The epidemiological and clinical characteristics of Langerhans cell sarcoma in the United States: A population study based on SEER data from 2000 to 2019.

Langerhans cell sarcoma (LCS) is a rare aggressive malignancy with a poor prognosis. Our knowledge about this condition is limited and mainly based on case reports, making it challenging to understand its epidemiology, clinical features, and patient outcomes. We conducted a retrospective study of LCS patients diagnosed between 2000 and 2019 using the Surveillance, Epidemiology, and End Results (SEER) database. The data were stratified based on age, race, stage, clinical pattern, and treatment method. Our study found that 57 LCS cases were reported in SEER registries between 2000 and 2019. Among these cases, most patients (50.9%) were over 60 years old and White (71.9%) with almost equal males to females ratio. About 45.6% of cases were localized while 47.4% were at distant stages. Of the patients, 50.9% underwent surgery, 45.6% received chemotherapy, and only 21.1% received radiotherapy. The overall survival rate for patients diagnosed with LCS in the United States is generally low with a 1-year overall rate of 63.8%. Certain factors can negatively impact prognosis, such as advanced stages of the disease, secondary tumors, or more than 1 tumor per patient. LCS is a rare disease with poor survival rates. Future research should incorporate global data for further statistically significant results. Moreover, investigating the molecular, genetic, and pathophysiological backgrounds of these tumors is crucial for developing targeted management strategies and improving prognosis.

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.

Unusual presentation of Langerhans cell sarcoma as bilateral submandibular gland swelling - A rare case report.

Langerhans cell sarcoma (LCS) is a rare malignant tumor of Langerhans cells and uncommonly involves head and neck regions. Unlike Langerhans cell histiocytosis (LCH), it has an aggressive clinical course with malignant cytological features. Till now, a handful of cases have been reported and the common anatomical sites involved are skin, lymph node, and bone in loco - regional cases and lymph node, lung, liver, spleen, and bone in disseminated disease. Due to its rarity, standard protocols of treatment for these patients are not yet well established. Herein, we report such a case in a 25-year-old male presenting with a bilateral submandibular swelling, which was diagnosed as LCH on Fine Needle Aspiration Cytology (FNAC) and later confirmed to be a case of LCS in histopathological examination and immunohistochemistry. The authors are aware of only a single similar case being reported in the English literature.

From the archives of MD Anderson Cancer Center: A case of concurrent follicular lymphoma and Langerhans cell sarcoma with a review of the literature.

Transdifferentiation of follicular lymphoma to a Langerhans cell neoplasm is rarely reported and not well understood. Here we present a case, review the literature and discuss some of the biological underpinnings of lineage switch of B cells to histiocytes/Langerhans cells. A 31-year-old woman had follicular lymphoma (FL) and Langerhans cell sarcoma (LCS) co-localized above and below diaphragm. The FL was low-grade, had typical morphologic features, and was positive for CD10, BCL-2, and BCL-6. The LCS was cytologically atypical with necrosis and a high mitotic rate, and the immunophenotype supported Langerhans cell lineage positive for CD1a, CD207/langerin, and S-100 protein. Both tumors carried IGH-BCL2 and the LCS cells had immunophenotypic evidence of a residual B cell program, supporting the notion that these neoplasms are clonally related. The case reported is unusual because the patient was young and both diseases presented simultaneously, before any therapy. In addition, immunohistochemical analysis showed that the LCS was negative for BRAF V600E and phospho-ERK, suggesting that the LCS belongs to the known subset of Langerhans cell tumors lacking BRAF V600E and MAP2K1 mutations. Concurrent occurrence of FL and Langerhans cell neoplasm is an unusual phenomenon, with 10 cases reported previously: 4 Langerhans cell histiocytosis and 6 Langerhans cell sarcoma, including this case.

Histiocytic and dendritic cell neoplasms: Reappraisal of a Japanese series based on t(14;18) and neoplastic PD-L1 expression.

Histiocytic and dendritic cell (H/DC) neoplasms are heterogeneous, originating from myeloid- or stromal-derived cells. Multiple reports describe the cross-lineage transdifferentiation of neoplastic B cells into H/DC neoplasms. Most such cases are from Western countries, and rarely from Japan or East Asia. Here we report 17 cases of H/DC neoplasms in Japanese patients, with analysis of t(14;18) by fluorescence in situ hybridization, and of neoplastic programmed death-ligand 1 (PD-L1) expression by immunostaining (clones SP142, E1J2J, and 28-8). These 17 cases were diagnosed according to the 2017 World Health Organization (WHO) classification, and included two histiocytic sarcomas (HS), two interdigitating cell (IDC) sarcomas, one Langerhans cell sarcoma, two dendritic cell sarcomas, and 10 follicular dendritic cell (FDC) sarcomas. No case had any past history of follicular lymphoma (FL). Two cases of HS and one IDC sarcoma, all of which were myeloid-driven, were found to exhibit t(14;18). In the latter case, at 30 months after IDC sarcoma diagnosis, FL development was detected. Three (30%) FDC sarcoma cases exhibited neoplastic PD-L1 expression with all the three PD-L1 antibody clones. This is the first report of t(14;18) and neoplastic PD-L1 expression on H/DC neoplasms among Japanese patients, each of which appeared to be associated with HS and FDC sarcoma, respectively.

A case of Langerhans cell sarcoma on the scalp: Whole-exome sequencing reveals a role of ultraviolet in the pathogenesis.

Langerhans cell sarcoma (LCS) is a high-grade neoplasm with overtly malignant cytological features and a Langerhans cell phenotype. The underlying genetic features are poorly understood, and only a few alterations, such as those of the MARK pathway-related genes, CDKN2A and TP53 have been reported. Here we present a 70-year-old male with LCS on the scalp and pulmonary metastasis. The multinodular tumor, 3.0 cm in diameter, consisted of diffusely proliferated pleomorphic cells with numerous mitoses (53/10 HPFs). Immunohistochemically, the tumor cells were positive for CD1a, Langerin and PD-L1, and the Ki-67 labeling index was 50%. These pathological features were consistent with LCS, and were also observed in the metastatic tumor. Whole-exome sequencing revealed that both the primary and metastatic tumors harbored a large number of mutations (>20 mutations/megabase), with deletion of CDKN2A and TP53 mutation, and highlighted that the mutational signature was predominantly characteristic of ultraviolet (UV) exposure (W = 0.828). Our results suggest, for the first time, that DNA damage by UV could accumulate in Langerhans cells and play a role in the pathogenesis of LCS. The high mutational burden and PD-L1 expression in the tumor would provide a rationale for the use of immune checkpoint inhibitors for treatment of unresectable LCS.

Concurrent cutaneous localization of Langerhans cell sarcoma and chronic lymphocytic leukemia/small lymphocytic lymphoma in a patient with a history of chronic lymphocytic leukemia/small lymphocytic lymphoma.

The phenomenon of histiocytic/dendritic cell sarcomas arising through transformation of a pre-existed lymphoproliferative disease is called transdifferentiation. Langerhans cell sarcoma transdifferentiating from chronic lymphocytic leukemia/small lymphocytic lymphoma is extremely rare and all the reported cases were localized in lymph nodes. We present a case of concurrent cutaneous localization of Langerhans cell sarcoma and chronic lymphocytic leukemia/small lymphocytic lymphoma, in which the chronic lymphocytic leukemia/small lymphocytic lymphoma preceded the development of the Langerhans cell sarcoma. A cutaneous lesion from a 63-year-old patient with a history of chronic lymphocytic leukemia/small lymphocytic lymphoma was biopsied. The histologic examination revealed a mixture of two cell populations infiltrating diffusely the dermis. The first was composed of small lymphoid cells with somewhat monotonous appearance and mild nuclear atypia positive for PAX5, CD79a, CD20, CD23, CD5, and LEF1. The second was composed of large cells with abundant cytoplasm and pleomorphic nuclei. These cells were positive for CD1a, CD207, and S100 protein and exhibited a high mitotic rate and a high MIB-1 immunostaining index. Therefore, two different entities, chronic lymphocytic leukemia/small lymphocytic lymphoma and Langerhans cell sarcoma, were detected in the same skin fragment. The patient died 3 years after initial diagnosis of chronic lymphocytic leukemia/small lymphocytic lymphoma.

Langerhans cell sarcoma arising from antecedent langerhans cell histiocytosis: A case report.

RATIONALE: Langerhans cell sarcoma (LCS) is a rare, high-grade neoplasm characterized by overtly malignant cytologic features and a poor prognosis. Herein, we present a rare case of langerhans cell histiocytosis (LCH) that later transformed into langerhans cell sarcoma 11 months after the benign mass was excised from soft tissue in the right groin. PATIENT CONCERNS: A 41-year-old patient who presented with a mass in the right groin for 3 years earlier after being bitten by ants. DIAGNOSES: The patient was diagnosed with langerhans cell sarcoma arising from antecedent langerhans cell histiocytosis. INTERVENTIONS: The patient underwent with 6 cycles of a modified etoposide, cyclophosphamide, vindesine, dexamethasone (E-CHOP) regimen. OUTCOMES: The patient is currently receiving follow-up care. LESSONS: LCH transformed into LCS is a rare case. E-CHOP as an effective first-line therapy to treat LCS cases, but, the mechanism is unclear. Due to their rarity, further data on clinical outcomes are necessary to establish the optimal treatment strategy for LCS.

KRAS mutation in secondary malignant histiocytosis arising from low grade follicular lymphoma.

BACKGROUND: Transformation of follicular lymphoma most typically occurs as diffuse large B-cell lymphoma, however other forms of transformation such as classic Hodgkin lymphoma and lymphoblastic transformation can occur. Secondary malignant histiocytosis also represents a rare form of transformation, which is thought to occur due to a process of transdifferentiation whereby the lymphoma cells exhibit lineage plasticity and lose all evidence of B-cell phenotype and instead acquire the phenotype of a histiocytic neoplasm. Little is known about the underlying genetic alterations that occur during this unusual process. Comparative genetic analysis of pre- and post-transformation/transdifferentiation would be one tool by which we could better understand how this phenomenon occurs. CASE PRESENTATION: Here we report the clinical, immunophenotypic and genetic features of a rare case of secondary malignant histiocytosis, Langerhans cell-type (Langerhans cell sarcoma) arising from a previous low grade follicular lymphoma. FISH analysis confirmed the presence of IgH/BCL2 rearrangement in both the low grade follicular lymphoma (FL) and transformed Langerhans cells sarcoma (LCS) samples, demonstrating a clonal relationship. Comparative whole exome sequencing was then performed, which identified a KRAS p.G13D mutation in the LCS that was not present in the FL. CONCLUSIONS: This report highlights genetic alterations, in particular an acquired somatic KRAS mutation, that may occur during transdifferentiation, with additional significance of KRAS mutation as a possible therapeutic target in cases which otherwise would have limited treatment options.

Synchronous case of follicular lymphoma and Langerhans cell sarcoma in the same lymph node.

Langerhans cell sarcoma (LCS) is a very rare histiocytic and dendritic cell neoplasm originating from Langerhans cells. There are case reports of histiocytic and dendritic cell neoplasms synchronously or sequentially observed in patients with malignant lymphoma. We present a case in which LCS and follicular lymphoma (FL) grade 3a were observed within the same lymph node. A 66-year-old male visited our hospital with a general malaise. Pleural effusion and systemic lymph adenopathy were detected. Biopsy of an inguinal lymph node was performed. The lymph node had regions with follicular structure and regions with acidophilic cytoplasm and large proliferating atypical cells. The tumor cells in the regions with follicular structure showed positivity for CD20 and BCL2 consistent with an FL grade 3a diagnosis. The tumor cells in the regions without follicular structure showed positivity for CD1a and S-100 and were consistent with an LCS diagnosis. Both tumor cells showed the positivity of BCL6 split by FISH. PCR detected IgH clonality in DNA collected from each region, and direct sequence analysis of cells from both tumors detected almost identical amino acid sequences. This finding is important for future research on the development of very rare histiocytic and dendritic cell neoplasms.

Liquid-based cytology in the diagnosis of Langerhans cell sarcoma: A case report.

Langerhans cell sarcoma (LCS) is an extremely rare malignant dendritic cell neoplasm with Langerhans cell differentiation. Conventional cytology, based on cell morphology alone, cannot render a cytological diagnosis of LCS because immunochemical analysis is essential to identify the Langerhans cell immunophenotype. We present a case illustrating the value of liquid-based cytology with immunocytochemistry as compared with conventional cytology, along with histological and immunohistochemical findings. A 92-year-old woman presented with a 1-month history of progressive right cervical lymphadenopathy. Cytology of a fine needle aspiration sample from the right superior internal jugular lymph node revealed proliferation of atypical, pleomorphic, and histiocytoid cells with one or more irregular-shaped nuclei. Compared with conventional cytology, liquid-based cytology demonstrated more clustered and spatial cells, slightly less marked nuclear atypia, more intense light green staining of the cytoplasm, and a clearer background. Immunocytochemical analysis of the abnormal cells revealed expression of vimentin, CD1a, langerin, CD68, and S-100. The combined morphologic and immunocytochemical results strongly indicated LCS. Histological and immunohistochemical examination of a subsequent excisional biopsy specimen closely coincided with the results of liquid-based cytology. Thus, this technique, including the use of immunocytochemistry, is very useful and valuable for the pathological diagnosis of nonepithelial and hematopoietic neoplasms. There are subtle but considerable differences in cell morphology between conventional and liquid-based cytology; these differences include clusterability, spatial findings, dyeability, and atypism as illustrated in this case of LCS.

[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.