Diagnostic Utility

As vimentin expression has been detected in an ever-expanding number of neoplasms, its diagnostic utility has progressively lessened. In distinguishing between undifferentiated carcinomas and melanomas, strong vimentin expression may favor melanoma. However, this distinction is made much more easily and directly with use of the relatively melanocyte-specific markers such as MART-1, HMB-45 or tyrosinase (see Chapter 6).

In the more subtle distinction of spindle cell neoplasms in the skin, vimentin is similarly limited. All mesenchymally derived neoplasms such as leiomyosarcomas, dermatofibrosarcoma protuberans, glo-mus tumors, and atypical fibroxanthomas express vimentin (Fig. 1) (8,9). Further, endothelial cell derived tumors (also mesenschymal) express this protein. Thus, vimentin expression does nothing to dis-

Fig. 1. Vimentin is expressed strongly by most mesenchymally derived neoplasms. Note also the strong staining of Langerhans cells and melanocytes within the epidermis by anti-vimentin antibodies.

criminate between these neoplasms. Further exacerbating the problem is the relatively newer finding that squamous cell carcinomas with a spindle-shaped morphology can be expected to express vimentin, as can spindle cell melanomas (10,11). In one series, 40% of spindle cell squamous cell carcinomas expressed vimentin (12). Thus, virtually every neoplasm occurring within the skin that may demonstrate a spindle cell morphology would likely be detected by anti-vimentin antibodies.

Rare cutaneous neoplasms with a more epithelial morphology, such as lymphoepithelioma-like carcinomas, lymphadenomas and rhabdoid tumors may also display vimentin filaments in the epithelial components (13-15).

In the work-up of metastatic neoplasms involving the skin, vimentin positivity must be interpreted with caution, as renal cell carcinomas, endometrial adenocarcinomas, thyroid carcinomas, adrenocortical adenomas, adenocarcinomas of the lungs, ovaries, salivary glands, prostate, and breast have all been shown to express vimentin (12).

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How To Prevent Skin Cancer

How To Prevent Skin Cancer

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