Juvenile xanthogranuloma manifesting with LCH-associated neurodegenerative disease-like radiological findings

Here, we describe two patients with juvenile xanthogranuloma (JXG) manifesting with Langerhans cell histiocytosis (LCH)-associated neurodegenerative disease (ND)-like radiological findings. One patient showed typical radiological abnormalities at onset, which worsened with progressing central nervous system symptoms 7 years after LCH-oriented chemotherapy. Another showed spontaneous regression of clinical symptoms, with a transient radiological change 1 year after salvage chemotherapy for recurrence of JXG. These data regarding JXG-associated ND will facilitate future investigation of the disease, as well as development of therapeutic interventions.

Oral sirolimus for the treatment of juvenile xanthogranuloma: Report of two pediatric cases

Juvenile xanthogranuloma (JXG) with extensive cutaneous or visceral organ involvement is often associated with high morbidity and treatment commonly involves surgical excision, radiotherapy, systemic steroids, or chemotherapy. Sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, is an oral antitumor and immunosuppressive therapy used to treat various neoplastic disorders, including histiocytic disorders. We report two pediatric cases of JXG successfully treated with oral sirolimus monotherapy, and postulate that sirolimus may induce rapid disease resolution and long-term remission for patients with both skin-limited and multisystemic JXG. Our findings warrant further investigation of the relationship between the mTOR pathway and JXG.

Circulating senescent myeloid cells infiltrate the brain and cause neurodegeneration in histiocytic disorders

Neurodegenerative diseases (ND) are characterized by progressive loss of neuronal function. Mechanisms of ND pathogenesis are incompletely understood, hampering the development of effective therapies. Langerhans cell histiocytosis (LCH) is an inflammatory neoplastic disorder caused by hematopoietic progenitors expressing mitogen-activated protein kinase (MAPK)-activating mutations that differentiate into senescent myeloid cells that drive lesion formation. Some individuals with LCH subsequently develop progressive and incurable neurodegeneration (LCH-ND). Here, we showed that LCH-ND was caused by myeloid cells that were clonal with peripheral LCH cells. Circulating BRAFV600E+ myeloid cells caused the breakdown of the blood-brain barrier (BBB), enhancing migration into the brain parenchyma where they differentiated into senescent, inflammatory CD11a+ macrophages that accumulated in the brainstem and cerebellum. Blocking MAPK activity and senescence programs reduced peripheral inflammation, brain parenchymal infiltration, neuroinflammation, neuronal damage and improved neurological outcome in preclinical LCH-ND. MAPK activation and senescence programs in circulating myeloid cells represent targetable mechanisms of LCH-ND.

MUM1/IRF4 immunolabeling of neoplastic Langerhans histiocytes in a putative case of canine Langerhans cell histiocytosis

Langerhans cell histiocytosis is a systemic histiocytic proliferative disease with cutaneous manifestations which is well described in human medical literature and has relatively recently been reclassified as a neoplastic disorder. The diagnosis of canine Langerhans cell histiocytosis has been proposed in the veterinary literature to refer to a histiocytic proliferative disease in the dog with clinical and histopathologic features that mirror the human disease. However, reports that invoke this diagnosis are rare and often lack complete diagnostic characterization. This case report presents an extensive diagnostic investigation of a putative case of Langerhans cell histiocytosis in a 3-year-old male castrated Golden Retriever dog, including gross, cytologic, histopathologic, and immunohistochemical findings. Furthermore, we document that canine LCH may have positive immunolabeling for the transcription factor multiple myeloma oncogene 1/interferon regulatory factor 4 (MUM1/IRF4), which is classically used for the diagnosis of canine plasma cell neoplasms.

A meta-analysis of cases of Rosai Dorfman disease reported on the African continent and a description of two cases from a tertiary academic hospital in Johannesburg, South Africa

Rosai-Dorfman-Destombes disease (RDD) is a rare non-Langerhans cell histiocytosis characterized by the accumulation of activated histiocytes within affected tissues. The original haematopathological description of RDD has links to the late South African born haematopathologist, Ronald Dorfman, with a descriptive account of two cases of the disease treated at Chris Hani Baragwanath Academic Hospital are described herein. Alongside the two case descriptions is a meta-analysis of 149 published cases from the African continent. Sequential literature searches were performed on Google Scholar and PubMed with the search terms "sinus histiocytosis with massive lymphadenopathy", "Rosai-Dorfman disease", "Rosai-Dorfman Destombes" and "lymphadenopathy" together with the name of each individual country on the African continent, from Algeria to Zimbabwe. All possible cases of RDD reported in published literature from Africa were captured on a Microsoft Excel spreadsheet recording details, where available, of demographics, nodal (nodal groups) or extra-nodal disease as well as treatment. Of the 54 African countries on the continent, published data was available from half of these countries (n=27). Nigeria (35), Tunisia (25) and South Africa (23) contributed the majority of cases for data collection with a clear paucity of reportable information available from Central Africa. Of the 149 cases from the African continent, the majority were from patients aged ten years and younger with a decrease in reported cases in patients with increasing age. The mean age at diagnosis was 25.66 years [95% CI: 21.81-29.51] with a median age of diagnosis of 24.5 years. The youngest patient in the series was 3 months old and the oldest patient aged 72 (range 71.75 years, IQR 31). The cases reported were fairly split between males and females with a male-to-female ratio of 1.07: 1. HIV seropositivity was reported in seven patients (4.8%) and no HIV results were available in 104 patients (71.2%). Disease presentation was split between nodal disease in 43% of patients (n=64), Extra nodal (EN) disease in 32.9% (n=32), mixed (nodal/EN) disease in 11.4% (n=17) and unknown in 12.8% (n=19). Fever was present in 18.1% (n=27) of cases. Hepatic enlargement was noted in nine patients (6%) and splenic enlargement in four patients (2.7%). Commonly ascribed sites of EN disease, in descending order, were skin and soft tissue, ocular, ear/nose/throat (ENT), abdominal organ(s), bone, lung/pleura, brain parenchyma (including dura), endocrine glands, spine, breast, pericardium, pseudotumour formation (unspecified site), joint(s), peripheral nerves and genitourinary tract disease. The upfront administration of glucocorticosteroids was seen in the majority of cases. Rosai-Dorfman-Destombes, although a rare disorder, should be considered as a differential diagnosis in patients with massive bilateral cervical lymphadenopathy and is confirmed with accompanying pathological changes on microscopic and immunohistochemical examination of biopsy specimens. The role of infection, particularly HIV infection, is considered to be a possible contributor to the pathogenesis of RDD and HIV testing in patients from areas of high HIV endemicity with co-existing RDD should be undertaken. Consideration for mycobacterium tuberculosis infection in patients with generalized significant lymphadenopathy still remains an important differential for massive lymphadenopathy and requires confirmation by appropriate microbiological investigations. The treatment landscape in RDD is limited in many resource-poor settings, with the upfront use of glucocorticosteroids employed routinely in the majority of cases.

Eruptive agminated nevi in a successfully treated Langerhans cell histiocytosis patient

A 7-year-old girl with a history of Langerhans cell histiocytosis (LCH), in remission, presented with the sudden appearance of multiple, agminated nevi. Skin biopsy revealed a benign junctional nevus, without recurrence of LCH. Subsequent immunohistochemical testing of both the skin and iliac wing biopsies demonstrated a BRAF V600E mutation. MAPK pathway mutations have been implicated in both LCH and nevogenesis.

Unilesional granulomatous pigmented purpuric dermatosis in a 7-year-old boy

Granulomatous pigmented purpuric dermatoses (PPD) are rarely reported. We present a case of granulomatous PPD in a 7-year-old boy, one of only two pediatric cases with reported solitary disease. The pathogenesis of unilesional granulomatous PPD may be different from the more commonly described multifocal/widespread disease variant.

Juvenile xanthogranulomas: Examining single, multiple, and extracutaneous presentations

BACKGROUND

Juvenile xanthogranuloma (JXG) is a non-Langerhans cell histiocytosis characterized by yellowish papules in the skin. JXGs most often occur in infancy or early childhood and are typically solitary and asymptomatic, often regressing after several years. While JXGs predominantly occur on the skin, extracutaneous JXGs also exist.

AIMS

In this paper, we review the literature on single, multiple, and visceral JXGs and provide recommendations on monitoring and work-up.

MATERIALS & METHODS

A literature review was conducted with the PubMed database using selective search terms for single, multiple, ocular, and visceral lesions as well as NF1/JMML.

RESULTS / DISCUSSION

JXG is typically a self-limited disorder if lesions are cutaneous and singular. While rare, JXGs may manifest as multiple and extracutaneous lesions. Further screening and referral to specialists may be warranted in these cases based on age and extent of involvement.

CONCLUSION

Our review demonstrates common presentations of single, multiple, and extracutaneous lesions in addition to those that occur with NF1 and JMML. We suggest patients be evaluated on a case-by-case basis by a dermatologist and referred to specialists as appropriate.

Homozygosity for a novel large deletion in SLC29A3 in a patient with H syndrome

H syndrome (OMIM 6027820) is a novel form of histiocytosis affecting multiple organs with peculiar cutaneous manifestations. It is an autosomal recessive genodermatosis caused by pathogenic mutations in SLC29A3 that encodes the human equilibrative nucleoside transporter, hENT3. The cutaneous manifestations can mimic other sclerodermoid conditions. We present a 15-year-old boy diagnosed with H syndrome with typical clinical features and homozygosity for a novel pathogenic mutation.

Cytological diagnosis of juvenile xanthogranuloma: A rare histiocytic disorder

Juvenile xanthogranuloma (JXG) is a rare type of non-Langerhan cell histiocytic disorder, which is mostly confined to skin of head and neck. It is a self-limiting benign condition, which does not require surgery. We present a case of 8-month-old girl child with multiple yellowish brown colored papules over scalp, face, and neck. A clinical diagnosis of cutaneous mastocytosis was made. Fine-needle aspiration cytology (FNAC) smears showed foamy macrophages along with mixed inflammatory infiltrate and few touton giant cells. A diagnosis of JXG was rendered which was confirmed on histopathology and immunohistochemistry.Juvenile xanthogranuloma can be diagnosed on FNAC based on its characteristic cytologic features; however, it requires a high index of suspicion by cytopathologist. Cytological diagnosis of JXG can save the patient from unnecessary surgical biopsy or excision.

Treatment of benign cephalic histiocytosis with topical 1% rapamycin ointment

We report a pediatric case of extensive, progressive benign cephalic histiocytosis (BCH) involving the face, trunk, and extremities with response of facial lesions to treatment with topical 1% rapamycin. A split-face model was used to demonstrate improvement on the treated side versus the untreated side. After physician and parental perception of effectiveness, based in part on photodocumentation, subsequently both cheeks were treated with continued improvement.

Cutaneous Langerhans cell histiocytosis presenting with hypopigmented lesions: Report of two cases and review of literature

Langerhans cell histiocytosis is a rare group of disorders that results from the abnormal proliferation and accumulation of dendritic-derived cells in various organs of the body, such as the skin and bones. Hypopigmented macules are a rare cutaneous presentation of Langerhans cell histiocytosis that may pose a diagnostic dilemma when no other findings of Langerhans cell histiocytosis are present at the time of examination. We present 2 cases of the hypopigmented variant of Langerhans cell histiocytosis, including a case with histopathologic features of regression, and a review of the literature. These cases highlight the importance of including Langerhans cell histiocytosis in the differential diagnosis of an infant with hypopigmented macules and papules.

Juvenile xanthogranuloma with angiomatous appearance and a peculiar immunophenotype

Juvenile xanthogranuloma is the most common form of non-Langerhans cell histiocytosis in childhood. The clinical differential diagnosis of a solitary juvenile xanthogranuloma includes molluscum contagiosum, Spitz nevus, and melanoma. Lesions larger than 2 cm in diameter may be misdiagnosed as hemangiomas, but this is not typical of smaller juvenile xanthogranuloma. We report a case of solitary juvenile xanthogranuloma in a 10-year-old boy with angiomatous appearance and peculiar immunophenotype.

NB-UVB phototherapy for generalized granuloma annulare

Granuloma annulare (GA) is a benign, usually self-limited, granulomatous skin disease of unknown etiology. The generalized form of the disease shows a more chronic, relapsing course, rare spontaneous resolution, and poorer response to therapy. Psoralen plus UVA phototherapy has been reported to be effective for GA. However, little is known regarding the efficacy of narrowband UVB phototherapy. Our goal was to determine the efficacy of NB-UVB phototherapy in generalized GA. We carried out a retrospective study of patients with generalized GA treated with NB-UVB phototherapy over a period of 3 years. On completion of treatment, outcome was assessed as complete response (complete clearance of the lesions), partial response (>50% clearance of the lesions), and poor response (<50% clinical response). Therapy was stopped if no improvement was seen after 20 treatments. Thirteen patients were included in the study. 54% of patients treated with NB-UVB had a complete/partial response by the end of the treatment period. NB-UVB phototherapy was well-tolerated, with no serious adverse effects. NB-UVB phototherapy is effective in a substantial portion of patients with generalized GA. To determine the true efficacy of this therapeutic modality, a prospective study comparing it to PUVA is warranted.

Haemophagocytic syndrome in intensive care: The great pretender

The haemophagocytic syndrome is a unique disease process in which the dysregulation of the patient's immune system leads to an inflammatory storm which rapidly ravages through multiple organ systems, generating life-threatening end-organ dysfunction. Since it usually mimics other conditions frequently encountered in the critical care population - most notably septic shock - its diagnosis is elusive and the condition remains under-recognized and under-reported. We present a concise review of the pathophysiology and clinical features of the heamophagocytic syndrome and discuss the main diagnostic and therapeutic issues relevant to the management of this condition in the critically ill patient. Increasing awareness about the haemophagocytic syndrome amongst intensive care physicians will facilitate earlier recognition and timely management.