Radiologic findings that aid in the reduction of misdiagnoses of Langerhans cell histiocytosis of the bone: a retrospective study

Abstract

Background: This study aimed to identify the characteristic radiological signs for the diagnosis of Langerhans cell histiocytosis (LCH) of the bone.

Methods: We retrospectively studied 82 cases of LCH with bone lesions confirmed by pathology. Clinical and radiological features of the patients were analyzed.

Results: A total of 64 and 18 patients had single and multiple bone lesions, respectively. With regard to LCH with single bone lesions, 37.5% (24/64) of lesions were located in the skull and presented as bone destruction with or without soft tissue mass. The correct diagnosis rate of these lesions was 60.0% (9/15) in children and adolescents, but was only 22.2% (2/9) in adults. A total of 26.5% (17/64) of the solitary lesions were found in the spine. Of these, 88.2% (15/17) were located in the vertebral body and appeared to have different degrees of collapse, and 66.7% (10/15) of these lesions were correctly diagnosed. Of the unifocal lesions, 21.8% (14/64) were located in other flat and irregular bones and manifested as osteolysis. Only 21.4% (3/14) of these cases were correctly diagnosed. In total, 14.1% (9/64) of the isolated bone LCH lesions were located in the long bones. Of these, 77.8% (7/9) were located in the diaphysis and presented as central bone destruction with or without fusiform periosteal reaction and extensive peripheral edema, of which 42.9% (3/7) were correctly diagnosed before surgery or biopsy. With regard to LCH with multiple bony destructive lesions, 71.4% (10/14) of cases in children and adolescents were correctly diagnosed; however, all four cases among adults were misdiagnosed.

Conclusion: In all age groups, isolated diaphyseal destruction of the long bone with fusiform periosteal reaction and extensive peripheral edema, vertebra plana of the spine, and bevelled edge of skull defects accompanied by soft tissue masses strongly suggest LCH diagnosis. Moreover, the multiple bone osteolytic destruction in children and adolescents strongly suggests LCH diagnosis. Familiarity with these typical radiological signs of LCH is necessary to decrease misdiagnoses.

Keywords: Bone lesion; Diagnostic imaging; Differential; Langerhans cell histiocytosis; Radiology.

Fig. 1

Axial computed tomography of a 2-year-old male patient (a, b) showing bevelled-edge appearance in the left frontal bone. Axial MR images show hyperintensity on T2WI (c), hypointensity on T1WI (d), and slight hypointensity on diffusion weighted imaging (e). The diagnosis of LCH was confirmed by pathology after surgery (pathological slice HE × 200) (f)

Fig. 2

Spinal X-ray and sagittal MR image of the cervical spine of a 19-year-old male patient with neck pain and restricted neck motion. X-ray (a) shows a lesion in the C6 associated with severe vertebral collapse. The lesion shows slight hypointensity on T1WI (b), hyperintensity on T2WI (c), and hyperintensity on fat-saturated T2WI (d, e), associated with obvious marrow and soft tissue edema, and prevertebral and epidural soft tissue extension. The diagnosis of LCH was confirmed by pathology after surgery (pathological slice HE × 200) (f)

Fig. 3

X-ray (a), CT (b), and MRI (c-e) of the left femur of a 12-year-old female patient. X-ray image (a) and CT (b) show an oval lesion in the middle left femoral diaphysis, associated with fusiform periosteal reaction. The lesion shows hyperintense signals and surrounding marrow and soft tissue oedema on FS-T2WI (c), hypointense signal on T1WI (d), and obvious enhancement after gadolinium administration. The diagnosis of LCH was confirmed by pathology after surgery (pathological slice HE × 400) (f)