Eosinophilic granuloma (EG), a subtype of Langerhans cell histiocytosis (LCH), the monostotic form, is a rare condition characterized by a solitary bone lesion. It is even more unusual for this condition to be accompanied by an epidural hematoma (EDH). This case is unique in that it is the first to involve delayed EDH following a seizure. We describe a remarkable example of EG accompanied by an EDH and consider the rarity of this comorbidity. A 32-month-old boy developed a rapidly growing skull mass following a minor head injury. During surgical preparation for a biopsy, the patient experienced a single convulsion. Imaging following the seizure revealed an EDH in the vicinity of the mass. The mass was excised and confirmed to be an EG, but with positive margins. The patient underwent chemotherapy after systemic skeletal evaluation, in accordance with the LCH III protocol established by the Histiocytosis Society. EG is a rare neoplasm that typically presents as a painless growth on the skull that gradually enlarges over time. The correlation between EG and EDH is exceedingly uncommon, with only a few documented cases. This case study underscores the significance of considering EG in the differential diagnosis of an expanding cranium mass, even when associated with EDH. Prompt diagnosis and treatment can prevent serious complications and improve patient outcomes.

Langerhans cell histiocytosis (LCH) is a rare condition in adults, especially when it is limited to a single area of the skull, known as solitary calvarial involvement. In this case report, we present a unique instance of LCH affecting the parietal bone with a pus-draining fistula. This is a rare and unusual presentation at this location, which has been scarcely reported in medical literature. A 30-year-old woman with no prior comorbidity presented with complaints of headache that persisted for a year. She also had swelling on her scalp and a yellowish discharge for 3 weeks, but no neurological problems were observed. Radiology revealed thinning of the calvaria, with ragged margins along the inner table, multiple focal erosions, and involvement of overlying soft tissue and bony sequestrum. The patient underwent biparietal craniotomy and excision of the lesion. The histopathology report showed LCH. After 8 months of follow-up, there was no recurrence. The management of solitary calvarial involvement by LCH with masquerading presentation as a scalp infection can be achieved through complete excision of the lesions, resulting in a favorable outcome.

Histiocytosis comprises a heterogeneous group of inflammatory diseases whose main cellular components are dendritic cells and macrophages. The inflammatory infiltrate can affect the skin and other organs and the clinical outcome varies from mild to fatal depending on the involved cell subset and multisystemic compromise. Delay in diagnosis may occur due to its non-specific presentation and to a low suspicion on the part of the clinician. We report the case of an infant who despite multiple consultations with nonspecific but characteristic symptoms of the disease was only finally diagnosed thanks to histopathological findings.
La histiocitosis de células de Langerhans comprende un grupo heterogéneo de enfermedades inflamatorias cuyos principales componentes celulares son las células dendríticas y los macrófagos. El infiltrado inflamatorio puede afectar la piel y otros órganos, y el resultado clínico varía de leve a letal, dependiendo del subconjunto de células involucradas y el compromiso multisistémico. La demora en el diagnóstico puede ocurrir debido a su presentación inespecífica y a que los médicos tratantes no suelen sospecharla. Se reporta el caso de una lactante mayor a la cual, a pesar de múltiples consultas con síntomas inespecíficos pero característicos de la enfermedad, solamente se le pudo hacer el diagnóstico gracias a los hallazgos histopatológicos.

Smoking-associated interstitial lung disease manifests as several heterogeneous disorders involving the airways, pleura, and lung parenchyma with various radiological patterns. The clinical history, radiologic, and pathologic findings are important to distinguish these more uncommon diseases. A multidisciplinary approach is recommended for diagnosis and to manage these conditions appropriately.
This review provides an overview of the epidemiology, risk factors, pathogenesis, clinical features, diagnosis, and treatment of acute eosinophilic pneumonia, e-cigarettes, or vaping associated lung injury, respiratory bronchiolitis interstitial lung disease, desquamative interstitial pneumonitis, pulmonary Langerhans cell histiocytosis, idiopathic pulmonary fibrosis, and combined pulmonary fibrosis emphysema.
Cigarette smoking is associated with a variety of pathologic conditions that affect the airways and lungs. E-cigarette use and vaping present new challenges to the clinician. Consensus between the clinical, radiographic, and pathologic findings is important in identifying and differentiating between the various entities to properly diagnose smoking-related interstitial lung diseases discussed in this review.

Bone necrosis of the jaw is a serious condition with a broad differential diagnosis of pathologies such as cutaneous histiocytosis, bone metastases or malignant tumours. In addition to the most common cause, medication related osteonecrosis of the jaw (MRONJ), one must consider a number of other causes, such as histiocytosis. Langerhans cell histiocytosis (LCH) is a histiocytic disorder with a large spectrum of clinical manifestations and with possible involvement of a variety of organs. This case shows the importance of an early detection of this rare disease in order to prevent further spreading. Even if an initial diagnosis in the oral cavity is rare, dentists should be aware of this disease.
The presented case describes a patient who was referred for evaluation and treatment due to exposed bone and extensive osteolysis in the region of the upper and lower jaw. After biopsy and diagnosis of LCH, the patient was treated with systemic therapy, achieved remission and is disease free after a 2 year of follow up.
This case report illustrates that when dealing with unclear osteolytic changes of the jawbone, Langerhans cell histiocytosis must be taken into consideration in the differential diagnosis and biopsy must be performed in case of suspicion.

UNASSIGNED: Langerhans cell histiocytosis (LCH) is a rare histiocytic proliferative disorder of unknown etiology and mainly affects young children. The histological feature is granuloma-like proliferation of langerhans-type dendritic cells. Although the possible role of viruses such as Epstein-Barr virus (EBV, Human Herpes virus -4), Human Herpes virus-6 (HHV-6), Herpes Simplex virus (HSV) types 1 and 2 and Cytomegalovirus (CMV, Human Herpes virus-5) is suggested in the pathogenesis of LCH by some investigators, its exact pathophysiology has not been cleared yet. In this study, we investigated the presence of HSV types 1 and 2 in Iranian children with LCH.
UNASSIGNED: In this retrospective study, we investigated the prevalence of presence of HSV types 1 and 2 (in 30 patients with LCH), using paraffin-embedded tissue samples and 30 age and tissue-matched controls (operated for reasons other than infectious diseases) from the Department of Pediatric Pathology, Tehran, Iran, by nested Polymerase Chain reaction method. No ethical issues arose in the study, because only the pathology reports were reviewed and patients were anonymous.
UNASSIGNED: We failed to find HSV types 1 and 2 DNA in any of the 30 patients with LCH or the control group.
UNASSIGNED: According to our findings, HSV types 1 and 2 do not appear to have any etiologic role in the pathogenesis of LCH in Iranian children. These results are in accordance with previous investigations with negative findings.

Congenital self-healing reticulohistiocytosis (CSHRH) is a rare, cutaneous, self-limited form of Langerhans cell histiocytosis. Whereas multiple lesions are common, a solitary lesion is rare. A 14-day-old neonate presented with a solitary, 5-mm, oval, reddish, and eroded papule with crust on the left thigh that had existed since birth. No systemic involvement was found. Histopathology revealed dense infiltration of large histiocytes with scattered eosinophils and lymphocytes in the dermis. Immunohistochemistry showed S-100 and CD1a positivity. Two months later, the skin lesion involuted spontaneously, without evidence of recurrence and extracutaneous involvement. On the basis of the characteristic clinical course and typical histopathological findings, a diagnosis of solitary CSHRH was made.