A 22-year-old male patient presented with recurrent headaches and soft tissue swelling in the right forehead for three months. The patient started to notice the soft tissue swelling only after the recent headaches. The neurological examination was normal. There is no history of trauma to the head and the headaches were not associated with vomiting.
Multidetector Computed Tomography [MDCT] of the skull; lateral projection scout image showed a well defined oval-shaped lytic lesion involving the right frontal bone (Fig. 1). Non-contrast MDCT head in soft tissue window (Fig. 2) and bone window (Fig. 3) x in axial plane showed a well-defined osteolytic lesion in the right frontal bone involving both the inner and outer tables of the skull with bevelled edges and without sclerotic margin. The lesion showed epidural and subcutaneous soft tissue components.
Based on imaging, the diagnosis of Langerhans Cell Histiocytosis of the skull was suspected which was confirmed by histopathology.
Langerhans Cell Histiocytosis [LCH], is a proliferative disorder of Langerhans cells. It is a rare disease characterized by the accumulation of macrophage, dendritic cell, or monocyte-derived cells in various tissues and organs of children and adults with a male to female preponderance ratio of 3:1 [1]. A Few authors implicated an autoimmune complex in pathogenesis and some recent studies, based on molecular analysis, have demonstrated that the Langerhans-cell population within LCH lesions is clonal in origin. These data strongly suggest that somatic genetic changes can contribute to the aetiology and pathogenesis of LCH, as documented in neoplastic disorders[2].
Clinical presentations of LCH vary widely, from an asymptomatic solitary bone lesion to multisystem life-threatening afflictions[3]. In bones, this may cause pain and adjacent soft tissue swelling and might cause headaches, as in our patient's case, but most lesions are usually asymptomatic.
LCH can involve any bone, but there is a predilection for the axial skeleton, with more than 50% of bone lesions[4] occurring in the flat bones (skull, ribs, pelvis). Microscopically they show characteristic Birbeck granules and immunohistochemistry reveals the expression of CD1a, CD207, and HLA-DR antigens.
Plain radiography is the initial modality of choice. The usual appearance is a well-defined round/ oval, central destructive, lytic lesion involving the diploic space with both inner and outer table involvement. The edges of the lesion are often bevelled.
On CT, LCH appears as a solitary or multiple punched out radiolucent defect without reactive sclerosis and is often associated with epidural soft tissue components [3].
On MRI T1 weighted imaging, a mildly high signal intensity lesion is noted. On T2 weighted imaging, a stippled central low signal with peripheral high signal intensity is seen. Areas of irregular central non-enhancement with peripheral enhancement represents central necrosis.
Treatment includes curettage, intralesional steroid injection, or radiation therapy. Mortality and morbidity are associated with the clinical presentation and age of onset of the disease. The worst prognosis is noted in neonates presenting with the disseminated form. This differentiation is important because the prognosis is more favourable with the focal disease rather than multifocal disseminated disease, which involves organs other than the skeletal system
Take home message: Skull is the most common location for LCH. Familiarity with typical imaging appearances of lytic skull lesions is necessary for appropriate patient management.
Written informed patient consent for publication has been obtained.
Langerhans cell histiocytosis
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Based on the provided cranial CT and X-ray images, the following observations can be made:
1. A clearly defined lytic lesion is seen in the right frontal bone, with sharp margins, displaying a “punched-out” or “drilled” appearance.
2. Both the inner and outer tables in the lesion area are involved, showing “depressed” or “erosive” changes. In some regions, an “inverted cup” or “overlapping edge” sign can be observed.
3. On the soft tissue window, mild swelling or a soft tissue mass is noted in the subcutaneous region of the right forehead, corresponding to the cortical bone destruction of the skull.
4. No obvious intracranial parenchymal compression is seen; intracranial soft tissue appears relatively stable.
Overall imaging findings are consistent with a focal lytic lesion commonly found in the skull.
Combining the patient’s age, clinical symptoms (headache and a right frontal lump), and the lytic changes on imaging, the following diagnoses or differential diagnoses are considered:
Comprehensive analysis shows the patient is young, presenting with a frontal lump and headache, and imaging reveals a localized, irregular lytic defect in the frontal skull without systemic involvement. Considering the typical age of onset and imaging features of LCH, Langerhans Cell Histiocytosis (LCH) best fits this presentation.
If uncertainty remains, further diagnostic confirmation by bone biopsy or immunohistochemical markers (e.g., CD1a, CD207) can be considered.
1. Treatment Strategy:
2. Rehabilitation and Exercise Prescription:
Given that the patient’s primary symptoms are localized pain (headache) and soft tissue swelling, and overall physical condition may still be relatively good, an individualized, gradual rehabilitation program is advisable. The FITT-VP principle is suggested:
Precautions:
Disclaimer: This report is for reference only and does not replace an in-person consultation or professional medical opinion. If you have any questions or changes in your condition, please visit a qualified medical institution promptly.
Langerhans cell histiocytosis
