Langerhans cell histiocytosis of solitary inguinal mass: Diagnosis and treatment of an unusual case with complete response

Langerhans cell histiocytosis (LCH) is a “histiocytic” disorder with a spectrum of presentations often with different names having confined a bone, overlying skin, and local lymph nodes or having multiorgan involvement. It is characterized by clonal proliferation of Langerhans cells, which have typical grooved nuclei and tennis racquet-shaped Birbeck’s granules. It is more common in children below 10 years. It is more common in men with M:F is 2:1. Bone is the most common site of involvement. Among lymph nodes, cervical chain is most commonly involved and inguinal lymphatic chain involvement is rarely seen. Diagnosis requires histopathological confirmation. Histopathology shows proliferation of dendritic cells expressing high levels of Langerin, a lectin required for the formation of Birbeck granules. It is positive for CD1a, Langerin, S100, CD68, and vimentin. Here, we are reporting a case of LCH of solitary inguinal mass, localized to unilateral pubic bone, overlying skin and inguinal nodes, in a 35-year-old man. Our aim is to discuss about the investigations leading to diagnosis of this rare entity, LCH; its treatment with surgery and adjuvant radiotherapy, which led to complete response and patient is disease free even after 4 years of treatment.