Primary Langerhans Cell Histiocytosis of the Maxilla: Case Report.

A 5-year-old boy presented with a two-month history of right facial swelling that persisted after resolution of an initial febrile illness, with no response to anti-inflammatory therapy. Contrast-enhanced MRI revealed expansive bone destruction of the anterior wall of the right maxillary sinus, cortical discontinuity, and a soft-tissue mass that appeared hypointense on T1WI, hyperintense on T2WI, and exhibited ring-like enhancement. The lesion was surgically resected via a Colles approach with maxillary sinus fenestration. Histopathology confirmed Langerhans cell histiocytosis, and immunohistochemistry was positive for CD1a, S-100, Langerin, and CD68, with a Ki-67 proliferation index of 15%; special stains for acid-fast bacilli, PAS, and silver were negative. Postoperative chemotherapy with vincristine or vindesine was administered. This case underscores the importance of considering Langerhans cell histiocytosis in pediatric patients with refractory facial swelling and destructive bone lesions, and highlights the value of combined surgical and chemotherapeutic management.