Cutaneous balloon-cell melanoma metastases to the axillary lymph node: Exploring cytomorphologic features and differential diagnoses on fine needle aspiration biopsy.

Abstract

Balloon cell melanoma (BCM) is an exceptionally uncommon histological variant, making up <1% of all malignant melanomas. Diagnosing balloon cell melanoma on cytological specimens can be challenging due to its scarcity and its similarity to other medical conditions. A comprehensive clinical assessment and histological analysis, coupled with immunohistochemical staining, play a crucial role in distinguishing balloon cell melanoma from various benign and malignant skin conditions. The differential diagnoses encompass spitz nevus, balloon cell nevus, clear cell sarcoma of tendons and aponeuroses (melanoma of soft tissues), metastatic clear cell renal cell carcinoma, sebaceous carcinoma, and benign adnexal tumours like clear cell hidradenoma. Malignant melanoma encompasses a spectrum of histopathological subtypes, each with unique clinical and cytological characteristics. Notably, balloon-cell melanoma (BCM) emerges as an exceptionally rare and diagnostically challenging variant. Marked by the presence of distinct balloon-like, clear cytoplasmic vacuoles within melanoma cells, BCM stands apart from other melanoma subtypes. Despite its rarity, the distinctive cytological features of BCM make it a compelling subject of investigation, emphasizing the crucial role of Fine Needle Aspiration (FNA) cytology in ensuring accurate diagnosis and guiding subsequent management decisions.