Langerhans cell histiocytosis associated with myelodysplastic syndrome in adults

Cutaneous Manifestations of Myeloid Neoplasms Exhibit Broad and Divergent Morphologic and Immunophenotypic Features but Share Ancestral Clonal Mutations With Bone Marrow

In this study, we performed a comprehensive molecular analysis of paired skin and peripheral blood/bone marrow (BM) samples from 17 patients with cutaneous myeloid or cutaneous histiocytic-dendritic neoplasms. The cutaneous manifestations included 10 patients with cutaneous acute myeloid leukemia (c-AML), 2 patients with full or partial Langerhans cell differentiation, 2 patients with blastic plasmacytoid dendritic cell neoplasms (BPDCN), 1 patient with both Langerhans cell differentiation and BPDCN, and 2 patients with full or partial indeterminate dendritic cell differentiation. Seven of the 10 c-AML patients (70%) exhibited concurrent or subsequent marrow involvement by acute myeloid leukemia, with all 7 cases (100%) demonstrating shared clonal mutations in both the skin and BM. However, clonal relatedness was documented in one additional case that never had any BM involvement. Nevertheless, NPM1 mutations were identified in 7 of the 10 (70%) of these c-AML cases while one had KMT2A rearrangement and one showed inv(16). All 3 patients (100%) with Langerhans cell neoplasms, 2 patients with BPDCN (100%), and one of the 2 patients (50%) with other cutaneous dendritic cell neoplasms also demonstrated shared mutations between the skin and concurrent or subsequent myeloid neoplasms. Both BM and c-AML shared identical founding drivers, with a predominance of NPM1, DNMT3A, and translocations associated with monocytic differentiation, with common cutaneous-only mutations involving genes in the signal transduction and epigenetic pathways. Cutaneous histiocytic-dendritic neoplasms shared founding drivers in ASXL1, TET2, and/or SRSF2. However, in the Langerhans cell histiocytosis or histiocytic sarcoma cases, there exist recurrent secondary RAS pathway hits, whereas cutaneous BPDCN cases exhibit copy number or structural variants. These results enrich and broaden our understanding of clonally related cutaneous manifestations of myeloid neoplasms and further illuminate the highly diverse spectrum of morphologic and immunophenotypic features they exhibit.

Clinical, Histopathological and Molecular Spectrum of Cutaneous Lesions in Myelodysplastic Syndrome and Myeloproliferative Neoplasms (MDS/MPN): An Integrative Review

Myeloid neoplasms and acute leukemias include different entities that have been recently re-classified taking into account molecular and clinicopathological features. The myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN) category comprises a heterogeneous group of hybrid neoplastic myeloid diseases characterized by the co-occurrence of clinical and pathological features of both myelodysplastic and myeloproliferative neoplasms. The most frequent entity in this category is chronic myelomonocytic leukemia (CMML) which is, after acute myeloid leukemia (AML), the main myeloid disorder prone to develop cutaneous manifestations. Skin lesions associated with myelodysplastic and myeloproliferative neoplasms include a broad clinical, histopathological and molecular spectrum of lesions, poorly understood and without a clear-cut classification in the current medical literature. The aim of this review is to describe and classify the main clinical, histopathological and molecular patterns of cutaneous lesions in the setting of MDS/MPN in order to improve the diagnostic skills of the dermatologists, hematologists and pathologists who deal with these patients.

Spectrum of second primary malignancies and cause-specific mortality in pediatric and adult langerhans cell histiocytosis

With the advent of targeted therapeutics in Langerhans cell histiocytosis (LCH), there is a growing survivor population that might be at risk for late mortality from non-LCH causes, including second primary malignancies (SPMs). We undertook a large study using the Surveillance, Epidemiology, and End Results (SEER) database to evaluate the patterns of SPMs and cause-specific mortality among individuals with LCH (2000-2016) from the US. We found an increased risk of SPMs in the cohort (standardized incidence ratio [SIR] 2.07). The pediatric group was at a high risk of developing Hodgkin lymphoma (SIR 60.93) and non-Hodgkin lymphoma (SIR 60.88). People with adult-onset LCH were found to have a high risk of developing miscellaneous malignant cancers (SIR 11.43), which primarily included myelodysplastic syndrome. Adults were also at a high risk of developing carcinoma in-situ of vulva at 2-11 months [SIR 62.72] and B-ALL at 60-119 months [SIR 66.29] after LCH diagnosis. Additionally, 5% and 1% of the patients developed prior or concomitant malignancies with LCH, respectively. The 5 yr overall survival (OS) was 96.6% for pediatric and 88.5% for adult LCH cohorts. Most common cause of death was infections in pediatric and SPMs in adult LCH. Our study highlights that despite advances in treatments, people with LCH have an increased mortality risk from non-LCH causes when compared with the general population, including a high risk of SPMs.

Long-term Outcomes of Adult Pulmonary Langerhans Cell Histiocytosis: A Prospective Cohort

BACKGROUND

The long-term outcomes of adult pulmonary Langerhans cell histiocytosis (PLCH), particularly survival, are largely unknown. Two earlier retrospective studies reported a high rate of mortality, which contrasts with our clinical experience.

METHODS

To address this issue, all newly diagnosed PLCH patients referred to the French national reference centre for histiocytoses between 2004 and 2018 were eligible for inclusion. The primary outcome was survival, which was defined as the time from inclusion to lung transplantation or death from any cause. Secondary outcomes included the cumulative incidences of chronic respiratory failure (CRF), pulmonary hypertension (PH), malignant diseases, and extra-pulmonary involvement in initially isolated PLCH. Survival was estimated using the Kaplan-Meier method.

RESULTS

Two hundred six patients (mean age: 39±13 years, 60% females, 95% current smokers) were prospectively followed for a median duration of 5.1 years (interquartile range [IQR], 3.2 to 7.6). Twelve (6%) patients died. The estimated rate of survival at 10 years was 93% (95% confidence interval [CI], 89-97). The cumulative incidences of CRF and/or PH were less than 5% at both 5 and 10 years, and 58% of these patients died. Twenty-seven malignancies were observed in 23 patients. The estimated standardized incidence ratio of lung carcinoma was 17.0 (95% CI, 7.45-38.7) compared to an age- and sex-matched French population. Eight (5.1%) of the 157 patients with isolated PLCH developed extra-pulmonary involvement.

CONCLUSIONS

The long-term prognosis of PLCH is significantly more favourable than was previously reported. Patients must be closely monitored after diagnosis to detect severe complications early.

Langerhans Cell Histiocytosis Associated With Underlying Hematolymphoid Disorders in Adults: Report of 2 Cases and Review of the Literature

Langerhans cell histiocytosis (LCH) is an uncommon disorder characterized by proliferation of abnormal LCs usually affecting children and adolescents. LCH in adults first presenting in the skin is rare. Although LCH and even LCH with a second malignancy may be more common in children, cutaneous LCH with a second hematologic malignancy has been more commonly identified in adults. The authors report 2 new cases of LCH in adult patients with underlying myelodysplasia and follicular lymphoma. The specimens were examined by routine microscopy and immunohistochemical stains for S100 protein and CD1a. Patients were elderly men with established diagnoses of follicular lymphoma and myelodysplasia, presented with follicular lesions and erythematous plaques involving intertriginous areas. Histologic examination revealed collections of mononuclear cells in upper dermis, which demonstrated strong positivity for S100 and CD1a, confirming their identity as LCs. BRAF analysis returned negative for detection of BRAF V600E mutation in both patients. The authors have recently encountered 2 cases of adult patients with skin-limited LCH predated by other lymphoproliferative disorders. The association between LCH and hematopoietic disorders may be explained by a common bone marrow precursor that is differentiating along different cell lines. Cutaneous LCH may be associated with underlying lymphoproliferative disorders and should be considered in the differential diagnosis of cutaneous eruptions in patients with hematopoietic disorders. Clinical follow-up evaluation of patients diagnosed with LCH for peripheral blood abnormalities and lymphadenopathy or "B symptoms" may be prudent in patients not already carrying a diagnosis of an underlying hematologic disorder.

Occult Langerhans Cell Histiocytosis in Clear Cell Renal Cell Carcinoma

Langerhans cell histiocytosis is a rare disease that is characterized by a localized or systemic proliferation of Langerhans dendritic cells and a wide spectrum of clinical presentations. We experienced an unusual case of occult Langerhans cell histiocytosis associated with clear cell renal cell carcinoma. A 62-year-old man underwent a partial nephrectomy for left renal mass. Histologic examination showed nests of clear cells with surrounding thin-walled vessel that were suggestive of clear cell renal cell carcinoma. A well-defined nodule composed of atypical mononuclear cells and plentiful eosinophils presented within clear cell renal cell carcinoma. The mononuclear cells were Langerhans cell histiocytes with S-100 and CD1a immunoreactivity. On follow-up comprehensive physical, laboratory, and radiologic examination, there were no other lesions of Langerhans cell histiocytosis.

Clonal reticulohistiocytosis of the skin and bone marrow associated with systemic mastocytosis and acute myeloid leukaemia

AIMS

The aims of this study were to define whether diffuse cutaneous reticulohistiocytosis could be underpinned by somatic genetic alterations and represent a precursor of more aggressive forms of disease.

METHODS AND RESULTS

A 59-year-old man with diffuse cutaneous reticulohistiocytosis experienced bone marrow localization of the disease, with associated systemic mastocytosis and acute myeloid leukaemia. Cytogenetic analyses of the bone marrow aspirate revealed the presence of a derivative chromosome giving rise to a partial trisomy of chromosome 1q and a partial monosomy of chromosome 9q. Therefore, we characterized the cutaneous lesions before and after chemotherapy by using an integrative approach combining histopathology, electron microscopy, and fluorescence in-situ hybridization. Histologically, the skin lesions belonged to the spectrum of diffuse cutaneous reticulohistiocytoses, as confirmed by immunohistochemistry and ultrastructural analyses. Fluorescence in-situ hybridization in the skin nodules confirmed the presence of the genetic alterations previously detected in the bone marrow.

CONCLUSIONS

Here, we provide circumstantial evidence to suggest that at least a subset of cutaneous reticulohistiocytoses harbour clonal molecular alterations. Furthermore, we confirm that these lesions have the potential to arise in the setting of concurrent haematological disorders. In this hypothesis-generating study, two possible tumorigenesis models are proposed.

Cutaneous Langerhans cell histiocytosis in elderly with chronic myelomonocytic leukemia

Langerhans cell histiocytosis (LCH) is a rare histiocytic neoplasm characterized by clonal proliferation of Langerhans cells in multi-organ systems including skin, bone, pituitary gland, liver and spleen. Skin-limited involvement of LCH usually indicates an indolent clinical course; however, in rare cases, LCH is accompanied by other myeloproliferative disorders, which may determine the prognosis. An 82-year old Japanese man presented with numerous asymptomatic facial papules clinically simulating rhinophyma. Although findings of histopathology and general examination including bone marrow biopsy led to the diagnosis of cutaneous LCH, he died from chronic myelomonocytic leukemia, which emerged 10 months after the initial diagnosis of LCH. The previously reported cases of LCH concomitant with other hematological disorders are also summarized and described compared with the present case.

Langerhans Cell Sarcoma in a Chronic Myelogenous Leukemia Patient Undergoing Imatinib Mesylate Therapy

Langerhans cell sarcoma (LCS) is a rare malignancy requiring differential diagnosis from other high-grade nonhematologic and hematologic tumors. The pathogenesis of LCS remains unknown. Notably, LCS and its benign counterpart, Langerhans cell histiocytosis (LCH), are frequently associated with other malignancies. To the best of our knowledge, we describe the first case of LCS in a chronic myelogenous leukemia (CML) patient undergoing imatinib mesylate therapy. We performed molecular cytogenetic analyses for investigating the association between LCS and CML. In our case, molecular cytogenetic analysis did not reveal BCR-ABL1 fusion and BRAF V600E mutation, suggesting that LCS may be coincident in this patient. However, recurrent BRAF V600E mutation has been found in LCH. Published reports have revealed the clonal relationship between LCH/LCS and other hematologic malignancies, especially lymphoid neoplasms. However, there are only 2 reports demonstrating the clonal relationship between LCH and myeloid neoplasms. The association of LCH/LCS with myeloid neoplasms and the role of BRAF V600E mutation in LCS are discussed.

Langerhans cell histiocytosis first presenting in the skin in adults: frequent association with a second haematological malignancy

BACKGROUND

Langerhans cell histiocytosis (LCH) in adults first presenting in the skin is rare. Guidelines for staging, treatment and follow-up are lacking.

OBJECTIVES

To better define staging procedures, treatment results and clinical course in adult patients with LCH first presenting in the skin.

METHODS

Eighteen adult patients with LCH first presenting in the skin were collected from five centres collaborating in the Dutch Cutaneous Lymphoma Group. Clinical records and (skin) biopsy specimens were reviewed and follow-up data were obtained. A literature search on adult patients with LCH presenting in the skin was performed.

RESULTS

Staging procedures showed extracutaneous disease in three of 16 patients who were adequately staged. One patient had a histologically confirmed lytic LCH bone lesion, while two patients had a myelodysplastic syndrome. During follow-up two of 18 patients developed extracutaneous localizations of LCH. Five patients developed a second haematological malignancy, including (myelo)monocytic leukaemia (two cases), histiocytic sarcoma (one case), diffuse large B-cell lymphoma (one case) and peripheral T-cell lymphoma (one case). Review of the literature revealed six other adult patients with a second haematological malignancy preceding or following a diagnosis of LCH.

CONCLUSIONS

The results of the present study suggest an increased risk of a second haematological malignancy in adult patients with LCH presenting in the skin. Extensive staging at presentation and long-term follow-up are therefore warranted in such patients.

Specific skin lesions in chronic myelomonocytic leukemia: a spectrum of myelomonocytic and dendritic cell proliferations: a study of 42 cases

Chronic myelomonocytic leukemia (CMML) is a rare clonal hematopoietic disorder that can also involve the skin. The histopathology of these skin lesions is not clearly defined, and few data are available in the literature. To better understand tumoral skin involvements in CMML we carried out an extensive, retrospective clinicopathologic study of 42 cases selected from the database of the French Study Group of Cutaneous Lymphomas. On the basis of clinical data, morphology, and phenotype we identified 4 clinicopathologic profiles representing 4 distinct groups. The first group comprised myelomonocytic cell tumors (n=18), exhibiting a proliferation of granulocytic or monocytic blast cells, which were CD68 and/or MPO positive but negative for dendritic cell markers. The second group comprised mature plasmacytoid dendritic cell tumors (n=16), denoted by a proliferation of mature plasmacytoid dendritic cells, which were CD123, TCL1, and CD303 positive but CD56, CD1a, and S100 negative. The third group comprised blastic plasmacytoid dendritic cell tumors (n=4), characterized by a proliferation of monomorphous medium-sized blast cells, which were CD4, CD56, CD123, TCL1 positive but CD1a and S100 negative. The fourth group consisted of a putatively novel category of tumor that we named blastic indeterminate dendritic cell tumors (n=4), distinguished by a proliferation of large blast cells that not only exhibited monocytic markers but also the dendritic markers CD1a and S100. These 4 groups showed distinctive outcomes. Finally, we showed, by fluorescence in situ hybridization analysis, a clonal link between bone marrow disease and skin lesions in 4 patients. Herein, we have described a novel scheme for pathologists and physicians to handle specific lesions in CMML, which correspond to a spectrum of myelomonocytic and dendritic cell proliferations with different outcomes. A minimal panel of immunohistochemical markers including CD68, CD1a, S100, Langerin, and CD123 is necessary to make the correct classification in this spectrum of cutaneous CMML tumors, in which dendritic cell lineage plays an important role.

Langerhans cell histiocytosis mimicking malignant melanoma: a diagnostic pitfall

Langerhans cell histiocytosis (LCH), especially with an involvement limited to the skin, is a rare entity in adults. In formulating a differential diagnosis of a solitary skin lesion, LCH is rarely considered. Morphologically, cells seen in LCH can mimic those seen in a melanocytic tumor; moreover, they both show S-100 protein reactivity with immunoperoxidase staining. A 63-year-old male presented to a dermatology clinic with a solitary hyperpigmented macule on his right calf. A biopsy specimen showed epithelioid cells within the dermis, singly and in small groups, surrounded and infiltrated by collections of histiocytes and lymphocytes. These cells were diffusely positive for S-100 and negative for Melan-A. A diagnosis of malignant melanoma, spitzoid variant, was rendered, and the patient was sent to our melanoma center for surgical treatment. On histologic examination, some of the lesional cells had reniform, vesicular nuclei with central grooves. Additional immunoperoxidase staining showed strong, diffuse positivity for CD1a, supporting the diagnosis of LCH. LCH is morphologically similar to and can be misdiagnosed as malignant melanoma. It is important to be aware of this pitfall and utilize immunohistochemical and ultrastructural analysis to achieve correct diagnosis.

The solitary lymphomatous papule, nodule, or tumor

BACKGROUND

Lymphoma and reactive lymphoid infiltrates presenting as solitary lesion pose a diagnostic and prognostic dilemma for the clinician.

OBJECTIVE

We sought to review prognosis and treatment of suggestive solitary lymphoma lesions.

METHODS

A retrospective chart review was conducted in 27 patients who presented with a single solitary lesion suggestive of lymphoma at a cancer center.

RESULTS

Eighteen of 27 patients' (66.7%) lesions were diagnosed as lymphoma by histology and the remainder was classified as reactive lymphoid infiltrates. Only one patient's lymphoma was systemic at presentation and one progressed later. In all, 23 patients (85.2%) subsequently experienced prolonged, complete remissions. The treatments used varied from none or conservative to chemotherapy, with the more aggressive treatments directed especially against lymphomas or recurrent diseases.

LIMITATIONS

This study is limited by the number of patients and follow-up duration (average 36.8 months, range 3-133 months).

CONCLUSION

Patients presenting with a solitary lesion suggestive of lymphoma and negative staging work-up results generally have a good prognosis. Excellent prognosis is usually expected for benign lesions.