-0	Acid dye	Used in VG system to stain collagen fibers red
Elastic fiber staining	Orcein	1400-62-0	Elastic fiber dye	Used in orcein elastic fiber staining
Elastic fiber staining	Basic fuchsin	632-99-5	Basic dye	Used in resorcin-fuchsin-type elastic fiber staining systems
Elastic fiber staining	Victoria Blue B	2580-56-5	Elastic fiber dye	Used in Victoria blue method for demonstrating elastic fibers and elastic structures
Reticular fiber staining	Silver nitrate	7761-88-8	Silver impregnation reagent	Core reagent for reticular fiber silver staining, used to visualize fine reticular scaffolds
Reticular fiber staining	Chloroauric acid trihydrate	16961-25-4	Toning reagent	Used for post-silver staining toning to improve reticular fiber contrast and stability
Reticular fiber staining	Sodium thiosulfate	7772-98-7	Fixing reagent	Used after silver staining to fix the reaction and reduce nonspecific silver deposition
Reticular fiber staining	Nuclear Fast Red	6409-77-4	Counterstain	Used for nuclear or background counterstaining after reticular fiber silver staining

Table 5 Selection of Ready-to-Use Products and Method Systems for Classical Histological Special Staining

Method System	Cat. No.	Product Name	Grade/Specification	Product Category	Application Positioning
PTAH staining	M1516033	Mallory PTAH Stain Solution (Spontaneous Oxidation Method)	BioReagent,Biological dye grade,for microscopy	PTAH staining solution	Used to display striated muscle striations, fibrin, neuroglial fibers, and related structures; suitable for natural oxidation PTAH workflow
PTAH staining	M1518515	Mallory Phosphotungstic Acid Hematoxylin Staining Solution (PTAH Natural Oxidation Method)	BioReagent,Biological Stain,for microscopy	PTAH staining solution	Used for phosphotungstic acid hematoxylin natural oxidation staining; suitable for observing muscle fibers, fibrin, and glial fibers
PTAH staining	M774799	Mallory's Phosphotungstic Acid Hematoxylin Staining Kit (PTAH Chemical Oxidation)	BioReagent, Biological Stain, for microscopy	PTAH staining kit	Used for PTAH chemical oxidation staining; suitable for standardized display of striated muscle, fibrin, and glial fibers
Masson trichrome staining	M774209	Masson's Trichrome Staining Kit	BioReagent, Biological Stain, for microscopy	Masson staining kit	Used for multicolor differentiation of collagen fibers, muscle fibers, and cytoplasm; suitable for fibrosis and tissue remodeling evaluation
Masson trichrome staining	M774803	Masson Trichrome Staining Kit (Fast Green Method)	BioReagent, Biological Stain, for microscopy	Masson light green method kit	Used for light green-type Masson staining; suitable for collagen fiber green staining and fibrosis range analysis
Masson trichrome staining	I774801	Modified Masson Trichrome Staining Solution	BioReagent, Biological Stain, for microscopy	Modified Masson staining solution	Used for observing collagen deposition, muscle fibers, and tissue remodeling; suitable for routine histological special staining workflows
VG staining	V774853	Van Gieson Staining Solution	BioReagent, Biological Stain, for microscopy	VG staining solution	Used for rapid contrast between collagen fibers and muscle/cytoplasmic background
VG staining	V774854	Van Gieson Staining Kit	BioReagent, Biological Stain, for microscopy	VG staining kit	Used to stain collagen red and muscle/cytoplasmic background yellow; suitable for observing scars, myocardium, and vascular wall collagen
VG staining	I774852	Modified Van Gieson Staining Solution	BioReagent, Biological Stain, for microscopy	Modified VG staining solution	Used for rapid differentiation between collagen and muscular tissue; suitable for routine fibrosis and connective tissue proliferation observation
VG staining / nuclear stain support	W774793	Weigert's Hematoxylin Staining Kit	BioReagent, Biological Stain, for microscopy	Iron hematoxylin nuclear staining kit	Commonly used as acid-resistant nuclear staining before VG, elastic fiber, and other acidic staining systems
Elastic fiber staining	V774847	Verhoeff Elastic Fiber Staining Kit	BioReagent, Biological Stain, for microscopy	Verhoeff elastic fiber staining kit	Used to observe vascular elastic laminae, coarse elastic fibers, and arterial wall structures
Elastic fiber staining	V1518609	Verhöeff Elastic Fiber Staining Solution (Eosin Counterstain)	BioReagent,Biological Stain,for microscopy	Verhoeff elastic fiber staining solution	Used for Verhoeff elastic fiber display, with eosin counterstaining to enhance tissue background contrast
Elastic fiber staining	V1518552	Verhöeff Elastic Fiber Staining Solution (Orange G Counterstain)	BioReagent,Biological Stain,for microscopy	Verhoeff elastic fiber staining solution	Used for Verhoeff elastic fiber display, with orange counterstaining to distinguish tissue background
Elastic fiber staining	W774848	Weigert Elastic Fiber Staining Kit	BioReagent, Biological Stain, for microscopy	Weigert elastic fiber staining kit	Used to display elastic fiber networks in blood vessels, lung, skin, and related tissues
Elastic fiber staining	L1518590	Lichen Red Elastic Fiber Staining Solution	BioReagent,Biological Stain,for microscopy	Orcein elastic fiber staining solution	Used to display elastic fibers in skin, blood vessels, and connective tissue
Elastic fiber staining	V774850	Victoria Blue Elastic Fiber Staining Kit	BioReagent, Biological Stain, for microscopy	Victoria blue elastic fiber staining kit	Used to observe elastic fibers and elastic structures in blood vessels, lung, and tissues
Reticular fiber staining	M774808	Reticular Fibre Staining Solution (Gomori)	BioReagent, Biological Stain, for microscopy	Reticular fiber silver staining solution	Used to display reticular fiber scaffolds in liver, spleen, bone marrow, lymph nodes, and tumor stroma
Reticular fiber staining	M774851	Reticular Fibre Staining Solution (Gordon-Sweets)	BioReagent, for microscopy, Biological Stain	Reticular fiber silver staining solution	Used to display fine reticular fibers, tissue scaffolds, and bone marrow fibrosis-related structures

10 Common Questions

10.1 Should Masson or VG be selected for fibrosis research?

Masson is more suitable for evaluating fibrosis range and tissue remodeling. It provides richer color layering and is commonly used for image quantification. VG is more suitable for rapid contrast between collagen and muscle background and has a relatively simple workflow. If collagen area quantification is required, Masson is generally more commonly used.

10.2 Can PTAH be used for collagen fiber staining?

PTAH is not recommended as the first choice for collagen fiber staining. It is more suitable for displaying striated muscle striations, fibrin, and glial fibers. Collagen deposition and fibrosis evaluation should prioritize Masson or VG staining.

10.3 What is the difference between elastic fiber staining and Masson staining?

Elastic fiber staining displays elastic fibers and elastic laminae and is suitable for analyzing elastic structures in blood vessels, lung, and skin. Masson staining displays collagen fibers and fibrosis range. The two methods target different structures and cannot replace each other.

10.4 Can both reticular fiber staining and Masson staining be used to observe fibrosis?

They have different emphases. Masson displays prominent collagen deposition and fibrosis range, while reticular fiber staining displays fine scaffold structures. For scaffold analysis in liver, bone marrow, spleen, and lymph nodes, reticular fiber staining is more valuable.

10.5 Which special staining should be selected for vascular lesions?

If the focus is rupture, curling, or disappearance of elastic laminae, elastic fiber staining should be selected. If the focus is collagen deposition and fibrosis in the vascular wall, Masson or VG can be combined. If the focus is thrombus fibrin, PTAH or MSB staining can be added.

10.6 Why are positive controls necessary for special staining?

Special staining is highly dependent on stain condition, fixation method, differentiation, and operation time. Positive controls can confirm whether the staining system is valid and prevent technical failure from being misinterpreted as negativity or reduction of the target structure.

The selection of classical special staining should be based on the target structure. PTAH is used for striated muscle, fibrin, and glial fibers. Masson and VG are used for collagen and fibrosis. Elastic fiber staining is used for vascular and elastic structures. Reticular fiber staining is used for tissue scaffolds. Defining method boundaries and including positive controls are essential for obtaining reliable results.

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