Aggressive Langerhans Cell Histiocytosis (LCH) of Right Temporal Bone

Summary

Langerhans cell histiocytosis (LCH) is a relatively rare disease. This article explores the clinical and pathological features of Langerhans cell histiocytosis, its differential diagnosis, and biological characteristics.

Abstract

Langerhans cell histiocytosis is a relatively rare disease. This article explores the clinicopathological features, differential diagnosis, and biological characteristics of Langerhans cell histiocytosis. A comprehensive analysis was conducted on the clinical data, clinical characteristics, histological observations, immunohistochemical studies, pathological features, treatment, and prognosis of one case of Langerhans cell histiocytosis occurring in the temporal bone, to enhance clinical understanding of this disease. The patient is a 14-year-old boy, initially presenting with a mass in the right temporal region. Upon admission, a complete examination was performed. Both preoperative CT and MRI indicated damage to the right temporal bone. Following complete resection of the lesion during surgery, histological examination revealed extensive infiltration of Langerhans cells accompanied by eosinophilia. Immunohistochemical staining showed positive CD1a and S-100, confirming the diagnosis of Langerhans cell histiocytosis. No signs of recurrence were observed during the 24-month postoperative follow-up, and the prognosis was favorable. Langerhans cell histiocytosis is a rare disease affecting the reticuloendothelial system, mainly characterized by abnormal proliferation of Langerhans cells. Although the histological morphology appears benign, the biological behavior is highly invasive and destructive, often involving multiple organ systems such as bones (e.g., temporal bone), lungs, skin, and lymph nodes. The condition has a high incidence in childhood and requires early diagnosis and intervention.

Introduction

Langerhans Cell Histiocytosis (LCH) is a rare disease characterized by abnormal proliferation of Langerhans cells, a type of histiocytosis^1,2. The disease can involve bone, skin, lymph nodes, and internal organs, with the skull being the most common site of single bone lesions, accounting for approximately 60%-80% of pediatric LCH cases^1,3. The pathogenesis is not fully understood and may be associated with somatic gene mutations (such as BRAF V600E), immune microenvironment abnormalities, or activation of inflammatory factors³. Clinical manifestations vary depending on the affected site. Cranial lesions typically present as a localized painless or mildly painful mass, often accompanied by bone destruction, scalp swelling, and tenderness. In severe cases, epidural invasion or intracranial involvement may lead to neurological symptoms.

Diagnosis requires a combination of imaging, pathology, and immunohistochemistry^2,3. X-ray or CT of the skull often reveals osteolytic damage with well-defined margins, described as "perforated" or "geoglyphic" defects. MRI can further assess the extent of soft tissue involvement. Biopsy confirms the diagnosis, typically showing a large number of eosinophilic infiltrates and foam-like histiocytes. Immunohistochemical markers such as CD1a, CD207 (Langerin), and S-100 protein provide key diagnostic evidence. Differential diagnosis should exclude bone tumors such as Ewing's sarcoma, osteomyelitis, and metastatic lesions.

Treatment strategies should be developed based on the extent of the lesion and systemic involvement^2,4. For localized cranial LCH, surgical resection is the preferred option, particularly in cases with a single lesion, an accessible location, and no significant neurovascular invasion. Complete resection of the lesion should be achieved while ensuring safety. During surgery, care must be taken to protect the dural membrane and surrounding normal bone tissue to avoid postoperative cerebrospinal fluid leakage or infection. Titanium mesh or bone cement can be used to repair larger defects after resection. If the lesion is located deep within or adjacent to critical structures (e.g., sagittal sinus, optic nerve), postoperative low-dose radiotherapy (5-15 Gy) or oral hormone therapy may be considered. Cases with multisystem involvement or postoperative residual disease may be treated with chemotherapy (e.g., vinblastine combined with prednisone), and targeted agents (e.g., BRAF inhibitors) have shown high efficacy in mutation-positive cases.

Prognosis is closely related to age at onset, affected organs, and response to treatment^1,3,5. The 5-year survival rate for localized cranial LCH after standard treatment exceeds 95%, although approximately 10%-20% of cases may relapse. Regular imaging follow-up (every 3-6 months) enables early detection of new lesions. Involvement of multiple systems (e.g., liver, lung, bone marrow) or "high-risk organs: is associated with poorer prognosis and necessitates long-term monitoring of endocrine function (e.g., diabetes insipidus). In recent years, multidisciplinary collaboration and individualized treatment have significantly improved patient quality of life, though long-term sequelae (such as bone deformities and neurocognitive disorders) still require attention.

CASE PRESENTATION:

A 14-year-old male was admitted to the hospital with right temporal lesions present for seven months. Initially, the mass was approximately the size of a bean (less than 1 cm) (Figure 1A), followed by progressive growth, reaching a 3 cm elevation five months later (Figure 1B). The mass had limited mobility, an ill-defined boundary, no subjective symptoms, no swelling, surface rupture, or induration, and no radiating pain. Neurological examination revealed no positive signs. The first CT scan (on January 29, 2019) showed a 1 cm mass involving the right temporal bone (Figure 1A). A second CT scan (on May 3, 2019) revealed a 3 cm mass in the same region (Figure 1B; Figure 2A). MRI demonstrated a 2.7 cm hyperintense mass on T1-enhanced images.

Diagnosis, assessment, and plan

After evaluation and discussion, it was concluded that the cranial lesion required surgical treatment. After communicating with the patient and family members, preoperative preparation was carried out. The pathological properties were determined by excision of the lesion. According to the pathological results, the next treatment plan was determined.

After evaluation and discussion, it was concluded that the cranial lesion required surgical treatment. Following communication with the patient and family members, preoperative preparations were initiated. The pathological nature of the lesion was determined through surgical excision. Based on the pathological findings, the subsequent treatment plan was established.

Protocol

The study was approved by the Ethics Committee of Affiliated Hospital 2 of Nantong University. The patient provided written consent to participate in the study. The reagents and equipment used are listed in the Table of Materials.

1. Preoperative preparation

1. Liver and kidney function, coagulation index, and other relevant indicators were evaluated to exclude surgical contraindications.
2. Magnetic resonance navigation examination was performed, and the data were entered into the navigation system.

2. Surgical preparation

1. The patient was placed in a supine position on the operating table. After anesthetizing the patient following institutionally approved protocols, the head was secured using a three-pin head frame and tilted to the left.
2. The vital signs were continuously monitored throughout the procedure.
3. Navigation, registration, surgical route planning, and surgical incision design were completed prior to the operation.

3. Surgical procedure

1. The surgical area was prepared in a sterile manner, with care taken to prevent disinfectant and other substances from entering the patient's eyes.
2. The scalp was incised according to the pre-designed skin incision. Specifically, a right temporal horseshoe-shaped incision measuring 4 cm × 6 cm was made, and the temporal flap was elevated.
3. Under navigation guidance, the skull was drilled, and a bone flap was created using a milling cutter along the edge of the tumor invasion. The bone flap was detached and freed. A partial dural defect was observed, and the bone flap measured approximately 2.5 cm².
4. Artificial meninges were used to repair the dural defect.
5. The skull defect was not further repaired.
6. Hemostasis was achieved at the wound site.
7. The scalp was sutured, and the incision was closed using 2-0 or 3-0 single sutures.
8. The head incision was wrapped, and the head frame was removed.
9. Anesthesia was discontinued, and recovery preparation was completed. The specimen was sent for pathological examination.
10. Extubation was performed, and the patient was transferred from the operating room back to the ward.

4. Follow-up procedures

1. Postoperative vital signs, including neurological status, were closely monitored to detect any early signs of intracranial complications.
2. Prophylactic antibiotics and analgesics were administered in accordance with standard clinical protocols.
3. A postoperative CT scan and MRI were performed to assess the extent of lesion removal and to rule out complications such as hemorrhage or edema.
4. Wound healing and signs of infection were evaluated during daily clinical rounds.
5. The patient was discharged after achieving a stable postoperative condition.
6. Follow-up imaging and clinical evaluations were scheduled at 1 month, 3 month, and 6 months postoperatively to monitor for recurrence or long-term complications.
7. Endocrine function and neurocognitive status were also assessed periodically due to the risk of long-term sequelae associated with Langerhans cell histiocytosis.

Results

The intraoperative neoplasm capsule was incomplete, with a soft texture, poor blood supply, and invasive growth. Adhesion to surrounding tissue was noted, with the deep surface adjacent to the dura mater. Destruction of the right temporal bone was observed, with a lesion size of approximately 3 cm (Figure 3A-D). The mass was completely removed (Figure 1C; Figure 2B; ...

Discussion

Langerhans Cell Histiocytosis (LCH): Incidence and clinical features

Langerhans cell histiocytosis (LCH) primarily affects children, with peak incidence occurring between 1-3 years of age. The male-to-female ratio ranges from 1.2:1 to 2:1. The incidence in adults is low. LCH is a rare disease and presents with diverse clinical manifestations.

Origin of LCH

LCH was first named by Lichtenstein in 1953, base...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
artificial dura	Beijing Tianyifu Biomaterials Co., LTD	www.pwmedtech.com
microscope	Carl Zeiss AG	Pandora 900
neuronavigator	Shanghai Fudan Navigation Company	www.fudanns.com