CyclinD1 Is Useful to Differentiate Langerhans Cell Histiocytosis From Reactive Langerhans Cells

Isolated Langerhans cell histiocytosis in the stomach of adults: four-case series and literature review

Langerhans cell histiocytosis (LCH) of the stomach is rare. Moreover, it is usually found in pediatric patients with systemic diseases and may be associated with a poor prognosis. Solitary gastric LCH in adults is extremely rare and is often misdiagnosed or missed. The aim of our study was to review cases of gastric LCH and explore the characteristics of the disease further. A retrospective study of all patients admitted with solitary gastric LCH was conducted between 2013 and 2023. Clinical manifestations, endoscopic and pathological features, immunophenotypes, and molecular changes were collected from medical records. We examined four cases (one female, three males) of gastric LCH. The affected patients were between 33 and 70 years of age. Endoscopically, three patients presented with a solitary polyp or elevated lesions, whereas one patient showed no abnormalities. Under a microscope, all cases showed abnormal proliferation of histiocytoid cells infiltrating in a nested or sheet-like fashion. The tumor cells were medium-sized, with a slightly eosinophilic cytoplasm, irregular or renal-shaped nuclei, folded nuclear membranes, visible nuclear grooves, and the infiltration of inflammatory cells in the background. Immunohistochemically, all lesions expressed CD1a, S-100, langerin, and cyclinD1. One case showed diffuse BRAF V600E positivity. Follow-up data were available for all patients from 4 to 36 months, and all patients were alive without recurrence or progress at the time of manuscript preparation. Combined with previously reported data, solitary adult gastric LCH is more common in male patients, most of whom are asymptomatic or exhibit only mild gastrointestinal symptoms, with a good prognosis. Endoscopy often reveals solitary polyps or protruding lesions; rare cases may progress to multifocal/multisystem lesions, necessitating long-term close follow-up.

Thyroid Langerhans cell histiocytosis concurrent with papillary thyroid carcinoma: A case report and literature review

Langerhans cell histiocytosis (LCH) is a clonal neoplasm of myeloid dendritic cells, rarely involving the thyroid gland. Papillary thyroid carcinoma (PTC) is the most common histological subtype of thyroid cancer. We report a rare case of a 34-year-old Chinese woman who has LCH with PTC and cervical lymph node metastasis of LCH, with a review of the literature. The patient has thyroid nodules and cervical lymph node enlargement detected by neck ultrasound during physical examination. Fine needle aspiration cytology (FNAC) showed PTC with Hashimoto's thyroiditis and BRAF V600E mutation after thyroidectomy and lymph node dissection. Histopathological examination suggests that LCH was concurrent with classical PTC, accompanied by LCH cervical lymph node metastasis. No BRAF, HRAS, and TERT promoter mutations were detected in LCH metastatic lesions. The patient is in stable clinical condition currently.

Langerhans cell histiocytosis in adults: literature review

Langerhans cells histiocytosis is a variant of malignant histiocytosis. The course and symptoms vary. patients with localized forms have a better prognosis, because local therapy is effective. patients with multifocal forms of histiocytosis receive systemic drug therapy, which cures some of the patients. This review provides up-to-date data about typical presentation of the organ involvement, diagnosis, course and therapy of various forms of Langerhans cells histiocytosis.

Hallmarks of Cancer Expression in Oral Lichen Planus: A Scoping Review of Systematic Reviews and Meta-Analyses

Oral lichen planus (OLP) is a common chronic inflammatory disease of unknown etiology and likely autoimmune nature that is currently considered an oral potentially malignant disorder, implying that patients suffering from this process are at risk of developing oral cancer in their lifetime. The molecular alterations that develop in OLP and that make the affected oral epithelium predisposed to malignancy are unknown, although, as in other autoimmune diseases (ulcerative colitis, primary biliary cirrhosis, etc.), they may be linked to oncogenesis-promoting effects mediated by the inflammatory infiltrate. So far there is no in-depth knowledge on how these hallmarks of cancer are established in the cells of the oral epithelium affected by OLP. In this scoping review of systematic reviews and meta-analyses the state of evidence based knowledge in this field is presented, to point out gaps of evidence and to indicate future lines of research. MEDLINE, Embase, Cochrane Library and Dare were searched for secondary-level studies published before October 2022. The results identified 20 systematic reviews and meta-analyses critically appraising the hallmarks tumor-promoting inflammation (n = 17, 85%), sustaining proliferative signaling (n = 2, 10%), and evading growth suppressors (n = 1, 5%). No evidence was found for the other hallmarks of cancer in OLP. In conclusion, OLP malignization hypothetically derives from the aggressions of the inflammatory infiltrate and a particular type of epithelial response based on increased epithelial proliferation, evasion of growth-suppressive signals and lack of apoptosis. Future evidence-based research is required to support this hypothesis.

mRNA sequencing analysis and growth inhibitory effects of palbociclib on cell lines from canine histiocytic proliferative disorders

Canine histiocytic proliferative disorders include aggressive and fatal diseases, such as histiocytic sarcoma (HS) and histiocytosis (SyH). The molecular mechanisms underlying cell proliferation need to be elucidated for the development of effective treatments. In the present study, mRNA expression levels were comprehensively analysed in cell lines derived from localized HS, disseminated HS, SyH and Langerhans cell histiocytosis (LCH) in dogs. Based on the results obtained, the growth inhibitory effects of palbociclib, a CDK4/6 inhibitor, were verified with the cell lines in vitro and in xenograft mouse model. Hierarchical clustering and principal component analysis plots of mRNA expression profiles divided the cell lines into three groups: a localized HS group, disseminated HS/SyH group, and LCH. The results of an ingenuity pathway analysis suggested that the MAPK signalling pathway was activated in the localized HS and LCH cell lines, and the PI3K signalling pathway in the disseminated and localized HS cell lines. In all cell lines, the expression of the tumour suppressor genes TP53, CDKN2A and CDKN1A was down-regulated, whereas that of Rb was preserved. In vitro assessments revealed the growth inhibitory effects of palbociclib in all cell lines examined. In a xenograft mouse model using a cell line from disseminated HS, palbociclib exerted significant growth inhibitory effects. These results suggest the potential of palbociclib as a therapeutic drug candidate for the treatment of malignant histiocytic proliferative disorders of the dog.

Cyclin D1 expression and molecular genetic findings in periocular histiocytoses and neoplasms of macrophage-dendritic cell lineage

PURPOSE

Frequent activating mutations in the mitogen-activated protein kinase (MAPK) pathway genes have been identified in histiocytoses. MAPK signaling consistently upregulates Cyclin D1. The goal of this study was to determine whether Cyclin D1 expression by immunohistochemistry is a useful diagnostic marker for periocular histiocytoses and to further characterize their genetic basis.

DESIGN

Retrospective observational case series.

METHODS

Pathology records were searched for all patients with histiocytoses diagnosed between 1995-2020. Eleven histiocyte-rich inflammatory lesions and 10 xanthelasma served as controls. Cyclin D1 immunohistochemistry was performed on all tissues. A subset of histiocytoses was evaluated by next-generation sequencing (NGS) and droplet digital PCR (ddPCR).

RESULTS

There were 36 patients, 15 (42%) males and 21 (58%) females, with histiocytoses: 9 (25%) juvenile xanthogranuloma, 8 (22%) adult-onset asthma and periocular xanthogranuloma, 7 (19%) Langerhans cell histiocytosis, 5 (14%) Rosai-Dorfman disease, 5 (14%) xanthogranuloma not otherwise specified, 1 (3%) Erdheim-Chester disease, and 1 (3%) histiocytic sarcoma. Moderate-to-strong nuclear Cyclin D1 expression was present in ≥50% of lesional cells in histiocytoses (23/36, 64%), significantly more when compared to histiocyte-rich inflammatory lesions (0/11, 0%, P<.001) and xanthelasma (0/10, 0%, P<.001). Cyclin D1 was expressed in <10% of lesional cells in all 11 histiocyte-rich inflammatory lesions (P<.001) and all 10 xanthelasma lesions (P<.001). MAPK pathway gene mutations were detected in 12 of 14 (86%) histiocytoses successfully assayed by NGS and/or ddPCR.

CONCLUSIONS

Our study confirms that the Cyclin D1 immunohistochemical stain is a useful diagnostic marker for periocular histiocytoses, correlating with underlying mutations in MAPK pathway genes.

Utility of Cyclin D1 Immunostaining in Cutaneous Xanthogranuloma

ABSTRACT

Mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase pathway activation has recently been found to be associated with almost all Langerhans cell histiocytosis cases. In BRAF V600E mutation-positive cases, this activation is seen as a downstream activation. In addition, cyclin D1 is a downstream target of the MAPK pathway. Recent studies have argued in favor of using cyclin D1 as a potential neoplastic marker to differentiate Langerhans cell histiocytosis from other reactive Langerhans cell proliferations in the skin and lymph nodes. Therefore, we chose to study the immunohistochemical expression of cyclin D1 in cutaneous xanthogranuloma (XG) cases. Fifteen XG cases were retrieved and stained for cyclin D1, BRAF (v-raf murine sarcoma viral oncogene homolog B1), CD1a, and langerin (CD207). Twelve cases showed strong and diffuse nuclear positivity for cyclin D1, both in the XG cells and in the multinucleated osteoclast-like giant cells. Three cases showed focal weak nuclear staining for cyclin D1. All 15 cases showed negative immunoreactivity for BRAF, CD1a, and CD207. Although limited by small sample size, we conclude that most cases of cutaneous XG should show at least weak nuclear staining with cyclin D1. The histogenesis of XG is still largely unknown, and the finding of cyclin D1 positivity in a majority of cases may indicate a role for the MAPK/extracellular signal-regulated kinase pathway in cutaneous XG.

Challenges in the Histopathologic Diagnosis of Histiocytic Neoplasms

Histiocytic neoplasms, including Langerhans cell histiocytosis (LCH), Erdheim-Chester disease (ECD), and Rosai-Dorfman disease (RDD), present a diagnostic challenge due to nonspecific fibroinflammatory infiltrates and a diverse clinical presentation. The pathologist can play a key role in classification of these disorders through multidisciplinary collaboration and correlation of pathologic features with clinical and radiologic findings. The histopathologic differential diagnosis is broad, requiring knowledge of the possible diagnoses at each specific anatomic site, and a careful assessment to exclude other inflammatory and neoplastic disorders. An immunohistochemistry panel including CD163, CD1a, langerin, S100, Factor XIIIa, OCT2, and BRAF V600E can provide definitive diagnosis in LCH and RDD, whereas ECD requires classic clinical features as well as confirmation of an activating MAPK pathway mutation by genetic studies.

Histiocytic Neoplasms, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

Histiocytic neoplasms are rare hematologic disorders accounting for less than 1% of cancers of the soft tissue and lymph nodes. Clinical presentation and prognosis of these disorders can be highly variable, leading to challenges for diagnosis and optimal management of these patients. Treatment often consists of systemic therapy, and recent studies support use of targeted therapies for patients with these disorders. Observation ("watch and wait") may be sufficient for select patients with mild disease. These NCCN Guidelines for Histiocytic Neoplasms include recommendations for diagnosis and treatment of adults with the most common histiocytic disorders: Langerhans cell histiocytosis, Erdheim-Chester disease, and Rosai-Dorfman disease.

Reactive Langerhans Cell Proliferation Mimicking Langerhans Cell Histiocytosis in Association with Sézary Syndrome: A Case Report and Literature Review

Sézary syndrome (SS) is a rare type of cutaneous T-cell lymphoma (CTCL) that is characterized by erythroderma, lymphadenopathy and circulating clonal T-cells (Sézary cells). However, to our knowledge, reactive Langerhans cell (LC) proliferation mimicking Langerhans cell histiocytosis (LCH) associated with SS has not been reported. In this report, we describe an unusual case of reactive LC proliferation mimicking LCH associated with SS in a 57-year-old female patient. With complaints of recurrent skin symptoms and enlarged lymph nodes (LNs), she was admitted to our center with a presumptive diagnosis of LCH as demonstrated by LN biopsy pathology. However, other than adenopathy, no lesions were noted in any organ system commonly involved in LCH. Typical Sézary cells were identified through morphology and further confirmed by flow cytometric immunophenotyping in peripheral blood (PB) and bone marrow (BM). In addition, T-cell receptor gene rearrangement was positive, whereas the BRAF V600E gene mutation was negative in skin, LN, PB and BM. The patient was ultimately diagnosed with SS with reactive LC proliferation. This case should remind clinicians to be wary of diagnosing LCH if LCH-like pathology occurs exclusively in LNs. Moreover, morphologic, immunologic, cytogenetic and molecular biologic studies should be performed to avoid misdiagnosis.

Cyclin D1: potential utility as marker for Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is a rare disorder of unknown etiopathogenesis. Diagnosis is based on the identification of CD1a positive histiocytic infiltrate. Activation of the mitogen-activated-protein-kinase (MAPK) is constantly observed in LCH and therefore downstream markers such as cyclin D1 may be a useful marker for LCH. The aim of this study was to investigate the expression of cyclin D1 in LCH. We assessed the immunohistochemical expression of cyclin D1 (clone SP4-R) in series of 16 cases of confirmed LCH. Expression of Cyclin D1 was scored as weak, moderate, and strong nuclear staining and results were interpreted by two pathologists. The percentage of positivity was assessed. The mean age of patients was 13.7 years old with a male to female ratio of 1:3. The most common involved site was bone (n = 9; 56,3%), followed by lymph node (n = 5; 31,2%) and skin (n = 2; 12,5%). All cases showed nuclear staining for cyclin D1 with variable intensity. It was assessed moderate in 43,8% (n = 7) and strong in 56,2% (n = 9). The percentage of positive cells was >50% in 13 cases and <50% in 3 cases. Our results have shown that all cases of Langerhans cell histiocytosis from various sites express cyclin D1. This finding may be attributed to MAPK pathway activation that has been described in LCH. Otherwise, cyclin D1 is not significantly expressed in reactive Langerhans cell proliferations. Therefore, cyclin D1 immunohistochemistry may be useful as a diagnostic marker and in excluding non-neoplastic mimics of LCH.

Three additional cases of non-neural granular cell tumor with novel immunohistochemical findings

BACKGROUND

Non-neural granular cell tumor (NNGCT) is an uncommon neoplasm of controversial histogenesis and its histopathologic differential diagnosis includes, in addition to conventional GCT, other dermal tumors that may exhibit granular cell change.

METHODS

Three patients with a diagnosis of NNGCT were identified in the authors' files. Hematoxylin and eosin-stained sections and immunohistochemical studies were performed.

RESULTS

Histopathological study of the three lesions showed dermal proliferation of granular cells arranged in thick fascicles between collagen bundles. The lesions showed positivity for Factor XIIIa, CD163, CD68, NKIC3, vimentin, ALK, fascin, and cyclin D1.

CONCLUSION

To our knowledge, positivity for cyclin D1 has not been reported to date in NNGCT. In borderline cases, where the diagnosis is unclear despite histopathologic and immunohistochemical findings, positivity for cyclin D1 may favor the diagnosis of NNGCT. Further investigations to assess the differentiation of this rare neoplasm are needed.

Localized Acral Sclerosing Langerhans Cell Histiocytosis: A New Form of Presentation of Cutaneous Langerhans Cell Histiocytosis

Langerhans cell histiocytosis (LCH) is a rare proliferative disorder, more frequent in children, characterized by an abnormal accumulation of Langerhans cells admixed with eosinophils, lymphocytes, neutrophils, and macrophages. The clinical presentation is variable and depends on whether a single or multiple organs are affected. Skin lesions are common in LCH (40% of cases) and represent a frequent form of presentation (in up to 80% of cases). Cutaneous manifestations of LCH are highly variable, frequently presenting as crusted papules or scaly seborrheic-like lesions localized in the scalp. We report the first case of a localized acral sclerosing LCH, a new form of LCH. This case highlights the broad and surprising form of presentation of LCH which may be overlooked and can significantly delay its diagnosis. The development of systemic disease may occur months to years after the initial skin presentation. Prompt diagnosis and treatment may prevent progression to systemic disease, as documented in some cases.

Histiocytic and Dendritic Cell Neoplasms

Histiocytic and dendritic cell neoplasms are very rare, belonging to a group that share morphologic, immunophenotypic, and ultrastructural characteristics of mature histiocytic/dendritic neoplasms. Histiocytic and dendritic cell neoplasms may arise de novo or in association with B-cell, T-cell, or myeloid neoplasms. Recent molecular findings, particularly the discoveries of the mutations in the RAS-RAF-MEK-ERK pathway, have greatly advanced the diagnosis and treatment options. Histiocytic and dendritic cell neoplasms may closely resemble each other, non-hematopoietic neoplasms, and even reactive processes. Therefore, it is essential to understand the clinicopathologic characteristics, differential diagnoses, and pitfalls of each entity.