Association between clinicopathologic characteristics and BRAFV600E expression in Chinese patients with Langerhans cell histiocytosis

Multi-System Langerhans Cell Histiocytosis as a Mimic of IgG4-Related Disease: A Case Report and Literature Review

Langerhans cell histiocytosis (LCH) is a rare disease characterized by the clonal accumulation and/or proliferation of specific dendritic cells resembling normal epidermal Langerhans cells (LCs). Clinical manifestations are variable, depending on the affected tissues or organs, however, LCH with elevated serum IgG4 has not been reported. Herein, we reported a 26-year-old Chinese female multi-system LCH (MS-LCH) who first presented with central diabetes insipidus (CDI), accompanied by panhypopituitarism and hepatic dysfunction. Diagnostic investigations were strongly suspicious of IgG4-RD because of elevated serum IgG4 levels during the process. Furtherly, thyroid and lymph node involvement and biopsy led to the diagnosis of MS-LCH; the strongly positive staining of CD1a, S100, CD207 (langerin), and Ki67 was found. Moreover, after systemic treatment with five cycles of chemotherapy, many lesions were greatly improved. Since both LCH and IgG4-RD are orphan diseases that can affect any organ, the differential diagnosis is challenging, especially when LCH is associated with unexplained serum IgG4 elevation. In this article, the case of a young woman suffering from MS-LCH that affected organs including the pituitary, thyroid, lymph node, and liver was summarized, and relevant literature was reviewed to better equip the diagnosis and treatment in its early stages.

The combination of methotrexate and cytosine arabinoside in newly diagnosed adult Langerhans cell histiocytosis: a prospective phase II interventional clinical trial

BACKGROUND

Langerhans Cell Histiocytosis (LCH) is a rare disease puzzling both children and adults, however outcome of adult patients is unfavorable. This prospective interventional trial aims to test the efficacy and safety of the combination of methotrexate and cytosine arabinoside in adult LCH patients.

METHOD

A total of 36 patients enrolled diagnosed with LCH and treated in our center from 1st Jan, 2014 to 30th Jun, 2016.

RESULT

Nineteen patients underwent the detection of BRAF mutation, with a positive rate of 21.1%. The overall response rate was 100%, only 16.7% achieved complete response. The overall regression rate of osseous lesions was 100%. Regression of central nervous system involvement was also favorable. After a median follow-up of 44 months, the estimated event-free survival was 48.9 months, the overall survival rate was 97.2%. The risk organ involvement showed strong prognostic value, EFS was 34.1 or 54.6 months (p = 0.001) in groups with/without risk organ involvement respectively. Neutropenia and thrombocytopenia were the most common adverse effects.

CONCLUSION

The regimen of methotrexate and cytosine arabinoside (MA) is effective and safe in treating adult LCH patients, and timely preventions may be considered for the high incidence of hematological adverse effects.

TRIAL REGISTRATION

Trial No. NCT02389400 on Clinicaltrials.gov, registered on 10th Mar. 2015.

Pediatric Langerhans Cell Histiocytosis with BRAF Mutation Affecting Sacral Vertebra: A Case Report and Disease Review

BACKGROUND

Histiocytoses are rare diseases affecting mainly children and can occur in any organ of the body. They are divided into Langerhans type and non-Langerhans type. Langerhans cell histiocytosis (LCH) mainly affects skin, bones, and lymph nodes but can also affect the hematopoietic system. Bone lesions can be critical when they involve skull base, orbit, or vertebrae and can cause permanent neurological sequelae or death. Histopathological diagnosis and molecular markers are the mainstay for accurate diagnosis. Sixty percent of LCH cases show mutation in the BRAF oncogene. They are treated with multimodality treatment which includes surgery, chemotherapy, and BRAF inhibitor therapy. Owing to the rarity of the disease and paucity of cases, the understanding and standardization of treatment is still evolving.

CASE REPORT

A 14-year-old boy presented with backache, and his imaging showed erosion of first sacral vertebral body with soft tissue component impinging and compressing the spinal canal. Histopathology and molecular diagnosis showed LCH which was positive for BRAF gene mutation. Adequate canal decompression and near-total removal of the disease load with fixation of weight-bearing axis resulted in symptomatic relief and good outcome. Systemic chemotherapy was given for the small residual disease due to fear of recurrence and impending neurological complications. He responded well to first-line therapy with vinblastine and prednisolone with complete resolution of disease on a follow-up scan.

CONCLUSION

Accurate diagnosis with molecular markers is essential for a good outcome of LCH. Treatment of lesions at critical locations like skull base, orbit, or vertebral axis needs to be tailored to prevent permanent neurological deficits. Newer therapies in the form of BRAF inhibitors are on the way, but the efficacy and benefit need to be tested.