Introduction: Arginine vasopressin (AVP) deficiency is an uncommon but important presentation of infiltrative hypothalamic– pituitary disorders. In adults, isolated AVP deficiency with pituitary stalk thickening is diagnostically challenging, especially in the absence of systemic disease. Langerhans cell histiocytosis (LCH) is a rare cause and may precede systemic involvement by several years. Case: We report a 42-year-old male who presented in 2017 with polyuria and polydipsia, with urine output of up to 10 L/ day. AVP deficiency was confirmed by the water deprivation test, and desmopressin was initiated. Initial pituitary magnetic resonance imaging (MRI) was normal, baseline anterior pituitary hormonal evaluation was unremarkable, and contrast-enhanced computed tomography (CECT) of the thorax and abdomen showed no abnormalities. Repeat pituitary MRI 1 year later demonstrated loss of the posterior pituitary bright spot with pituitary stalk thickening. In the absence of systemic involvement, a presumptive diagnosis of lymphocytic hypophysitis was made, and pituitary biopsy was deferred due to the high procedural risk. Serial pituitary MRIs over the following years showed persistent infundibular thickening and continued absence of the posterior pituitary bright spot, without interval progression or development of additional hormonal deficiencies. The patient remained clinically stable until June 2024, when new-onset left hip pain prompted MRI, revealing a heterogeneous mass involving the femoral neck and intertrochanteric region with a pathological fracture. Histopathological examination following wide resection confirmed LCH, with negative BRAF V600 mutation. Postoperative PET scan revealed a multisystem disease involving the skeleton, lymph nodes, spine, and gastrointestinal tract, with no bone marrow involvement. He subsequently completed six cycles of intravenous methotrexate and cytarabine. Conclusion Adult-onset AVP deficiency may be the earliest manifestation of occult multisystem Langerhans cell histiocytosis. This case highlights the importance of longterm follow-up and reconsideration of the initial diagnosis when new systemic features emerge.
Histiocytosis, Langerhans-Cell

Introduction: Langerhans cell histiocytosis (LCH) is a clonal proliferative disorder of langerin-positive histiocytes. Endocrine involvement most frequently manifests as central diabetes insipidus or secondary hypothyroidism, caused by infiltration of the hypothalamic-pituitary axis. Conversely, direct infiltration of the thyroid gland leading to primary hypothyroidism is an exceptionally rare clinical entity, particularly when presenting concurrently with central disease. Case: A 21-year-old female with known right otic and multisystem LCH presented with septic shock secondary to a right ear abscess accompanied by polyuria and polydipsia. Physical examination revealed a palpable goiter. Clinical and biochemical evaluation confirmed central diabetes insipidus with associated anterior hypopituitarism (low adrenocorticotropic hormone, follicle-stimulating hormone, and luteinizing hormone). However, concurrent thyroid function tests demonstrated overt primary hypothyroidism, evidenced by an appropriately elevated thyroid-stimulating hormone (26.19 mIU/L) and low free T4 (5.47 pmol/L), rather than the anticipated secondary hypothyroidism. Neck ultrasound showed diffuse thyroid enlargement with heterogeneous echotexture. Crucially, anti-thyroid peroxidase and anti-thyroglobulin antibodies were both negative, rendering Hashimoto’s thyroiditis highly unlikely. Although the patient declined confirmatory fine-needle aspiration, the constellation of a palpable goiter, characteristic ultrasonographic findings, negative autoimmunity, and active multisystem disease strongly supported a diagnosis of direct histiocytic infiltration of the thyroid gland. She was initiated on appropriate glucocorticoid coverage and subsequent levothyroxine replacement, alongside systemic intravenous cytarabine. Conclusion This case highlights a rare, mixed endocrine profile in multisystem LCH, demonstrating that pituitary and direct end-organ infiltration can coexist. Hypothyroidism in LCH patients with established central diabetes insipidus should not be reflexively assumed to be central in origin. A comprehensive diagnostic workup, including autoantibody screening, ultrasound, and ideally histopathological confirmation, is essential to accurately identify primary endocrine failure and guide appropriate clinical management in these complex cases.
Histiocytosis, Langerhans-Cell ; Hypothyroidism ; Pituitary Gland

OBJECTIVE

To present a case of Langerhans cell histiocytosis mimicking bilateral otitis media and acute mastoiditis in a one-year-old girl, and to discuss the clinical presentation, diagnostic dilemma, management and prognosis of this disease.

Design: Case Report

Setting: Tertiary Private Teaching Hospital

Patient: One

A one-year-old girl with a three-month history of bilateral otorrhea, post-auricular lymphadenopathies and dermatitits unresponsive to multiple courses of antibiotics, developed osseous and soft tissue destruction around the temporal and occipital bones. Her multiple progressive symptoms eventually led to the diagnosis of Langerhans cell histiocytosis.

Langerhans cell histiocytosis is a multifocal disease that can present with ear symptoms and can cause management dilemmas. It may mimic acute or chronic infections of the ear and should be suspected when extensive bone erosion is present.

A 4-year-old boy was admitted to the hospital with a 3-day history of rash and intermittent abdominal pain, during which abnormal results from routine blood tests were discovered. Initially, he presented with acute jaundice hepatitis and pancytopenia. The patient's condition progressed rapidly, with recurrent fever, worsening jaundice of the skin and sclera, and progressively worsening hepatosplenomegaly. Liver function impairment and bone marrow failure continued to deteriorate, while cytokine levels continued to rise. After excluding infections, autoimmune diseases, tumors, genetic metabolic disorders, and toxicities, the patient was diagnosed with hepatitis-associated aplastic anemia (HAAA) complicated by hemophagocytic lymphohistiocytosis (HLH). Following treatment with corticosteroids, plasma exchange, intravenous immunoglobulin, and liver protection therapy, the patient's symptoms partially alleviated. Aplastic anemia complicated by HLH is relatively uncommon, and HAAA complicated by HLH is even rarer, often presenting insidiously and severely. This paper presents a case of HAAA complicated by HLH and summarizes previously reported cases in the literature, providing references for the early diagnosis and treatment of this condition.
Humans ; Lymphohistiocytosis, Hemophagocytic/therapy* ; Male ; Anemia, Aplastic/complications* ; Child, Preschool ; Hepatitis/complications*

OBJECTIVES: To study the clinical characteristics, efficacy, and prognosis of pediatric Langerhans cell histiocytosis (LCH). METHODS: A retrospective analysis was conducted on 72 children with newly diagnosed LCH. RESULTS: The median age of the 72 children was 5 years (range: 0-14 years), with skull involvement being the most common (56 cases, 77.8%). The BRAF-V600E mutation was not associated with clinical characteristics, efficacy, or prognosis (P>0.05). The 5-year overall survival rate was 91.6%±4.2%, and the 5-year event-free survival (EFS) rate was 67.5%±5.8%. The 6-week chemotherapy response rate and 5-year EFS rate were lower in the risk organ involvement group compared to the no risk organ involvement group (P<0.05). The five-year overall survival rates for the group with multi-system involvement and the group with platelet count ≥450×10⁹/L were respectively lower than those for the single-system involvement group and the group with platelet count <450×10⁹/L (P<0.05). Risk organ involvement is an independent risk factor for 5-year EFS (P<0.05). CONCLUSIONS Skull is the most commonly affected site in pediatric LCH. The BRAF-V600E mutation is not related to clinical characteristics, efficacy, or prognosis. Elevated platelet count, risk organ involvement, and multisystem involvement are associated with poor prognosis, with risk organ involvement being an independent risk factor for 5-year EFS.
Humans ; Histiocytosis, Langerhans-Cell/therapy* ; Child, Preschool ; Child ; Male ; Infant ; Female ; Adolescent ; Retrospective Studies ; Proto-Oncogene Proteins B-raf/genetics* ; Prognosis ; Infant, Newborn ; Mutation

The patient was a girl, aged 10 years, who was admitted due to fever for 5 days and pancytopenia in peripheral blood for 2 days. Bone marrow examination showed the presence of phagocytic activity, and peripheral blood tests showed pancytopenia, an increase in ferritin, a reduction in fibrinogen, increases in triglyceride and sCD25, and a reduction in natural killer cell activity, which led to the diagnosis of hemophagocytic lymphohistiocytosis (HLH). On the day of admission, the child developed convulsions and rapidly progressed to refractory status epilepticus, which was consistent with the manifestations of febrile infection-related epilepsy syndrome. HLH was controlled after active immunotherapy, with the sequela of refractory epilepsy, and her cognitive function was essentially within normal limits. This article reports the condition of febrile infection-related epilepsy syndrome caused by HLH for the first time in China, in order to improve the awareness of this disease among clinicians.
Humans ; Lymphohistiocytosis, Hemophagocytic/complications* ; Female ; Child ; Epilepsy/etiology* ; Fever/etiology* ; Epileptic Syndromes/etiology*

<b>b>This report describes a case of adult temporal bone Langerhans cell histiocytosis（LCH） that presented as posterior canal dehiscence syndrome（PCDS）. The patient initially presented with vertigo, tinnitus, and hearing loss. Computed tomography（CT） revealed erosive changes in the mastoid and posterior semicircular canal. After the operation, the patient's hearing and vestibular symptoms disappeared and postoperative recovery was favorable. Adult LCH is relatively rare, and this case serves as an example to discuss the clinical features and treatment options of this disease, followed by a literature review.
Humans ; Histiocytosis, Langerhans-Cell/complications* ; Semicircular Canal Dehiscence/etiology* ; Temporal Bone/pathology*

Langerhans cell histiocytosis of bone is a rare tumor disease characterized by the large accumulation of CD1a⁺ and CD207⁺ dendritic cells in tissues of unknown cause.It mainly occurs in children aged 1-4 years old,with incidences of 4-6 per million in children and 1-2 per million in adults.Due to its low incidence,diverse clinical manifestations,and no obvious specificity of imaging manifestations,the definitive diagnosis and early treatment of this type of tumor are challenging.In this paper,we report 8 cases of Langerhans cell histiocytosis of bone and review the relevant literature published in the past five years to summarize the clinical characteristics,pathological features,diagnosis,treatment,and prognosis of this disease.
Humans ; Bone Diseases/therapy* ; Histiocytosis, Langerhans-Cell/therapy*

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a syndrome characterized by extreme immune activation, resulting in pathologic inflammation that may be life-threatening. Early recognition is crucial since survival largely depends on early initiation of treatment which utilizes a combination of chemotherapy, immunotherapy and in some cases even bone marrow transplantation. OBJECTIVES: This study aims to describe the clinical characteristics, treatment received and outcome of patients diagnosed with HLH at the Philippine Children’s Medical Center from 2004 to 2017. MATERIALS AND METHODS: A retrospective analysis of records of children 0-18 years of age diagnosed with HLH from January 2004 to December 2017 was done. RESULTS: A total of 39 patients were included in the study which gave an incidence of 1.22 per 3000 patients admitted under 18 years of age. There were 29 males (74.4%) and 10 females (25.6%) with a male to female ratio of 2.9:1 Mean age was 6.12 ± 3.89 years. The average time from initial presentation to diagnosis was 6 weeks and 2 days. The most commonly seen clinical and laboratory features observed in these patients were fever (100%), splenomegaly (71.8%), anemia (87.17%), thrombocytopenia (79.48%) and hypertriglyceridemia (69.23%). Only 5 patients were confirmed to be familial HLH with 3 having XLP gene mutation, and one each having syntaxin and perforin gene mutations. Majority of patients received a combination of treatment based on the HLH 2004 regimen while almost one third only received antibiotics. Only 23% of patients survived during the study period and all but one of these patients received drug combinations based on the HLH 2004 protocol. CONCLUSIONS AND RECOMMENDATIONS HLH is a rare but important condition that must be recognized early and treated appropriately to optimize survival. The mortality rate of 39 patients seen in this institution is high. There is a need to better utilize the diagnostic criteria of the disease and to employ a more uniform treatment strategy. Increasing awareness among health care personnel can also improve case finding, characterization and treatment.
Human ; Male ; Female ; Adolescent: 13-18 Yrs Old ; Lymphohistiocytosis, Hemophagocytic ; Philippines

Langerhans Cell Histiocytosis (LCH) is a rare disorder characterized by the abnormal proliferation of histiocytes, predominantly affecting the bones and skin. However, it can also involve the bone marrow, liver, spleen, lungs, pituitary gland, central nervous system, and other organs. The disorder is named for the neoplastic cells that resemble dendritic Langerhans cells found in the skin and mucosa.

We present the case of a 2-year-old Filipino female diagnosed with recurrent LCH, highlighting the diagnostic challenges and therapeutic interventions encountered. The patient initially presented with characteristic papules and plaques indicative of LCH. Initial treatment involved multi-agent chemotherapy, which resulted in significant clinical improvement. However, following the cessation of therapy, the patient experienced recurrence of symptoms, necessitating reevaluation. A skin punch biopsy confirmed the diagnosis of LCH, reinforcing the decision to reinitiate chemotherapy. Complications arose during treatment, including febrile neutropenia, which required hospitalization and adjustments to the management plan. After completing the chemotherapy cycles, the patient demonstrated marked clinical improvement, with the resolution of systemic symptoms and a reduction in the severity of cutaneous lesions.

This case underscores the complexities in managing recurrent LCH in pediatric patients. A comprehensive diagnostic evaluation, vigilant monitoring for treatment-related complications, and prompt therapeutic interventions are critical for achieving optimal outcomes. Effective management requires a multidisciplinary approach to address the unique challenges presented, ensuring timely interventions to improve patient outcomes.