History and Evolution of Understanding:

The history of Eosinophilic Granuloma dates back to 1938, when Schaerer diagnosed a lesion on the skull of a child, initially considered to be eosinophilic myeloma or eosinophilic osteomyelitis. It was later described as a new clinical entity by Otani and Ehrlich in 1940, called Solitary Granuloma of Bone. Farber and Green, in 1942, identified its possible relationship with Hand-Schuller-Christian disease and Letter-Siwe disease. In 1944, Jaffe and Lichtenstein introduced the term Eosinophilic Granuloma of Bone, consolidating its association with systemic forms of the disease, now called Langerhans Cell Histiocytosis.

Introduction and Epidemiology:

Eosinophilic Granuloma of Bone, which is the most common form of Langerhans Cell Histiocytosis, represents between 60% and 80% of cases. Despite being a rare benign bone lesion, it occurs mainly in children and adolescents, with a predominance of males. The majority of cases occur in individuals under 21 years of age, with the most affected age group being between five and 15 years. Axial involvement of the skeleton is predominant, with a variety of bones affected, such as the skull, pelvis, ribs and vertebrae, with the spine being responsible for around 10% of cases in children.

Clinical Manifestations and Diagnosis:

The most common symptom of Eosinophilic Granuloma is localized pain, often confused with other causes of headache when it affects the skull. Other forms of Langerhans Cell Histiocytosis can present systemic symptoms, such as fever and diabetes insipidus. The diagnosis is made based on imaging tests, which reveal a bone rarefaction lesion with cortical erosion, in addition to laboratory changes, such as increased ESR and CRP.

Treatment and Prognosis:

The treatment of Eosinophilic Granuloma varies according to the extent of the disease. In isolated cases, an expectant approach or percutaneous biopsy followed by intralesional corticosteroid infusion may be effective. Spontaneous resolution is possible, especially in children, due to the potential for bone remodeling. In more extensive cases or with multiple lesions, systemic treatment with corticosteroids and Vinblastine may be indicated. The prognosis is generally good, with a favorable resolution rate in 97% of cases of solitary lesions.

Conclusion :

Eosinophilic Granuloma of Bone, as the most common form of Langerhans Cell Histiocytosis, represents a diagnostic and therapeutic challenge. However, with a multidisciplinary approach and appropriate therapeutic options, most patients can have a favorable outcome. A thorough understanding of this clinical entity is essential for effective management and an optimistic prognosis.