Cutaneous manifestation is a common presentation of LCH and is usually a leading clue for the disease diagnosis. Having cutaneous lesions did not show a significantly early age onset at diagnosis compared to those without skin lesions, P value = 0.71. In the present study, cutaneous findings were found as 77.7%. Seborrheic dermatitis-like lesions were the most common cutaneous type (42.8%), followed by papules/nodules/masses (28.5%), petechiae/hemorrhagic lesions (17.8%), and eczematous lesions (10.7%). Time to diagnosis of LCH presented with seborrheic dermatitis-like lesions was significantly longer than other cutaneous presentations, P value = 0.0011.Conclusion: Patients with LCH who had the manifestations of seborrheic dermatitis-like lesions can have diagnosis delayed due to the difficulty in distinguishing these lesions from normal seborrheic dermatitis lesions. Petechiae/hemorrhagic cutaneous signs in addition to the normal seborrheic dermatitis is the clue for early detection of the disease. To improve early detection of LCH, general pediatricians should be alerted to be aware of these skin symptoms, and if they persist, a dermatologist, pediatric if available, should be immediately consulted. What is Known? • Cutaneous manifestation is a common presentation of LCH and is usually a leading clue for the disease diagnosis. What is New? • Patients with LCH who have the manifestations of seborrheic dermatitis-like lesions can have a delayed diagnosis due to the difficulty in distinguishing normal from seborrheic dermatitis lesions. • Petechiae/hemorrhagic cutaneous signs in addition to the normal seborrheic dermatitis are the clue to the early disease detection.

Thymic involvement by Langerhans cell histiocytosis (LCH) has been described mainly in isolated case reports. A description of the histopathologic patterns of LCH proliferations in the thymus, together with therapeutic implications, has not, to our knowledge, been previously addressed. The pathology consultation files at Children\'s Hospital of Pittsburgh of the University of Pennsylvania Medical Center were reviewed for cases of thymic involvement by LCH. Relevant cases in the literature were also reviewed, and the histopathology and clinical course of those cases were collected. Nine consultation cases of thymic involvement were reviewed, together with 23 cases in the literature, which provided adequate pathologic description and ancillary confirmation (n  =  32), revealing 4 distinct pathologic groups. Group 1 showed microscopic collection of hyperplastic LCH-like cells in incidental thymectomies of patients without LCH disease, requiring no further treatment (n  =  7; 22%). Group 2 showed solitary and/or cystic LCH of the thymus with gland disruption, and at least 3 cases resolved without systemic therapy (n  =  10; 31%). Group 3 showed more variable thymic involvement in multisystemic LCH disease, with either a medullary restricted pattern or more diffuse gland involvement, requiring adjuvant therapy and having a higher mortality rate (n  =  13; 41%). Group 4 showed a mixed histiocytic lesion with a concurrent LCH and juvenile xanthogranuloma-like proliferation (n  =  2; 6%). Thymic involvement in LCH is quite rare. Based on our cases and those in the literature, we propose 4 distinct pathologic groups of thymic involvement in Langerhans cell proliferations with relevance for diagnosis and treatment.

OBJECTIVE: To evaluate the long-term tolerance of bisphosphonates proposed as an alternative therapeutic option for symptomatic unresectable benign bone tumors and to evaluate the long-term efficacy of this treatment.
METHODS: From March 2007 to March 2011, patients with unresectable symptomatic benign bone tumors were consecutively included in this institutional review board-approved study and treated with bisphosphonates. Prospectively long-term follow-up is reported. The study endpoints were to describe the long-term tolerance, the clinical evolution of pain for each patient and the radiological success defined as a complete disappearance of inflammation and ossification of the bone lesion. All complications and side effects were recorded.
RESULTS: Eight patients (mean age 16 years; range 7-42) with various tumor subtypes were included: aneurysmal bone cysts (N=5), Langerhans cell histiocytosis (N=1), osteoblastoma (N=1), and a giant cell tumor (N=1). Tumors were located in cervical (N=4) or thoracic (N=1) vertebrae, femoral shaft (N=1), acetabulum (N=1) and sacrum (N=1). Mean number of bisphosphonate cycles was 3 (range: 1-6) over a median period of 10 months. The median clinical and imaging follow-up period was 21 months (6 to 63 months). No severe complications due to treatment or lesion recurrence were reported. Pain disappeared within 6 weeks of the first cycle for all but one patient. Ossification of the bone lesion was observed for all patients but one, complete for two and partial for the five others.
CONCLUSIONS: Bisphosphonates appear to be an effective option without adverse effects for the non-operative management of symptomatic benign bone tumors.