Langerhans Cell Histiocytosis With Unusual Hexagonal Crystals in Addition to Usual Charcot-Leyden Crystals. Report of a Patient With Possible Process of Crystal Formation and Clinical Significance of a "Necrotic" Change.

Langerhans cell histiocytosis is a rare neoplastic disorder characterized by the proliferation of Langerhans cells and often accompanied by eosinophil infiltration. Charcot-Leyden crystals, composed of galectin 10, are occasionally observed in Langerhans cell histiocytosis; however, histological images are rarely reported. We herein present a patient with Langerhans cell histiocytosis with Charcot-Leyden crystals and hexagonal crystals by describing the histologic and immunohistochemical features of a lymph node. A unique distribution of Charcot-Leyden crystals and hexagonal crystals was observed in this patient, shedding light on their possible formation process of the latter. We discuss the biological significance of eosinophilic abscesses in Langerhans cell histiocytosis and propose that these crystals may be linked to extracellular trap-cell death (ETosis). This example challenges the conventional characterization of "necrosis" in Langerhans cell histiocytosis and underscores the importance of recognizing ETosis as a potential mechanism involved in the pathogenesis of Langerhans cell histiocytosis. Further studies are underway to validate significance of these findings in a larger cohort of Langerhans cell histiocytosis patients.

Hairy Cell Leukemia-Japanese Variant: Report of a Patient and Literature Review.

Hairy cell leukemia-Japanese variant (HCL-jv) shares some features with, but differs in other features from, HCL variant. Recently, it has been pointed out that HCL-jv and splenic diffuse red pulp small B-cell lymphoma (SDRPL) possibly constitute the same disease. We report a patient with HCL-jv, in which the neoplastic cells in the resected spleen were positive for CD11c, CD103, tartrate-resistant acid phosphatase (by immunohistochemistry), and weakly positive for cyclin D3. They were negative for CD25, CD123, annexin A1, and BRAF V600E-derived protein. Meta-analysis of HCL-jv cases in the literature showed considerable variation in the expression of HCL-related molecules. Although the clinical features and pattern of splenic involvement of HCL-jv are similar to those of SDRPL, some cytomorphological and phenotypical differences can be pointed out. To confirm whether the weak expression of cyclin D3 in our case suggests a spectrum from HCL-jv to SDRPL or one of the characteristics of HCL-jv, further studies on a large number of cases are necessary.

The Expression of Insulin-Like Growth Factor 2 Messenger RNA-Binding Protein 3 in Langerhans Cell Histiocytosis and Langerhans Cell Sarcoma.

Langerhans cell neoplasms, which include Langerhans cell histiocytosis and Langerhans cell sarcoma, are tumors that originate from dendritic cells. Langerhans cell sarcoma is defined as a high-grade neoplasm with overtly malignant cytological features and the Langerhans cell-like phenotype, and generally has a poorer prognosis and more aggressive phenotype than Langerhans cell histiocytosis. Insulin-like growth factor 2 messenger RNA-binding protein 3 (IGF2BP3 or IMP3) is an oncofetal protein that is expressed in various cancer types; its expression is often associated with a poor prognosis and aggressive phenotype. Here, we used immunohistochemistry to evaluate IGF2BP3 expression in Langerhans cell neoplasms. IGF2BP3 expression was scored as negative (< 1%) or positive (≥ 1%) by immunohistochemistry. All 4 patients with Langerhans cell sarcoma (100%) and 6 of 22 pediatric (age < 18 years) patients with Langerhans cell histiocytosis (27.3%) had positive results for IGF2BP3; however, 16 of 22 pediatric patients with Langerhans cell histiocytosis (72.7%) and all 15 adult (age ≥ 18 years) patients with Langerhans cell histiocytosis (100%) had a negative result. Among patients with Langerhans cell histiocytosis, IGF2BP3 expression was independent of sex, location, prognosis, and BRAF V600E staining results. Taken together, these results indicate that IGF2BP3 expression may be a helpful marker for distinguishing Langerhans cell sarcoma from Langerhans cell histiocytosis in adult patients.

Diffuse large B-cell lymphoma (DLBCL) with significant intravascular invasion. Close resemblance of its clinicopathological features to intravascular large B-cell lymphoma, but not to DLBCL-not otherwise specified.

Intravascular large B-cell lymphoma (IVLBCL) is defined by the World Health Organization (WHO) Classification as one type of extranodal large B-cell lymphoma and it is characterized by the selective growth of lymphoma cells within blood vessels with minimal extravascular invasion. According to the criteria, however, several reported cases of IVLBCL with significant extravascular invasion cannot be classified as IVLBCL. The purpose of the present study was to assess the clinicopathological significance of the WHO criteria for IVLBCL. We characterized clinical, histopathological, and immunohistochemical features of 11 patients with extranodal diffuse large B-cell lymphoma (DLBCL) with significant intravascular invasion (DLBCL-IV), and statistically compared their features with those of 11 patients with IVLBCL and 15 patients with extranodal DLBCL with virtually no intravascular invasion (DLBCL-noIV). When compared with the DLBCL-noIV group, the DLBCL-IV group was characterized by significantly higher rates of splenomegaly, hemophagocytosis, advanced stage disease, and CD5 expression; higher average platelet count, serum lactate dehydrogenase level, and serum ferritin level. Progression-free survival was significantly shorter in the DLBCL-IV group than the DLBCL-noIV group. In contrast, there were no significant differences in clinicopathological features between the DLBCL-IV and the IVLBCL groups. Our study suggests that DLBCL-IV should be regarded as IVLBCL-related.

Localized lymphadenopathy with myelodysplastic syndrome associated with tuberculosis.

We report the case of a man who developed myelodysplastic syndrome (MDS) and refractory cytopenia of unilineage dysplasia, 5 months after aortic valve replacement surgery. He also developed fever of unknown origin. After bone marrow- and other laboratory examinations, he was diagnosed with tuberculosis.

A Case Report of Umbilical Vein Varix with Thrombosis: Prenatal Ultrasonographic Diagnosis and Management.

Umbilical vein varix (UVV) is a very rare cord anomaly associated with intrauterine fetal death and fetal anomaly. We describe a case of extra-abdominal UVV with thrombosis. UVV was diagnosed at 23 weeks of gestation for the first time by ultrasonographic screening. Peak systolic velocity (PSV) near the UVV was partially increased up to about 100 cm/s, and blood flow was not detected in one of the umbilical arteries at 28 weeks of gestation. Therefore, the mother was hospitalized to monitor alterations of the PSV of the UVV frequently. Because the PSV of the UVV showed a sudden rapid increase up to about 150 cm/s at 32 weeks of gestation, she underwent emergent cesarean section on the same day to avoid sudden umbilical cord occlusion. The infant's birth weight was 1,744 g, and the Apgar scores were 8 and 9 at 1 and 5 minutes, respectively. The pathological examination showed UVV with thrombosis and an occlusion in one of the umbilical arteries. The neonatal laboratory data showed no coagulopathy. Based on our experience with this case, frequent ultrasonographic examination should be performed to detect the acute thrombosis in the case of extra-abdominal UVV, especially during the preterm period.

Immunohistochemical Reappraisal Regarding the Frequency of Primary Salivary Gland Follicular Lymphoma.

Although it has been described that extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT lymphomas) are the most common type among primary salivary gland lymphomas (SGLs), some studies revealed that the frequency of follicular lymphomas (FLs) was as high as that of MALT lymphomas. However, it has been reported that many of these FLs may have developed in lymph nodes attached to the capsule of the glands or intraglandular lymph nodes. Clinical, histological, immunohistochemical, and cytogenetic features of 11 SGL cases, which were extracted from our surgical pathology file consisting of consecutive pathology cases, were reevaluated to further characterize whether they were actually primary SGLs. There were 3 (27%) cases of FLs, 5 (46%) cases of MALT lymphomas, and 3 (27%) cases of diffuse large B-cell lymphomas. Although all of our FL cases fulfilled the criteria of primary SGL, tumors of several FL cases were surrounded by podoplanin (by D2-40)-positive elongated vessels or linear structures indicative of nodal subcapsular sinuses (open or remnant). This finding would support the aforementioned possibility, and podoplanin staining is necessary before concluding that a FL is a primary SGL.

FGFRL1 deficiency reduces motility and tumorigenic potential of cells derived from oesophageal squamous cell carcinomas.

Oesophageal squamous cell carcinoma (ESCC) is an aggressive cancer that resulted in ~400,000 mortalities worldwide in 2012. It was reported previously that fibroblast growth factor receptor-like 1 (FGFRL1) is highly expressed in ESCC patients with lymph node metastasis and poor prognosis accordingly. FGFRL1 is an FGFR that lacks tyrosine kinase activity, whereas the activity is critical for other FGFRs to activate intracellular signalling. The mechanism by which FGFRL1 promotes the aggressiveness of ESCCs is unknown. In the present study, two independent FGFRL1-deficient cell lines were generated from human ESCC KYSE520 cells, in order to investigate the relationship of FGFRL1 with the aggressiveness of ESCCs. FGFRL1-deficiency did not affect proliferation of KYSE520 cells in vitro. However, a xenograft mouse model demonstrated that FGFRL1-deficiency decelerated tumour growth in vivo. The haematoxylin-eosin staining identified that FGFRL1-deficient cells formed well-differentiated squamous cell carcinomas, whereas wild-type cells formed moderately differentiated squamous cell carcinomas. Microarray analysis of mRNA expression revealed that FGFRL1-depletion resulted in decreased expression of proteins associated with motility and invasion of tumour cells, matrix metalloproteinase-1 and fibroblast growth factor binding protein 1. The wound-healing assay indicated that depleting FGFRL1 reduced cell motility. Furthermore, the invasiveness of FGFRL1-deficient cells was lesser than that of wild-type KYSE520 cells. In the FGFRL1-deficient KYSE520 cells, actin filaments around the nucleus were observed sparsely, whereas the filaments along the plasma membranes were observed as frequently as those in the parent KYSE520 cells. These results demonstrate that FGFRL1 may be involved in regulation of protein expression, actin filament assembly and tumorigenic potential of ESCC cells.

Follicular lymphoma with plasmacytic differentiation accompanied by monoclonal IgG gammopathy.

A 59-year-old woman presented with high serum total protein, detected on a screening examination. Laboratory tests revealed high plasma levels of M-protein (IgG-λ), and FDG-PET/CT revealed systemic lymph node swelling and a large tumorous mass in the abdominal cavity. Bone marrow aspirates contained 8.4% plasma cells and approximately 30% abnormal small lymphocytes. A biopsy of the left supraclavicular lymph node was initially interpreted as lymphoplasmacytic lymphoma (LPL). However, chromosomal analysis of the lymph node demonstrated an unusual karyotype with t (14;18) (q32;q21). FISH analysis for the IgH-BCL2 fusion gene was positive. Furthermore, the MYD88 L265P mutation was not detected in tumor cells. Based on these findings, this case was determined to be a type of follicular lymphoma with plasmacytic differentiation. We considered that this case was an important example emphasizing the importance of karyotypic examination for lymphoma classification.

Langerhans Cell Histiocytosis and Langerhans Cell Sarcoma: Current Understanding and Differential Diagnosis.

Langerhans cell (LC) histiocytosis (LCH) and LC sarcoma (LCS) are proliferative processes consisting of cells having morphologic and phenotypic features of Langerhans cells (LCs), although the latter may have lost some of these features. Because neoplastic nature of LCH as well as LCS is more likely by recent studies, a category of LC hyperplasia can be better characterized. LCH and LCS are rarely seen in daily pathology practice, but it is important to accurately characterize these lesions. For this purpose, an outline covering proliferations of LC and related cells was constructed. The scheme of this outline is based especially on evaluating borderline lesions, neoplastic trans-differentiation, and degree of similarity with the normal counter-parts. In addition, the organization and update of the current classification scheme for histiocytic and dendritic-cell proliferations is presented.

Intravascular Large B-Cell Lymphoma Coexisting with an Ovarian Carcinoma.

We report an incidental case of intravascular large B-cell lymphoma (IVLBCL) coexisting with an ovarian carcinoma in a 76-year-old woman. She visited our hospital with difficulty in defecation. Magnetic resonance imaging and computerized tomography scan revealed a solid and cystic mass probably arising from the left ovary. Gross examination of the tumor obtained by an exploratory surgery showed a solid area in a simple cyst. The ovarian tumor was diagnosed as a high-grade serous carcinoma (HGSC). Early in the post-operative course, this patient developed fever of unknown origin with central nervous system manifestations. Magnetic resonance imaging of the brain showed multiple space-occupying lesions. When we reviewed the histological sections, atypical lymphocytes were found in the lumina of small vessels of almost the entire ovary. These cells were positive for CD20 and CD79a by immunohistochemistry. A diagnosis of IVLBCL coexisting with HGSC was finally made. Although radiation therapy for brain lesions was performed and rituximab was administered, she died two months after the operation. To the best of our knowledge, this is the first case of IVLBCL incidentally identified in HGSC through microscopic examination. This case serves to create awareness of the rare event where IVLBCL may involve the ovary of patients who also have carcinoma in the organ.

A retrospective study of patients with follicular lymphoma (FL): identification of in situ FL or FL-like B cells of uncertain significance in lymph nodes resected at the time of previous surgery for carcinomas.

BACKGROUND AND AIMS: In situ follicular lymphoma (iFL)/intrafollicular neoplasia and follicular lymphoma (FL)-like B cells of uncertain significance represent proliferation of Bcl-2/t(14;18)-positive B cells solely in the germinal centres. The condition is interpreted as an early event in the multi-step lymphomagenesis of FL. The aim of this study is to examine the issue more specifically. METHODS: We reviewed medical history of FL patients in whom thoracoabdominal surgery with lymphadenectomy had been performed for management of carcinomas. These previously resected lymph nodes as well as the current FL nodes were analysed by immunohistochemistry, fluorescent in situ hybridisation, and PCR amplification with direct sequencing. RESULTS: We studied four such FL patients from a total of 150 patients with FL; all had iFL in the previously resected lymph nodes. Clonal relation was verified and suggested in one case each. The time from lymphadenectomy to the diagnosis of FL was 23-120 months. There appeared to be a reverse correlation between the rate of Bcl-2-positive follicle proliferation and the time from surgery to diagnosis of FL. CONCLUSIONS: Although the rate for development of FL in individuals having iFL has been reported to be low from prospective studies, the present data indicate that follow-up studies for a longer period is necessary; the rate of Bcl-2-positive follicle proliferation could be a factor to predict development of FL in prospective studies. Such a retrospective study may contribute to elucidate mechanism(s) involved in lymphomagenesis of FL.

High viral load of Merkel cell polyomavirus DNA sequences in Langerhans cell sarcoma tissues.

BACKGROUND: Langerhans cell (LC) sarcoma (LCS) is a high-grade neoplasm with overtly malignant cytologic features and an LC phenotype. We very recently suggested that LC behaves as a reservoir for common dermotropic Merkel cell polyomavirus (MCPyV) and determined the relationship between LC histiocytosis (LCH), which has an underlining oncogenic capacity, and MCPyV as a trigger for a reactive process rather than a neoplastic process. We propose LC to be a reservoir for MCPyV and hypothesize that some LCS subtypes may be related to the MCPyV agent. FINDINGS: We examined seven LCS tissues using multiplex quantitative PCR (Q-PCR) and immunohistochemistry with anti MCPyV large-T (LT) antigen antibody. High viral loads of MCPyV DNA sequences (viral load = relative levels of MCPyV) were detected (0.328-0.772 copies/cell (Merkel cell carcinoma (MCC) = 1.0)) using Q-PCR in 43% (3/7) tissues, but LT antigen expression was not observed (0/7). CONCLUSIONS: Frequent MCPyV-DNA amplification suggests that LCS in some patients may be related to MCPyV infection. Moreover, the higher viral load of LCS (median, 0.453 copies/cell) than low load of LCH (0.003, median of 12 cases) (P < 0.01) may suggest a virally induced tumorigenic process in some LCS. Although the absence of LT antigen expression may indicate a different role for MCPyV in this pathology, some subtypes of LCS may develop in the background of MCPyV-infected LC. To the best of our knowledge, this is the first report on the relationship between MCPyV and LCS. The recent discovery of MCPyV opened new therapeutic avenues for MCC. These data open novel possibilities for therapeutic interventions against LCS.

[Flow cytometry].

Flow cytometry (FCM), which has been elaborated and refined in conjunction with the development of both immunological engineering and information technology, is now indispensable for the diagnosis and treatment of patients with leukemia and lymphoma. FCM had better be regarded as being complementary to, but not competitive with, immunohistochemistry. Histopathologic features are often useful not only for interpretation of the FCM data, but also in evaluating quality of samples used for FCM. In interpretation of the data, one should not put excessive emphasis on bar chart, because conversion of dot plotting to it is associated with loss of many data. Although FCM gives digital data on each thousands of cells, correct interpretation of the data requires an analogue standpoint.

Epstein-Barr virus-positive diffuse large B-cell lymphoma of the elderly complicated by the onset of acute myeloid leukemia.

We herein describe the case of a 62-year-old woman who presented with anemia and an 8-month history of weight loss. Bone marrow aspiration showed increased myeloblasts. The histopathology findings of biopsy specimens of the right cervical lymph node and intestinal mass indicated B-lymphoproliferative disorder (B-LPD) with Hodgkin lymphoma-like morphologic features and polymorphous diffuse large B-cell lymphoma (DLBCL), respectively. In addition, both types of lymphoma cells were positive for Epstein-Barr virus (EBV)-encoded small RNA-1. The patient was diagnosed with EBV-associated B-LPD and simultaneous acute myeloid leukemia (AML). This is the first case of a patient diagnosed with simultaneous EBV-positive DLBCL of the elderly and AML.

Incidence and clinical significance of aberrant T-cell marker expression on diffuse large B-cell lymphoma cells.

INTRODUCTION: Aberrant expression of T-cell markers is occasionally observed in B-cell lymphomas. We conducted a retrospective study to establish its incidence and to determine its relationship with clinical features of patients with diffuse large B-cell lymphoma (DLBCL). PATIENTS AND METHODS: We reviewed DLBCL patients diagnosed between January 2002 and April 2009. Patients fulfilled the following criteria: (1) age >18 years, (2) HIV negative, (3) B-cell lymphoma confirmed by restricted expression of surface immunoglobulin light chains by flow cytometry (FCM). Aberrant T-cell marker expression (ATCME) was defined as positivity for CD2, CD3, CD4, CD7, and/or CD8 on DLBCL cells by FCM. Phenotyping was also performed by immunohistochemistry (IHC). Patients were grouped according to positive or negative ATCME and their clinical features including survival were compared. RESULTS: Of 150 patients, 11 (7.3%) showed ATCME; CD2 and CD7 were most often expressed. ATCME was less often detected and the signal was weaker using IHC. There were no statistically significant differences in clinical features between the two groups. CONCLUSIONS: FCM may be useful to detect ATCME in a small amount of lymphoma cells. The mechanism responsible for ATCME, and whether it contributes in any way to the pathogenesis of B-cell neoplastic transformation, requires clarification.