Colloid Gallery - A Gallery of Colloid

Colloid is commonly present on ThinPrep^® prepared slides of thyroid fine-needle aspirates. Abundant colloid is a feature of benign follicular thyroid lesions, while scant colloid raises suspicion for malignancy. Ultimately, however, nuclear features and architecture are the criteria used to diagnose malignant lesions. Diagnostic Cytopathology, Volume 30, Number 1, January 2004, pages 7-13, contains a helpful article by Mark A. Tulecke and Helen H. Wang, entitled “ThinPrep^® for Cytologic Evaluation of Follicular Thyroid Lesions: Correlation With Histologic Findings”. The varying appearances of colloid are pictured and described in the article.

To further assist in the identification of colloid, a gallery illustrating different morphologic appearances of colloid has been created for use as a reference guide. Additional photographs may be added as cases are collected.

The following pictures are from benign thyroid lesions:

Reminder: You may click on any slide image
for an enlarged view.

Cyanophilic staining fragment of colloid with frayed edges.
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Cyanophilic staining fragment of colloid with frayed edges.
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Cyanophilic staining fragment of colloid adjacent to a macrophage containing hemosiderin, red blood cells, and ingested colloid from a cystic lesion.
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Cyanophilic staining fragment of colloid adjacent to a macrophage containing hemosiderin, red blood cells, and ingested colloid from a cystic lesion.
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Eosinophilic staining colloid with frayed edges.
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Eosinophilic staining colloid with frayed edges.
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Shiny, refractile colloid in a background of proteinaceous debris.
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Shiny, refractile colloid in a background of proteinaceous debris.
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Colloid surrounded by follicular cells exhibiting Hürthle cell change. Lysed blood is in the background.
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Colloid surrounded by follicular cells exhibiting Hürthle cell change. Lysed blood is in the background.
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A large, dense fragment of bichromatic staining colloid. Small follicular cells and proteinaceaous debris are in the background.
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A large, dense fragment of bichromatic staining colloid. Small follicular cells and proteinaceaous debris are in the background.
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“Cracked” edges of a dense colloid fragment adjacent to benign follicular cells.
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“Cracked” edges of a dense colloid fragment adjacent to benign follicular cells.
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“Tissue-paper” colloid as described by Tulecke and Wang.
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“Tissue-paper” colloid as described by Tulecke and Wang.
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Dense, bichromatic staining colloid.
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Dense, bichromatic staining colloid.
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“Tissue-paper” colloid representing watery colloid as described by Tulecke and Wang.
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“Tissue-paper” colloid representing watery colloid as described by Tulecke and Wang.
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Droplets of colloid of varying size interspersed among benign follicular cells.
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Droplets of colloid of varying size interspersed among benign follicular cells.
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Stringy, shiny colloid as a component of a benign aspirate.
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Stringy, shiny colloid as a component of a benign aspirate.
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Magnified view of watery colloid.
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Magnified view of watery colloid.
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Large fragment of eosinophilic staining colloid with varying size droplets intermixed with follicular cells and debris.
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Large fragment of eosinophilic staining colloid with varying size droplets intermixed with follicular cells and debris.
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Colloid admixed with benign follicular cells.
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Colloid admixed with benign follicular cells.
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Well-formed colloid is seen within an intact follicle.
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Well-formed colloid is seen within an intact follicle.
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Eosinophilic staining colloid with histiocytes in the background.
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Eosinophilic staining colloid with histiocytes in the background.
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Fragments of colloid are easily recognized at screening power.
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Fragments of colloid are easily recognized at screening power.
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Is this colloid, or something mimicking colloid?
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Is this colloid, or something mimicking colloid?
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Changing the focal plane reveals that this is not colloid, but an orangeophilic stained, degenerating squamous cell, a colloid “look-alike”. Note the smooth edges and polygonal shape of a typical squamous cell.
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Changing the focal plane reveals that this is not colloid, but an orangeophilic stained, degenerating squamous cell, a colloid “look-alike”. Note the smooth edges and polygonal shape of a typical squamous cell.
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The following pictures are from malignant thyroid lesions:

Colloid associated with malignant lesions is usually dense, the so called “sticky colloid”.

Colloid accompanying a case of medullary carcinoma.
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Colloid accompanying a case of medullary carcinoma.
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Colloid associated with a case of papillary carcinoma.
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Colloid associated with a case of papillary carcinoma.
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Colloid associated with an additional case of papillary carcinoma.
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Colloid associated with an additional case of papillary carcinoma.
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Additional References

1. Afify AM, Liu J, Al-Khafaji BM: Cytologic artifacts and pitfalls of thyroid fine-needle aspiration using ThinPrep. Cancer (Cancer Cytopathology) 2001;93(3):179-86.
2. Biscotti CV, Shorie JH, Gramlich TL, Easley KA: ThinPrep vs. conventional smear cytologic preparations in the analysis of thyroid fine-needle aspirations specimens. Am J Clin Pathol 995; 104(2):150-3.
3. Cheung CC, Carydis B, Ezzet S, Bedard YC, AsaSL: Analysis of ret/PTC gene rearrangement refines the fine needle aspiration diagnosis of thyroid cancer. J Clin Endocrinol Metab 2001; 86(5):2187-90.
4. Frost AR, Sidawy MK, Ferfelli M et al: Utility of thin-layer preparations in thyroid fine-needle aspiration: Diagnostic accuracy, cytomorphology, and optimal sample preparation. Cancer (Cancer Cytopathol) 998; 84:17-25.
5. Scurry JP, Duggan MA: Thin layer compared to direct smear in thyroid fine needle aspiration. Cytopathology 2000; 11:104-115.
6. Zhang Y, Fraser JL, Wang HH: Morphologic predictors of papillary carcinoma on fine-needle aspiration of thyroid with ThinPrep preparations. Diagn Cytopathol 2001; 24(6):378-83.

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