Metastatic Intraparotid Balloon Cell Melanoma: A Diagnostic Challenge.

BACKGROUND

BCM is an uncommon cytomorphologic variant with the potential to mimic unrelated neoplastic conditions, especially in the absence of a known cutaneous primary lesion or limited access to immunohistochemical stains.

CASE PRESENTATION: A 28-year-old male patient presented with recent onset parotid gland mass. The mass was excised, and the subsequent workup elicited an interpretation of metastatic balloon cell melanoma (BCM). Despite an extensive evaluation, no evidence of a primary tumor site was identified.

DIAGNOSIS: The diagnosis was confirmed based on positive staining for BRAF, HMB45, Melan-A, PRAME, S100, and SOX-10 in the malignant cells.

CONCLUSION

Familiarity with the histologic and immunophenotypic findings may help to ensure an accurate diagnosis.