MEK Inhibition in the Treatment of Congenital Langerhans Cell Histiocytosis: A Case Report and Review of the Literature.

Langerhans cell histiocytosis (LCH) is a histiocytic disorder that predominantly affects young children, with congenital manifestations being exceedingly rare. Here, we report a male infant with congenital LCH harboring a driving mutation within the mitogen-activated protein kinase pathway, specifically MAP2K1 Q56P. First-line use of targeted therapy with oral MEK inhibitor trametinib led to rapid and complete resolution of the infant's widespread cutaneous disease. This patient remains clinically well with normal growth and development and no sign of progressive disease or medication intolerance. This case demonstrates the impact that targeted therapy can have as an alternative to systemic chemotherapy in an age group known to experience more extensive disease.

Treatment of congenital Langerhans cell histiocytosis with cobimetinib.

We report a case of congenital multisystem Langerhans cell histiocytosis with cutaneous and hematopoietic involvement. After the failure of first-line (vinblastine and prednisolone) and second-line (vincristine and cytarabine) therapies, treatment with cobimetinib, a mitogen-activated protein kinase (MEK) inhibitor, led to the remission of disease and a sustained response after 11 months of ongoing treatment. Protein kinase inhibitors targeting BRAF or MEK could represent a promising future therapeutic option, also in children with LCH.

A case report of a blueberry muffin baby caused by congenital self-healing indeterminate cell histiocytosis.

BACKGROUND: Blueberry muffin is a descriptive term for a neonate with multiple purpuric skin lesions. Many causes are known, amongst them life-threatening diseases like congenital infections or leukemia. Indeterminate cell histiocytosis (ICH) is an exceptionally rare cause of blueberry muffin rash. ICH is a histiocytic disorder which can be limited to the skin or can present with systemic involvement. A mutation that has been described in histiocytic disorders is a MAP2K1 mutation. In ICH, this mutation has previously been described in merely one case. CASE PRESENTATION: A term male neonate was admitted to the neonatology ward directly after birth because of a blueberry muffin rash. ICH was diagnosed on skin biopsy. The lesions resolved spontaneously. The patient is currently 3 years old and has had no cutaneous lesions or systemic involvement so far. This disease course is similar to that of the Hashimoto-Pritzker variant of LCH. CONCLUSIONS: ICH can manifest in neonates as resolving skin lesions. It is limited to the skin in most cases, but systemic development is possible. Therefore, it is essential to confirm the diagnosis with a biopsy before the lesions resolve and to monitor these patients closely with routine follow-up.

Congenital Unilesional Cutaneous Langerhans Cell Histiocytosis: A Case Report.

ABSTRACT: Langerhans cell histiocytosis (LCH) is a clonal proliferation of bone-marrow-derived cells, which normally reside as epidermal and mucosal dendritic cells involved in antigen presentation. It is a rare disease more common in children than adults, that is believed to be neoplastic in most cases. The diagnosis is based on clinical and radiological findings in combination with histopathologic, immunophenotypic, or ultrastructural analyses. LCH have a broad spectrum of clinical manifestations, ranging from benign cutaneous lesions to malignant multisystem disease. Based on the extent of involvement at diagnosis, LCH can be divided in single-system LCH when only one organ or system is involved, usually with multiple lesions, and multisystem LCH, when 2 or more organs or systems are involved at diagnosis. One variant of LCH is characterized by congenital isolated cutaneous involvement. It typically manifests at birth or in the postnatal period with a widespread eruption of red-to-brown papulo-nodules or, more uncommonly, a solitary lesion. The overall prognosis for single lesion skin limited LCH is excellent and most lesions spontaneously resolve within 4-18 weeks. Systemic involvement is rare. Skin findings cannot predict systemic disease and obtaining an oncology consultation is recommended for further evaluation. Herein, we present an additional case in a full-term, well-appearing, female infant with an isolated, asymptomatic, ulcerated, papule of the left arm, that was noted at birth.

Remission of Congenital Multi-system Type Langerhans Cell Histiocytosis with Chemotherapy.

Patients with multi-system (MS)-type langerhans cell histiocytosis (LCH) show poor outcomes, especially congenital MS LCH cases were shown in high mortality rate. We experienced a congenital case of MS LCH with high risk organs, who needed intensive respiratory support after birth. Even though intensive chemotherapy was discontinued, this patient's lung LCH lesions gradually became reduced and his respiratory condition recovered; therefore, we restarted and completed maintenance chemotherapy. The patient maintained complete remission for more than 4 years after the end of chemotherapy. Our case suggests that congenital MS LCH even with severe organ involvement can be treated successfully with chemotherapy.

A neonatal pustule:Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) is a rare, clinically heterogeneous disease that most commonly occurs in pediatric populations. Congenital self-limited LCH is a benign variant of LCH. It most commonly presents as a diffuse eruption and reports of single lesion cases are infrequent in the literature. Even in the case of congenital self-limited LCH, there is potential for future multisystem relapse, making long-term follow-up important. We present a case of single lesion self-limited LCH in a full-term male infant with interesting morphology. Physical examination revealed a painless, 6 millimeter, well-demarcated, papule encircled by erythema with central hemorrhage. An infectious workup was negative and a punch biopsy was obtained, which showed a dermal infiltrate of histiocytes consistent with a diagnosis of LCH. The lesion healed without intervention within three weeks. Our case highlights the need for dermatologists to consider LCH in the differential diagnosis for lesions of varying morphology in children, as proper identification is necessary to monitor for multisystem recurrence.

Congenital Langerhans cell histiocytosis presenting in a 27-week-gestation neonate.

Langerhans cell histiocytosis is exceedingly rare in premature infants, and the few cases reported suggest a poor prognosis with systemic involvement. We present a case of Langerhans cell histiocytosis limited to a single cutaneous lesion, presenting in a 27-week-gestation infant, which is the youngest gestational age of reported Langerhans cell histiocytosis cases. The lesion showed spontaneous resolution by 41 weeks corrected gestational age, and systemic involvement was absent, demonstrating a mild course of skin-only Langerhans cell histiocytosis in a premature infant.

Congenital cutaneous Langerhans cell histiocytosis and cutaneous mastocytoma in a child.

Langerhans cell histiocytosis and mastocytoma are clonal disorders of bone-marrow-derived cells, most commonly seen in the pediatric age. Infiltration of mast cells and Langerhans cells in the same lesion has been published before, but, to our knowledge, this is the first time that the occurrence of two mastocytomas and Langerhans cell histiocytosis is reported. It could be hypothesized that both clonal disorders of bone-marrow-derived cells could have a common origin.

Identification of the V600D mutation in Exon 15 of the BRAF oncogene in congenital, benign langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) is a well-known but rare disease that may occur at any age with markedly variable clinical features: self-regressive, localized, multiorgan, aggressive, or fatal outcome. Congenital LCH is rare and often clinically benign. While LCH is characterized by a clonal proliferation of Langerhans cells, its etiology is unknown. Although BRAF V600E mutations were recently identified as a recurrent genetic alteration in LCH cases, the clinical significance of this mutation within the heterogeneous spectrum of LCH is also currently unknown. We studied a cutaneous, benign form of congenital LCH that occurred in a newborn male, without recurrence for 8 years. Histopathologically, the skin lesion excised after birth showed the typical cytologic and immunophenotypic features of LCH. Sequencing analysis of Exon 15 of the BRAF gene revealed the V600D mutation, with an allelic abundance of 25-30%, corresponding to the LCH cells being hemizygous for the mutant allele. BRAF V600E-specific polymerase chain reaction was negative. Our report is the first to identify the rare, variant BRAF V600D mutation in LCH, and provides support for constitutively activated BRAF oncogene-induced cell senescence as a mechanism of regression in congenital, benign LCH. Further, our clinicopathologic findings provide proof for the first time that the V600D mutation can also occur in the absence of ultraviolet light, and can occur in a clinically benign proliferation, similar to the V600E mutation. Additional clinicopathologic studies in larger numbers of LCH patients may be valuable to ascertain the pathophysiologic role of BRAF mutations in LCH.

Congenital self-healing reticulohistiocytosis presented with multiple hypopigmented flat-topped papules: a case report and review of literatures.

Congenital self-healing reticulohistiocytosis, also known as Hashimoto-Pritzker disease, is a single system Langerhans cell histiocytosis that typically presents in healthy newborns and spontaneously regresses. In the present report, we described a 2-month-old Thai female newborn with multiple hypopigmented flat-topped papules without any internal organ involvement including normal blood cell count, urinary examination, liver and renal functions, bone scan, chest X-ray, abdominal ultrasound, and bone marrow biopsy. The histopathology revealed typical findings of Langerhans cell histiocytosis, which was confirmed by the immunohistochemical staining CDla and S100. Our patient's lesions had spontaneously regressed within afew months, and no new lesion recurred afterfour months follow-up.

[Blueberry Muffin Baby and Langerhans' congenital cell histiocytosis]. / Histiocytose langerhansienne congénitale et « Blueberry Muffin Baby ¼

BACKGROUND: Blueberry Muffin Baby is a rare neonatal cutaneous syndrome for purpuric lesions reflective of extramedullary hematopoiesis. Many causes are known, examples are congenital infections, malignancy and hematologic disorders. Langerhans' cell histiocytosis is a clonal proliferation of dendritic histiocytes. This has very rarely been associated with a Blueberry Muffin Baby presentation. CASE REPORT: We report the case of a newborn presenting with Blueberry Muffin Baby syndrome related to congenital Langherans' cell histiocytosis. At birth, he had multiple purpuric lesions on the trunk, limbs and face. Skin biopsy showed a dermal proliferation of histiocytes staining positive for S100 and CD1a. Chest and bone radiographs, and abdominal ultrasound were normal. Skin lesions have resolved in 8 weeks, the patient is in complete remission at 18 months of follow-up. DISCUSSION: A Blueberry Muffin Baby syndrome may reveal neonatal Langerhans' histiocytosis.

Congenital localized cutaneous Langerhans cell histiocytosis in a Holstein calf.

Distinct solitary dermal nodules, either covered by an alopecic, or sometimes ulcerated, epidermis, were noticed on the head of a stillborn Holstein calf. The head was submitted for autopsy, and the nodules were found to consist of homogeneous, diffuse pale-yellow, soft-tissue masses with distinct margins that elevated the epidermis above the adjacent skin. Histologically, the dermal nodules were well-delineated on the deep margin approaching the cutaneous muscle and consisted of perivascular neoplastic infiltrates of round cells that in some places coalesced into sheets that extended into the dermis and subcutis. Neoplastic cells separated adnexa and collagen. Immunohistochemistry revealed intense tumor cell expression of vimentin, Iba1, E-cadherin, and CD204; expression of CD18 was faint. The masses were diagnosed as Langerhans cell histiocytosis. Congenital cutaneous Langerhans cell histiocytosis has not been reported previously in cattle, to our knowledge, and should be included in the differential diagnosis of congenital nodular skin lesions.

Solitary congenital self-healing Langerhans cell histiocytosis: a benign variant of Langerhans cell histiocytosis?

Langerhans cell histiocytosis (LCH) represents a diverse group of diseases with various different clinical presentations and outcomes. We present two cases of solitary CSH-LCH (sCSH-LCH) and highlight certain unique characteristics including the favorable prognosis and lack of documented progression to systemic involvement in reported cases.

Congenital self-healing reticulohistiocytosis: concern for a poor prognosis.

Congenital self-healing reticulohistiocytosis (CSHRH) is a rare type of Langerhans cell histiocytosis with potential for relapse and systemic involvement. Whereas CSHRH was traditionally considered a benign disease, there is an approximately 3 percent risk of mortality and a 10 percent chance of relapse. This article, using an extensive review of cases since Hashimoto and Pritzker first described the condition in 1973, highlights the various presentations of CSHRH and reveals high rates of relapse and systemic involvement in cases that specifically address features of CSHRH occurring within the first year of life. The findings from this review will highlight the importance of considering LCH in the differential diagnosis when evaluating a neonate with congenital skin eruptions. Timely diagnosis of CSHRH and treatment of systemic involvement may decrease the likelihood of adverse outcomes. These patients may require closer follow-up and monitoring than previously recommended, especially in the first year of life when relapses and systemic involvement occur most frequently.

Congenital self-healing reticulohistiocytosis - an important diagnostic challenge.

AIM: To present current and new knowledge on congenital self-healing reticulohistiocytosis, a benign variant of cutaneous Langerhans cell histiocytosis presenting with skin lesions in the neonatal period. METHODS: We describe and photo document two cases of this rare disease and review the literature. RESULTS: Only few newborns have acute access to a neonatal dermatologist, and we demonstrate how the spontaneous cutaneous involution may happen even prior to the first dermatological assessment. As no sole criterion can reliably distinguish the self-healing form from disseminated disease, multidisciplinary assessment and follow-up are essential. CONCLUSION: Our data document how easily the diagnosis congenital self-healing reticulocytosis may be missed and emphasize the importance and value of instant clinical photographing at the neonatal unit and the use of teledermatology whenever congenital self-healing reticulohistiocytosis is suspected.

Is Langerhan cell histiocytosis complicated with hydrops fetalis exclusively lethal in premature neonates?

Langerhans cell histiocytosis is a rare disease and is lethal in premature neonates. A male premature neonate born at gestational 33 weeks presented with generalized vesicles, hydrops fetalis with pleural effusion, bilateral cataracts, and severe respiratory distress syndrome complicated with persistent pulmonary hypertension. Skin biopsy confirmed the diagnosis of Langerhans cell histiocytosis.

A case of congenital solitary Langerhans cell histiocytoma.

A newborn baby boy was referred to the Paediatric Dermatology Unit with a solitary asymptomatic nodule overlying his right nasolabial fold. Complete physical examination, full blood count, serum chemistry, liver function tests and baseline imaging were unremarkable. Histopathological examination showed an atypical dermal infiltrate of mononuclear cells that stained positive with CD1a and S100. A diagnosis of congenital solitary Langerhans cell histiocytoma was made. The lesion completely resolved by 4 months of age. The baby is now 15 months old and repeat systemic evaluation has remained normal.