Vimentin

• Vimentin staining histiocytes in xanthogranulomatous inflammation.
• Vimentin expression in a cardiac myosarcoma. Vimentin is NOT a specific marker for mesenchymal tumors.
• Vimentin expression in a cardiac myosarcoma. Vimentin is NOT a specific marker for mesenchymal tumors.
• Vimentin expression in a cellular blue nevus.

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Vimentin is one of the 5 major intermediate filaments found in cells (cytokeratin, vimentin, neurofilament, desmin, and glial fibrillary acid protein [GFAP]). It was classically thought to be limited to mesenchymal cells only, and in the early days of immunohistochemistry, it was thought to be a specific marker for sarcomas and other mesenchymal neoplasms. Newer articles have soundly refuted this idea by showing that vimentin is positive in many types of carcinomas and other non-mesenchymal cells. However, many pathologist continue to use vimentin on a regular basis, although the stain provides them with little to no useful information.

Here is a brief video regarding the appropriate utilization and interpretation of vimentin staining (note: it is intended to be an exaggeration for the intent of humor, but also to teach a valuable lesson): Vimentin Video

Staining Pattern

• Cytoplasmic

Expression in Neoplastic Entities

Malignant

• Sarcoma (most types)
• Lymphoma
• Melanoma
• Renal Cell Carcinoma
• Some Adenocarcinomas
• Thyroid Carcinoma
• Sarcomatoid Carcinoma
• Squamous cell carcinoma

Benign

• Peripheral Nerve Sheath Tumors (e.g. - schwannoma)
• Glomus tumor

Practical Uses / Panels

• Some advocate the use of vimentin to determine if a tissue sample has lost its antigenicity (and thus, other negative immunostains on that tissue should not be considered as true negatives). Thus, if vimentin is totally negative in a tissue, then it is likely that the antigens are no longer viable and other immunos will not likely work. If vimentin is positive, however, it does not guarantee that other antigens are preserved. As an intermediate filament, vimentin is quite durable and can persist even after cell death in some cases.

Common Pitfalls

• If vimentin is positive, it does NOT mean that a neoplasm is definitely mesenchymal. It is not specific to mesenchymal cells.