Langerhans Cell Histiocytosis, WHO Grade I
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.
Contributed by Vincent A. van Vugt, Aditya Kesari, Karra A. Muller, MD, PhD, Bob Carter, MD, PhD, Scott R. Vandenberg, MD, PhD, Santosh Kesari, MD, PhD