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Published on: June 7, 2019
PRAME Expression in Recurrent/Persistent Melanocytic Nevi
Alison H Kucharik1, Helana Ghali2, Doniya Milani1,3
1Department of Dermatology and Cutaneous Surgery, University of South Florida, Tampa, FL.
Background:
Recurrent melanocytic nevi are benign melanocytic proliferations that occur after incomplete excision of a nevus. Their atypical clinical and histopathologic features complicate diagnosis, especially without knowledge of prior biopsy. The PRAME (PReferentially expressed Antigen in MElanoma) immunohistochemical stain has been increasingly used to support a diagnosis of melanoma, however, its utility in recurrent melanocytic nevi is not well established.
Methods:
We analyzed PRAME expression in paired original and recurrent melanocytic nevi from 22 patients. Tissue sections underwent PRAME immunohistochemistry, evaluated by 2 dermatopathologists using 3 criteria: (1) staining intensity, (2) percentage of melanocytes with nuclear staining, and (3) a composite score.
Results:
Among original nevi, 81.8% had an intensity score of 0, 9.1% scored 1, 4.5% scored 2%, and 4.5% scored 3. Percentage positivity was 81.8% at score 0 and 18.2% at score 1. All had a negative composite score. Recurrent nevi showed similar results, with 81.8% intensity score 0, 9.1% score 1, 4.5% score 2, and 4.5% score 3. Percentage positivity was 81.8% at score 0 and 18.2% at score 1, with all patients scoring negative on the composite score.
Conclusions:
PRAME expression remained consistent between original and recurrent nevi, with all patients showing negative composite scores. These findings support PRAME's utility in differentiating benign recurrent nevi from melanoma, even when histologic or clinical features raise concern. PRAME staining may enhance diagnostic confidence, reducing unnecessary procedures.
Insights
PRAME immunohistochemistry is useful for diagnosing recurrent melanocytic nevi. This stain helps differentiate benign nevi from melanoma, improving diagnostic confidence and potentially reducing unnecessary procedures.
Area of Science:
- Dermatopathology
- Immunohistochemistry
- Oncology
Background:
- Recurrent melanocytic nevi can present with atypical features, complicating diagnosis, especially without prior biopsy information.
- The PReferentially expressed Antigen in MElanoma (PRAME) stain is used for melanoma diagnosis, but its role in recurrent nevi is unclear.
Purpose of the Study:
- To evaluate the utility of PRAME immunohistochemistry in distinguishing benign recurrent melanocytic nevi from melanoma.
- To assess PRAME expression consistency between original and recurrent nevi.
Main Methods:
- Analyzed PRAME expression in paired original and recurrent melanocytic nevi from 22 patients.
- Evaluated PRAME immunohistochemistry using staining intensity, percentage of positive melanocytes, and a composite score.
Main Results:
- PRAME expression patterns were consistent between original and recurrent nevi.
- All analyzed cases, both original and recurrent nevi, showed negative composite scores for PRAME staining.
Conclusions:
- PRAME immunohistochemistry demonstrates utility in differentiating benign recurrent nevi from melanoma.
- Consistent negative PRAME composite scores in recurrent nevi enhance diagnostic confidence and may help avoid unnecessary procedures.
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