Partial IFN-γR1 deficiency complicated by disseminated BCG infection mimicking Langerhans cell histiocytosis

Abstract

A 9-month-old boy presented with persistent and recurring fever, left axillary lymphadenopathy, and systemic pustular eruption. His clinical features including an osteolytic lesion in the skull (forehead), skin lesions, lymphadenopathy, and elevated levels of soluble interleukin-2 receptor in the serum mimicked those found in patients with multiorgan Langerhans cell histiocytosis. BCG was identified in a lymph node biopsy specimen, which confirmed the diagnosis of BCG-itis. His symptoms quickly improved with the antituberculosis drugs isoniazid and rifampicin. Mendelian susceptibility to mycobacterial disease (MSMD) was suspected as an underlying pathology. On the basis of mutation search findings, he was diagnosed as having partial IFN-γR1 deficiency with a previously known de novo heterozygous mutation in IFNGR1. We should pay attention to the resemblance in the clinical features of Langerhans cell histiocytosis and BCG-itis.