Langerhans Cell Histiocytosis: Temporal Bone Invasion in an Adult

A 52-year-old woman with a medical history of hypertension, hyperthyroidism, diabetes insipidus, and Horner syndrome was referred to our clinic for evaluation of a skull base mass. She initially presented to an outside facility with ear pain, vertigo, and neck pain. She was referred to a spine specialist and subsequently underwent two spinal procedures for presumed cervical pseudoarthrosis. Despite treatment, her symptoms persisted and she developed bloody otorrhea and hearing loss in the left ear. Radiographic imaging demonstrated a destructive lesion of the left mastoid and skull base, and she was referred to our institution for further management.

Physical examination showed a mass filling the patient's left external auditory canal. A biopsy in clinic was deferred as there was concern that this mass might be a vascular tumor, making hemostasis difficult to achieve in the office setting. Magnetic resonance imaging (MRI) demonstrated a large, enhancing mass in the left mastoid that extended into the external auditory canal (figure 1). There were aggressive features noted, such as bony erosion and possible dural involvement, but the ossicles were spared.

Figure 1.

Axial (A) and Coronal (B) MRIs of the Patient's Head Show a Destructive Lesion in the Left Mastoid.

At surgery, massive bone destruction was found along the base of the skull and the inferior part of the mastoid that extended into the superior aspect of the musculature of the neck. The destructive lesion was adherent to the dura but did not transgress it. The tumor was debulked and grossly dissected away from the dura. No cerebrospinal fluid leak was encountered during the dissection, and the facial nerve was found to be intact. The surgical defect was obliterated using an occipital myosubcutaneous flap.

Microscopic examination of the biopsy revealed clusters and sheets of Langerhans cells (figure 2). The tumor cells had grooved and irregularly contorted nuclei with inconspicuous nucleoli. Admixed eosinophils were also noted. The tumor cells showed immunoreactivity for S-100 protein and CD 1a, confirming a diagnosis of Langerhans cell histiocytosis (LCH).

Figure 2.

Pathology demonstrates diffuse proliferation of Langerhans cells with nuclear folds or grooves. Hematoxylin and eosin stain shows admixed eosinophils present in the background (A; hematoxylin and eosin, original magnification x60). Immunohistochemistry reveals that the Langerhans cells are positive for S-100 protein (B) and CD1a (C).

Radiographic imaging—including computed tomography (CT) of the chest, abdomen, and pelvis and an osseous survey—were ordered for further evaluation and to determine the extent of the disease. The imaging demonstrated disseminated disease with a destructive lesion of the right ilium and abnormal soft tissue in the bilateral perinephric space. The oncologists recommended systemic chemotherapy because further surgical debulking was no longer practical. The patient expired several months later from complications of her disease and her comorbid conditions, as well as poor compliance.

LCH is caused by the proliferation and accumulation of a specific histiocyte, the Langerhans cell. The disease can involve any bone, but most lesions occur in the flat bones of the skull, pelvis, spine, mandible, and ribs. ¹ Imaging of the skull will often reveal lytic lesions with scalloped edges. CT is better suited for demonstrating bone detail and MRI for bone marrow and soft-tissue involvement.

Patients with limited initial involvement of the temporal bone have a better prognosis on long-term follow-up than do patients with the multisystemic form of LCH. ² Temporal bone involvement is bilateral in 31% of cases, and otologic symptoms were the initial presentation in 25% of these cases. ³

Despite the characteristic of extensive destruction of the temporal bone in this disease, the facial nerve is surprisingly resistant to destruction, and facial nerve palsy is rare. If present, facial nerve palsies are likely caused by compromise of blood supply to the nerve. ³

Histopathologically, LCH is characterized by proliferation of atypical Langerhans cells that form granulomas. Langerhans cells have cytoplasmic inclusion bodies known as Birbeck granules; a definitive diagnosis requires electron microscopy of Birbeck granules or CD1 antigenic determinants by immunohistochemistry. ³

Treatment of temporal bone lesions remains controversial. Surgery is required to make the histologic diagnosis but does not improve outcome. Treatment options include intralesional steroids, systemic steroids, systemic chemotherapy, and surgical curettage. Other authors have reported good local disease control with low-dose radiotherapy. ⁴

LCH is rare in adults compared to the pediatric population. The age at presentation does not appear to predict the severity or course of the disease in adults, in contrast to children. Multisystemic disease is the only known prognostic factor. Although rare in adults, LCH is an important disease process that needs to be considered in the differential in patients presenting with refractory otologic symptoms.

This case report was reviewed and approved by the Institutional Review Board of Wake Forest University Baptist Medical Center.