FNA diagnosis of primary adult onset lymphocutaneous Langerhans' cell histiocytosis masquerading as deep fungal mycosis.

Langerhans' cell histiocytosis (LCH) in its aggressive disseminated form seen most often in children is easily diagnosed by the treating physician. On the contrary, LCH in an adult is localized, extremely rare, and, hence, its diagnosis is missed quite often or underdiagnosed. We describe the troubleshooters encountered in the fine-needle aspiration (FNA) diagnosis of LCH in an adult who presented for 4 years with ulceronodular lesions over the neck, both axillae, and inguinal regions since 4 years of age, which had closely mimicked deep mycosis both clinically and histopathologically.