Introduction: Langerhans cell histiocytosis (LCH) is a quite rare clonal disorder of the monocyta-macrophag system characterized by the abnormal, uncontrolled proliferation of pathological Langerhans cells resulting in focal or systemic effects. It’s clinical presentation is highly variable and complex, dependig on the organs involved. The most frequent manifestation of the adult LCH is the skeletal system.
Case report: Here, we present a rare case of a 56 years old woman with localized bone pain and swelling in her right distal femur. First, her clinical presentation and results (laboratory tests, two-directional X-rays, ultrasound examination, MRI) were diagnosed as chronic osteomyelitis. However, later the same manifestation of the left femur was also discovered. The bilateral, unusual location of the skeletal lesions raised the question of a systemic disease. During surgical treatment, bone biopsies were taken, which revealed an oncogen BRAF W600E immunopositive LCH disease by using cytological examination and immuno-histochemical staining. The microbiologic examinations were negative.
Conclusions: Based on the few LCH literature available, the aim of this article was to present the specific features of X-Ray and MR image of both femurs of the patient, which may refer to LCH: 1) in both long tubular bones diaphysis and metaphysis were involved; 2) the image of the trabecular and cortical bone destruction, ovoid or round, radiolucent areas in the medullary bone with multiple osteolytic or cystic lesions with irregular, sclerotic margins; 3) aggressive periosteal reaction with characteristic single-layer or multi-layer lamellar onion-skin (endosteal scalloping) morphology; 4) surrounding soft tissue infiltration, oedema; 5) non specific, extensive signal intensity changes within the bone marrow on MRI.
The routine application of X-ray and MRI on long tubular bones could help with the rare diagnosis of adult LCH.