AMP case report: aCGH as a diagnostic aid in a childhood Spitzoid melanoma

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Conclusion
Melanomas in children are rare. When presented with atypical Spitzoid melanocytic proliferations in children, utmost caution has to be exercised when distinguishing between a SN, AST, and SMM. This case demonstrates how aCGH was pivotal in resolving a diagnostic dilemma with important clinical implications and highlights the utility of molecular diagnostic techniques as adjuncts to diagnosis in clinicopathologically ambiguous melanocytic neoplasms.

References

1. Barnhill RL, Cerroni L, Cook M, et al. State of the art, nomenclature, and points of consensus and controversy concerning benign melanocytic lesions: outcome of an international workshop. Adv Anat Pathol 2010;17:73.
2. Barnhill RL. The Spitzoid lesion: rethinking Spitz tumors, atypical variants, ‘Spitzoid melanoma’ and risk assessment. Mod Pathol 2006;19(suppl 2): S21–33.
3. Al Dhaybi R, Agoumi M, Gagne I, et al. p16 expression: a marker of differentiation between childhood malignant melanomas and Spitz nevi. J Am Acad Dermatol 2011;65(2):357–363.
4. Mason A, Wittitsuwannakul J, Klump VR, et al. Expression of p16 alone does not differentiate between Spitz nevi and Spitzoid melanoma. J Cutan Pathol 2012; 39:1062–1074.
5. Vollmer RT. Use of Bayes rule and MIB-1 proliferation index to discriminate Spitz nevus from malignant melanoma. Am J Clin Pathol 2004;122:499–505.
6. Prieto VG, Shea CR. Immunohistochemistry of melanocytic proliferations. Arch Pathol Lab Med 2011;135:853–859.
7. Gerami P, Zembowicz A. Update on fluorescence in situ hybridization in melanoma: state of the art. Arch Pathol Lab Med 2011;135:830–837.
8. Bastian BC, LeBoit PE, Hamm H, et al. Chromosomal gains and losses in primary cutaneous melanomas detected by comparative genomic hybridization. Cancer Res 1998;58:2170–2175.
9. McCalmont TH, Vemula S, Sands P, Bastian BC. Molecular-microscopical correlation in dermatopathology. J Cutan Pathol 2011;38(4):324–326.
10. Pinkel D, Albertson DG. Array comparative genomic hybridization and its applications in cancer. Nature Genetics 2005;37:S11–S17.

Drs. Danialan, Gopinath, Ricci, Earle, and Elaba are in the Department of Pathology, Hartford (Conn.) Hospital. Dr. Murphy is in the Department of Dermatology and Dermatopathology, University of Connecticut. Dr. Rader is in the Department of Surgery, Connecticut Children’s Medical Center, Hartford.

Test yourself: Here are three questions taken from the case report.

Answers are online now at www.amp.org/casereports and will be published next month in CAP TODAY.

1. Which of the following ancillary techniques is (are) used in the diagnosis of melanoma?

A. Immunohistochemistry (IHC)
B. Fluorescence in situ hybridization (FISH)
C. Array comparative genomic hybridization (aCGH)
D. All of the above
E. None of the above

2. Which of the following genetic
abnormalities supports a diagnosis of melanoma?

A. CDKN2A (p16 gene) mutations
B. Multiple chromosomal gains and losses
C. BRAF (V600E) mutations
D. GNAQ mutations
E. All of the above

3. True or false: The finding of deleterious CDKN2A (p16) mutations in melanoma tumor cells is an indication of Familial Atypical Multiple Mole Melanoma (FAMMM) syndrome.

Last month’s answers

Answers to the August case report questions on Lynch syndrome and endometrial carcinoma.

1. What is the mode of inheritance for Lynch syndrome?
C. Autosomal dominant

2. What is the expected IHC pattern associated with a genetic defect in MSH6?
D. MSH6 (−) / MSH2 (+)

3. What is the most common cause of microsatellite instability (MSI) in endometrial carcinoma?
A. MLH1 promoter methylation