Langerhans cell sarcoma with BRAF-V600E mutation and hemophagocytosis: An autopsy report.

Langerhans cell sarcoma (LCS) is a rare high-grade neoplasm of langerhans cell phenotype having unambiguous malignant cytological features. We report such a rare case in a 20-year-old man who presented with dyspnea and high-grade fever. On evaluation, he had generalized lymphadenopathy, hepatosplenomegaly, and a large anterior mediastinal mass. Fine needle aspiration from the mediastinal mass and bone marrow aspirate showed numerous atypical cells, many of which showed grooved nuclei. In addition, the bone marrow showed prominent hemophagocytosis. The patient had a stormy hospital stay and succumbed to the illness. The autopsy revealed a rare multisystem involvement by LCS involving the lymph nodes, liver, spleen, lungs, and intestine, which harbored a BRAFV600E mutation and was associated with hemophagocytosis.

[Langerhans cell sarcoma: a clinicopathologic analysis of four cases].

Objective: To investigate the clinicopathological features, differential diagnosis, and genetic alteration of Langerhans cell sarcoma (LCS). Methods: Four cases of LCS were collected from Fujian Provincial Hospital and Fuzhou General Hospital of Nanjing Military Command of PLA from July 2013 to January 2017. Clinicopathological features and immunophenotype were retrospectively reviewed in four LCS cases combined with genetic mutation analysis of BRAF and ALK. Results: Four cases included 2 women and 2 men with ages from 42 to 79 years (median=59.3 years). The size of the tumors ranged from 2.5-7.8 cm. Histologically, at the low power field, the tumors consisted of highly cellular proliferation in fascicules, whirlpool and diffuse sheets arrangement. The tumor cells were kidney-or horseshoe-shaped to round epithelioid cells or enlarged spindle cells. The neoplastic cells showed cytological atypia, hyperchromatic nuclei with prominent 1 to 2 nucleoli. Multinucleated giant cells were also found. Mitotic activity was approximately (50-70) mitoses/10 HPF. Immunohistochemically, the tumor cells were positive for S-100 protein (4/4), SOX10(3/4), Langerin/CD207(4/4), CD1a(3/4), CD68(3/4), CD163(3/4), and INI-1(4/4). Ki-67 index was 30%-80%. Gene mutation analysis showed that one case had BRAF V600E mutation but none had ALK gene alteration. Conclusions: LCS is a rare tumor with highly malignant potential and distinct morphologic features.The primary treatment for LCS is completely surgical excision and chemotherapy. The prognosis is generally poor.

CDKN2A/B Deletion and Double-hit Mutations of the MAPK Pathway Underlie the Aggressive Behavior of Langerhans Cell Tumors.

Langerhans cell histiocytosis (LCH) has a mostly favorable outcome, whereas Langerhans cell sarcoma (LCS) is an aggressive tumor. It is still unclear whether any specific molecular alterations could underlie the aggressive behavior of Langerhans cell proliferations. We used targeted next-generation sequencing and array-comparative genomic hybridization to profile 22 LCH samples from different patients together with 3 LCS samples corresponding to different relapses from the same patient. The third LCS relapse was a composite tumor including both B-cell chronic lymphocytic leukemia and LCS components. The 22 LCH samples were mostly of bone origin and showed classic histophenotypical features. Array-comparative genomic hybridization showed in all 3 LCS samples a similar homozygous somatic loss affecting the CDKN2A/B locus, whereas the 17 informative LCH samples did not show any detectable abnormality. In the 3 LCS samples, targeted next-generation sequencing of 495 cancer genes detected common mutations in KMT2D/MLL2 and in both MAP2K1 and NRAS genes, whereas BRAF was not mutated. A NOTCH1 mutation was acquired in 2 LCS samples. The composite LCS/B-cell chronic lymphocytic leukemia tumor showed the same genetic profile in its 2 components. LCH samples showed mutually exclusive mutations of BRAF (8/20) and MAP2K1 (4/19), but no mutation of KMT2D, NRAS nor NOTCH1. These results suggest that CDKN2A/B deletion and/or simultaneous mutations of MAP2K1 and NRAS may underlie the aggressive behavior of Langerhans cell tumors, and thus could be useful for the diagnosis of malignancy in histiocytic neoplasms. The MAPK pathway "double hit" profile provides a basis for targeted therapy in LCS patients.

A Case of Pulmonary Langerhans Cell Sarcoma Simultaneously Diagnosed with Cutaneous Langerhans Cell Histiocytosis Studied by Whole-Exome Sequencing.

Langerhans cell histiocytosis (LCH) and Langerhans cell sarcoma (LCS) are clonal proliferations of Langerhans-type cells. Unlike in LCH, the pathophysiology and clinical course of LCS are unclear due to its rarity. Here, we report the case of a 73-year-old male patient who was diagnosed with cutaneous LCH and pulmonary LCS at the same time. Pathological review of these 2 tumors revealed similar immunohistochemical findings. However, the tumor cells in LCS had more aggressive cytological features than those in LCH. Results of BRAF mutation analysis using real-time PCR were negative for both tumors. In whole-exome sequencing (WES), stop-gain mutations in TP53 gene were discovered only in LCS cells. The mechanism of development of LCS from various progenitor cells is currently unclear. According to the results of the WES study, changes in TP53 gene might have contributed to the malignant features of LCS.

Cytological findings of langerhans cell sarcoma in a case of quintuple cancer.

Langerhans cell sarcoma (LCS) and quintuple cancers are extremely rare. In this report, a case of quintuple cancers including LCS was described. An 80-year-old man had squamous cell carcinoma of the nasal skin, colon and rectum adenocarcinomas, and T-cell/histiocyte-rich large B-cell lymphoma. As swelling of multiple submental lymph nodes was observed, fine-needle aspiration was carried out. Many large cells with high-grade nuclear atypia and abundant cytoplasm were observed. Lymphocytes and eosinophils were observed in the background. Although a malignant tumor was suspected, a definite diagnosis could not be made. In a biopsy sample, the tumor cells were positive for vimentin, CD68, S-100, CD1a, and CD163 and negative for epithelial, lymphocyte, and melanoma markers in immunohistochemistry. A diagnosis of LCS was made from the immunohistochemical findings and high mitotic rate with atypical forms. The patient died about 2 months after the first medical examination. Metastasis of LCS was confirmed in many organs by autopsy. LCS has a poor prognosis. In cases with the above-described cytological findings, LCS should be added to the list of differential diagnosis. The cytological findings presented here may be useful for determining appropriate clinical management such as staging of the disease and follow-up of the neoplasm. Diagn. Cytopathol. 2017;45:441-445. © 2017 The Authors Diagnostic Cytopathology Published by Wiley Periodicals, Inc.

High frequency of clonal IG and T-cell receptor gene rearrangements in histiocytic and dendritic cell neoplasms.

The 2008 World Health Organization (WHO) diagnostic criteria of histiocytic and dendritic cell neoplasms from hematopoietic and lymphoid tissues no longer required the absence of clonal B-cell/T-cell receptor gene rearrangements. It is true that the clonal B-cell/T-cell receptor gene rearrangements have been identified in rare cases of histiocytic and dendritic cell neoplasms, such as those with or following lymphoma/leukemia or in some sporadic histiocytic/dendritic cell sarcomas, but the clonal features of such group of tumor are still not clear. Here we investigated the clonal status of 33 samples including Langerhans cell histiocytosis (LCH), Langerhans cell sarcoma (LCS), follicular dendritic cell sarcoma (FDCS), interdigitating dendritic cell sarcoma (IDCS) and histiocytic sarcoma (HS). Among them, twenty-eight cases were sporadic without current or past lymphoma/leukemia. Three cases were found with a past history of T-cell lymphoma, one case was followed by extraosseous plasmacytoma, and one case was found with diffuse large B-cell lymphoma (DLBCL). Our results showed that there was a high frequency of clonal IG and T-cell receptor gene rearrangements in these cases. Notably, 4 cases of LCH and 2 cases of FDCS showed both B and T cell receptor gene rearrangements concurrently. One case of FDCS synchronous with DLBCL showed identical clonal IGH in both tumor populations and clonal TCRß in FDCS alone. No matter if the presence of clonal receptor gene rearrangements was associated with the tumor origin or tumorigenesis, it might serve as a novel tumor marker for developing target therapy.

Langerhans cell sarcoma with lineage infidelity/plasticity: a diagnostic challenge and insight into the pathobiology of the disease.

Langerhans cell sarcoma is a very rare and aggressive tumor of Langerhans cell lineage, for which aberrant expression of T-cell-related antigens has not yet been reported in a primary skin tumor. The authors describe the first known case of a primary cutaneous Langerhans cell sarcoma with lineage infidelity and use comparative genomic hybridization to investigate the genetic composition of the tumor and detect DNA copy number alterations throughout its entire genome. The case involves a 62-year-old woman who presented with an irregular nodule on the forehead surrounded by smaller lesions in its vicinity. The clinical impression was melanoma with satellitosis. The biopsy specimen showed an epidermotropic tumor with moderate-to-marked cellular pleomorphism and significantly increased mitotic rate but no necrosis. The immunoprofile of the lesion was remarkable, as next to common Langerhans cell markers: Langerin, CD1a, S100, and CD4; it also exhibited an aberrant T-cell phenotype with the expression of CD2, CD3, and CD43. In addition, fascin and CD30 were also expressed, further exaggerating potential diagnostic pitfalls. Langerhans cell lineage was confirmed by the demonstration of characteristic Birbeck granules on electron microscopy. Whole genome analysis for copy number changes and loss of heterozygosity showed a complex karyotype with variable hyperdiploidy and numerous allelic imbalances. Significant findings included a homozygous deletion at 9p21 involving the CDKN2A and loss of heterozygosity at 17p involving TP53 gene, coupled with a TP53 missense mutation. Despite reexcision and multiagent systemic chemotherapy, the patient died of metastasis 2 years after diagnosis. This case is an outstanding example of lineage infidelity in a hematologic malignancy and the utilization of comparative genomic hybridization in characterizing its genetic abnormalities.

Langerhans cell sarcoma following marginal zone lymphoma: expanding the knowledge on mature B cell plasticity.

The concept of unidirectional differentiation of the haematopoietic stem cell has been challenged after recent findings that human B cell progenitors and even mature B cells can be reprogrammed into histiocytic/dendritic cells by altering expression of lineage-associated transcription factors. The conversion of mature B cell lymphomas to Langerhans cell neoplasms is not well documented. Three previous reports have described clonally related follicular lymphoma and Langerhans cell tumours, whereas no case has been published of clonally related marginal zone lymphoma and Langerhans cell sarcoma. We describe the case of a 77-year-old patient who developed a Langerhans cell sarcoma and 6 years later a nodal marginal zone lymphoma. Mutation status examination showed 100 % gene identity to the germline sequence, suggesting direct trans-differentiation or dedifferentiation of the nodal marginal zone lymphoma to the Langerhans cell sarcoma rather than a common progenitor. We found inactivation of paired box 5 (PAX-5) in the lymphoma cells by methylation, along with duplication of part of the long arm of chromosomes 16 and 17 in the sarcoma cells. The absence of PAX-5 could have triggered B cells to differentiate into macrophages and dendritic cells. On the other hand, chromosomal imbalances might have activated genes involved in myeloid lineage maturation, transcription activation and oncogenesis. We hypothesize that this occurred because of previous therapies for nodal marginal zone lymphoma. Better understanding of this phenomenon may help in unravelling the molecular interplay between transcription factors during haematopoietic lineage commitment and may expand the spectrum of clonally related mature B cell neoplasms and Langerhans cell tumours.

Langerhans cell sarcoma: case report and review of world literature.

Langerhans cell sarcoma is a rare malignancy with only 1 pediatric case (less than 15 y of age) reported. Here, we report the second case of Langerhans cell sarcoma in a child who presented with cord compression. This patient was treated with extensive surgical resection, postoperative chemotherapy, and involved-field radiation therapy. She completed therapy and remains in remission for 27 months. A review and analysis of all 53 cases published in the world literature is provided to help guide physicians treating this disease. Recently discovered genetic mutation involving BRAF is also discussed.

Clonally related follicular lymphomas and Langerhans cell neoplasms: expanding the spectrum of transdifferentiation.

The traditional model of hematopoiesis is based on unidirectional maturation of hematopoietic precursors into lineage-committed cells. However, recent studies indicate that mature B lymphocytes may demonstrate significant lineage plasticity. We and others have reported transdifferentiation of follicular lymphomas (FLs) into clonally related histiocytic/dendritic cell neoplasms. Here, we describe 2 patients with FL who developed clonally related Langerhans cell neoplasms. The first was a 52-year-old man diagnosed with FL, grade 1. He received immunochemotherapy and had stable disease for 8 years. He then developed increasing lymphadenopathy, and lymph node biopsy showed Langerhans cell sarcoma with no evidence of FL. The second patient was a 77-year-old woman who presented with lymphadenopathy, an abdominal mass, and pulmonary nodules. Lymph node biopsy showed both Langerhans cell histiocytosis and minimal involvement by FL, grade 1. In each case, a combination of immunoglobulin gene rearrangement and fluorescence in situ hybridization studies provided evidence to support a clonal relationship between the FL and Langerhans cell neoplasm. These cases provide striking examples of neoplastic transdifferentiation and expand the spectrum of lesions clonally identical to otherwise typical FL. Awareness of this phenomenon may aid in diagnosis when histologically dissimilar tumors arise synchronously or metachronously in patients with lymphoma.

Langerhans cell sarcoma with an aberrant cytoplasmic CD3 expression.

Langerhans cell sarcoma is a rare and aggressive high grade hematopoietic neoplasm with a dismal prognosis. It has a unique morphological and immunotypic profile with a CD1a/ langerin/S100 + phenotype. T cell lineage markers except for CD4 in Langerhans cell sarcoma have not been documented previously. We report a case of 86 year-old male of Caucasian descent who presented with an enlarging right neck mass over 2 months with an underlying unknown cause of anemia. Computed tomography scan of the neck, chest and abdomen revealed generalized lymphadenopathy and mild splenomegaly suspicious for lymphoma. Diagnostic core biopsy performed on right neck mass revealed a possible T cell lymphoma with expression of T cell lineage specific marker CD3 but conclusive diagnosis could not be made due to insufficient core biopsy sample. Further excisional biopsy performed on a left inguinal node showed a hematopoietic neoplasm with features of Langerhans cell sarcoma with a focal cytoplasmic CD3 expression in 30-40% of the tumor cells. PCR for T cell receptor (TCR) gene rearrangement failed to demonstrate a clonal gene rearrangement in the tumor cells arguing against a T cell lineage transdifferentiation, suggesting an aberrant CD3 expression. To the best of our knowledge, this case represents the first report of Langerhans cell sarcoma with an aberrant cytoplasmic CD3 expression. VIRTUAL SLIDES: http://www.diagnosticpathology.diagnomx.eu/vs/2065486371761991.

Langerhans cell sarcoma in a patient with hairy cell leukemia: common clonal origin indicated by identical immunoglobulin gene rearrangements.

Histiocytic/dendritic cell sarcomas are rare tumors, a few of which have been reported in association with B-cell lymphoma/leukemia. Isolated reports have documented identical immunoglobulin gene rearrangements suggesting a common clonal origin for both the sarcoma and the B-cell neoplasm from individual patients. We report a case of a 75-year-old male with hairy cell leukemia who subsequently developed Langerhans cell sarcoma 1 year after his primary diagnosis of leukemia. The bone marrow biopsy containing hairy cell leukemia and skin biopsies of Langerhans cell sarcoma were evaluated by routine histology, immunohistochemistry, flow cytometric immunophenotyping and PCR-based gene rearrangement studies of the immunoglobulin heavy chain and kappa genes. The hairy cell leukemia showed characteristic morphologic, immunohistochemical and flow cytometric features. The Langerhans cell sarcoma showed pleomorphic cytology, a high mitotic rate and characteristic immunohistochemical staining for Langerin, S100 and CD1a. There was no evidence of B-cell differentiation or a background B-cell infiltrate based on the absence of immunoreactivity with antibodies to multiple B-cell markers. Identical immunoglobulin gene rearrangements were identified in both the hairy cell leukemia and Langerhans cell sarcoma specimens. Despite the phenotypic dissimilarity of the two neoplasms, identical immunoglobulin gene rearrangements indicate a common origin.

Clonally related histiocytic/dendritic cell sarcoma and chronic lymphocytic leukemia/small lymphocytic lymphoma: a study of seven cases.

Histiocytic and interdigitating dendritic cell sarcomas are rare tumors originating from bone marrow-derived myeloid stem cells. Recent studies have shown evidence of cross-lineage transdifferentiation of B cells in follicular lymphoma to histiocytic and dendritic cell sarcomas. In this study, we report the morphologic, molecular and cytogenetic analysis of seven cases of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) associated with histiocytic and dendritic cell sarcomas. All seven patients were elderly males (median age 71 years). The B-cell neoplasms preceded the development of the histiocytic and dendritic cell sarcomas in six of seven patients, and one patient had both tumors diagnosed at the same time. The tumors included four interdigitating dendritic cell sarcomas: one Langerhans cell sarcoma, one histiocytic sarcoma and one immature neoplasm with evidence of histiocytic origin. Laser-capture microdissection and PCR analysis showed identical clonal immunoglobulin gene rearrangements in the two phenotypically distinct components in all cases. There was a preferential usage of IGHV4-39 by the V-D-J gene rearrangement. By fluorescence in situ hybridization (FISH) analysis, two cases showed deletion 17p in both components, whereas four cases had normal cytogenetic findings by FISH in the CLL/SLL cells, but acquired cytogenetic abnormalities in the corresponding histiocytic and dendritic tumors. Chromosome 17p abnormalities were the most common cytogenetic abnormality detected in the sarcomas, seen in five of six cases studied. Compared with the CLL/SLL cells, the histiocytic/dendritic cells were largely negative for PAX5, but showed strong expression of PU.1 and variable and weak expression of CEBPß. Our study provides evidence for transdifferentiation of CLL/SLL B cells to tumors of dendritic and less often histiocytic lineage, and suggests that secondary genetic events may play a role in this phenomenon.