A 22‐Year Old Woman with Right Eyelid Swelling

Clinical History and Imaging

A 22‐year old female presented with a five‐week history of right retroorbital pain and eyelid swelling. She denied headaches, loss of vision, focal neurological symptoms or ocular symptoms. On exam she had tenderness over right eyebrow and temporal bone. Her past medical history was unremarkable. An ophthalmologist initially saw her and a CT‐scan was ordered. The scan showed an orbital bony lesion, which contained a solid component as well as a fluid level without calcifications or a bony matrix (Figure 1a). A subsequent MRI revealed a contrast‐enhancing lesion eroding the roof of the orbit posterolaterally on the right (Figure 1b). Involvement of the inner table of the temporal bone was also demonstrated on MRI. The patient was referred to our center at this time for further evaluation. A CT angiogram was performed to assess the vascularity of the lesion and whether or not any preoperative embolization would be of utility. On the angiogram no vascular abnormalities could be identified intracranially. One month after her initial presentation she successfully underwent a bifrontal craniotomy with resection of the orbito‐temporal lesion and placement of a prosthetic right orbital roof.

Figure 1.

Gross and Microscopic Pathology

Gross examination revealed non‐descript brown‐tan and hemorrhagic soft tissues adherent to fragments of partially eroded bone. A separate specimen submitted as “dural margin” was composed of brown, hemorrhagic, lobulated, and somewhat cystic soft tissue adherent to the outer surface of normal dura. Hematoxylin and eosin stained sections of the specimens showed nodular aggregates of large mononuclear cells (Figure 1c) with high nuclear‐to‐cytoplasmic ratios characterized by indented and clefted nuclei (Figure 1d). These cells contained amphophilic cytoplasm, had distinct cytoplasmic borders, and showed positivity for both S‐100 and CD1a by immunohistochemistry (Figures 1e and 1f, respectively). These nodules of atypical cells were accompanied by an exuberant mixed inflammatory infiltrate composed of many lymphocytes, plasma cells, and eosinophils (Figure 1g). Occasional multinucleate giant cells were seen throughout the inflammatory infiltrate (Figure 1h). Scattered CD68‐positive histiocytes (Figure 1i) that were negative for both S‐100 and CD1a were seen adjacent to atypical cells within the lesional nodules and within the mixed inflammatory infiltrate. What is your diagnosis?

Diagnosis

Langerhans cell histiocytosis, WHO Grade I.

Discussion

Before resection took place, the differential diagnosis favored a giant cell tumor or an aneurysmal bone cyst above Langerhans cell histiocytosis (LCH). Langerhans cell histiocytosis is mostly considered a pediatric disease and occurrence in adults is rare with a reported incidence of approximately 1‐2 in a million. This disease was previously known as Histiocytosis X. In 1953 Liechtenstein grouped the clinical syndromes eosinophillic granuloma, Hand‐Schüller‐Christian disease, and Abt‐Letterer‐Siwe disease all under this term when he found their histological features to be equal 1. The Langerhans cell, with its characteristic bean‐shaped nucleus often with a central groove, was later found to be of great pathogenetic importance and the name of the disease was changed from Histiocytosis X to Langerhans cell histiocytosis 3. LCH is now known to be caused by a monoclonal proliferation of Langerhans cells, which are S‐100 and CD1a positive and CD68‐negative with immunohistochemistry. 1

Nowadays, the disease is grouped in unifocal, multifocal and disseminated disease. Less than 20 cases of LCH localized in the orbit have been described over the years. Case reports illustrate that orbital LCH in adults mostly presents as an unifocal disease 3, 4. Nonetheless, workup should always include a complete blood count, CT‐scans and MRI scans to rule out other sites of involvement. Different treatment modalities are used to treat unifocal orbital disease. The prognosis of unifocal disease is excellent after surgical resection 1, 2, 3, 4.

The patient we described made a good recovery after surgery. A MRI‐scan one‐month after the surgery revealed a complete resection of the lesion. All of her initial symptoms disappeared after the surgery with no new complaints. She received the full workup for LCH to look for other organ and bony lesions with a complete X‐ray bone survey and PET/CT‐scans of the abdomen, chest, head and neck. Laboratory tests including a complete blood count, comprehensive metabolic panel, erythrocyte sedimentary rate, urinary analysis, thyroid tests, vitamin B12, LH, FSH, prolactin, IGF‐1, cortisol and ACTH were performed. All tests were within the normal range and no other sites of disease elsewhere in the body could be identified on imaging. Like most described cases of orbital LCH, our case could be classified as unifocal disease. At this time the patient will not receive any further treatment. We will continue to closely monitor the patient in the future for a possible recurrence of LCH.