Langerhans cell histiocytosis (LCH) is a rare clonal proliferative disorder of bone marrow–derived dendritic cells that occurs infrequently in adults. Clinical manifestations vary by organ involvement, and central nervous system (CNS) disease presents important therapeutic and prognostic challenges because neurological damage can be irreversible. The source reports two adult-onset LCH cases with contrasting presentations and outcomes to illustrate how lesion distribution influences management and recovery.
A 36-year-old woman presented with a persistent headache. Neuroimaging identified a solitary osteolytic lesion in the left parietal bone with associated dural thickening. The lesion was surgically resected. Histopathological analysis revealed characteristic Langerhans cells and immunostaining was positive for S-100, confirming the diagnosis of LCH confined to the calvarium. Following surgery, the patient was treated with bisphosphonates. According to the report, she remained clinically stable without evidence of systemic involvement.
A 26-year-old man presented with neurobehavioral and endocrine symptoms including cognitive impairment, somnolence, polyuria, and endocrine dysfunction. Magnetic resonance imaging showed an enhancing lesion in the hypothalamic region. Histopathology and immunohistochemistry confirmed LCH with positivity for CD1a and S-100. Molecular testing using pyrosequencing did not detect the BRAF V600E mutation. The patient received systemic chemotherapy with cladribine, which achieved partial radiographic tumor regression. Despite cytoreduction, the patient’s cognitive dysfunction persisted.
Both cases were established by tissue diagnosis with characteristic morphology and supportive immunohistochemical markers. In the calvarial case, S-100 positivity was reported; in the hypothalamic case, both CD1a and S-100 were positive. The hypothalamic lesion underwent molecular analysis by pyrosequencing for BRAF V600E, which was reported as not detected. The source emphasizes the role of imaging to localize lesions and biopsy with immunohistochemistry to confirm LCH.
Management differed according to lesion location and extent. The calvarial lesion was treated surgically followed by bisphosphonate therapy, and the patient remained stable without systemic disease. The hypothalamic lesion required systemic therapy; cladribine was administered and achieved partial tumor regression radiographically. However, in that case neurological sequelae — notably persistent cognitive dysfunction — did not resolve despite treatment. The report thus contrasts a localized, surgically managed calvarial lesion with a CNS-involved lesion that required systemic cytoreduction.
These two adult cases illustrate that disease distribution, particularly CNS involvement, informs therapeutic decisions and strongly influences neurological outcomes. When LCH is limited to accessible bone lesions, surgical resection combined with adjuvant measures such as bisphosphonates may achieve stability without systemic spread. By contrast, hypothalamic or other CNS lesions often necessitate systemic chemotherapy; even when cytoreductive therapy produces partial tumor regression, neurological function may not recover fully. The absence of BRAF V600E in the reported hypothalamic case is noted, though the report does not provide further molecular or long-term comparative data.
The authors underline the importance of early diagnosis and proactive systemic evaluation because functional recovery can be limited once neurological damage has occurred, even after apparently effective cytoreductive treatment. Early recognition of CNS involvement may therefore affect both timing and choice of therapies aimed at preserving neurological function.
The two adult-onset LCH cases highlight contrasting clinical courses determined primarily by lesion site. A solitary calvarial lesion treated surgically with bisphosphonate therapy remained stable without systemic disease, while a hypothalamic LCH required systemic cladribine chemotherapy with partial regression but persistent cognitive impairment. These cases reinforce that CNS involvement presents a critical therapeutic challenge and that early diagnosis and systemic assessment are essential because neurological recovery can be incomplete despite tumor control.
Note: The preceding summary and discussion reflect the data and conclusions reported in the source. Details such as specific dosing, duration of treatments, long-term follow-up intervals, and additional laboratory or imaging metrics were not reported in the source abstract.