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Atypical Spitz Tumors: A Diagnostic Challenge.
Kelly L Harms1, Lori Lowe, Douglas R Fullen
1From the Department of Dermatology (Drs K. L. Harms, Lowe, Fullen, and P. W. Harms), the Comprehensive Cancer Center (Dr K. L. Harms), and the Department of Dermatology and Pathology (Drs Lowe, Fullen, and P. W. Harms), University of Michigan Medical School, Ann Arbor.
Atypical Spitz tumors are challenging borderline lesions with uncertain malignant potential. While they frequently involve lymph nodes and show chromosomal changes, most cases exhibit an indolent course, indicating a need for careful evaluation.
Area of Science:
- Dermatopathology
- Oncology
- Molecular Pathology
Background:
- Spitzoid melanocytic lesions range from benign Spitz nevi to malignant spitzoid melanomas.
- Spitzoid neoplasms possess distinct morphologic and molecular characteristics compared to conventional melanocytic lesions.
- Predicting biologic behavior and metastatic risk in spitzoid neoplasms can be challenging.
Purpose of the Study:
- To review the clinical, microscopic, and molecular features of atypical Spitz tumors.
- To highlight recent molecular advances and their prognostic significance.
- To discuss the diagnostic challenges posed by these borderline lesions.
Main Methods:
- Review of clinical presentations of atypical Spitz tumors.
- Analysis of characteristic histologic features under microscopy.
- Examination of molecular alterations, including chromosomal copy number changes and gene mutations.
- Correlation of molecular findings with clinical behavior and patient outcomes.
Main Results:
- Atypical Spitz tumors are characterized by overlapping histologic features with Spitz nevi and spitzoid melanomas.
- These lesions frequently involve sentinel lymph nodes and exhibit chromosomal copy number alterations.
- Despite frequent genetic abnormalities, the majority of atypical Spitz tumors follow an indolent clinical course.
- Homozygous CDKN2A loss is a notable chromosomal abnormality with potential prognostic implications.
Conclusions:
- Atypical Spitz tumors represent a distinct entity within the spitzoid neoplasm spectrum, posing diagnostic and prognostic challenges.
- Understanding the molecular landscape, including chromosomal abnormalities like CDKN2A loss, is crucial for risk stratification.
- Further research is needed to refine diagnostic criteria and therapeutic strategies for atypical Spitz tumors.
