T-cell receptor gamma gene rearrangement analysis of classic Hodgkin lymphoma using a BIOMED-2 assay: a paraffin-embedded tissue analysis of one hundred cases.

In the new WHO classifications of haematolymphoid tumours (WHO-HAEM5), classic Hodgkin lymphoma (cHL) is categorized into B-cell lymphoid proliferations and lymphomas. Although the majority of Hodgkin Reed-Sternberg (HRS) cells are of germinal center B-cell origin with some defects of B-cell transcription factors, they rarely express T-cell antigens or cytotoxic molecules. Clonality analyses on cHL samples using BIOMED-2 have been reported by several groups; however, those studies were only focused on Ig regions, including IgH, Ig-kappa, and Ig-lambda, and TCR-γ clonality analysis of cHL has not yet been explored. Here, we investigated TCR-γ gene rearrangement for one hundred cases using a PCR-based method. Four of one hundred (4%) cases showed TCR-γ clonal peaks. Of these, three were at an advanced stage and one patient died of the disease. To clarify whether HRS cells showed T-cell clonality or not, we performed PCR analysis using DNAs of microdissected HRS cells. Three samples showed identical clonal peaks with bulk specimens. Our results indicate that cHL is a heterogeneous disease of mainly B-cell and rarely T-cell origin with a special phenotype. Further molecular studies are warranted.

Atypical lymphoplasmacytic and immunoblastic proliferation: A Systematic Review.

Atypical lymphoplasmacytic and immunoblastic proliferation (ALPIBP) was first reported in 1984 as characteristic histological findings in lymph nodes associated with autoimmune diseases, but it has not been clearly defined to date. To summarize the histological characteristics and clinical diagnoses associated with ALPIBP, we searched MEDLINE and EMBASE for all peer-reviewed articles using keywords including "atypical lymphoplasmacytic and immunoblastic lymphadenopathy" from their inception to December 27, 2023. We also summarized the courses of three cases with a pathological diagnosis of ALPIBP. Nine articles with 52 cases were included. Among the total of 55 cases, including the three from our institution, the median age of the cases was 63.5 years with a female predominance (69.5%). Lymphadenopathy was generalized in 65.6% and regional in 34.4% of cases. RA (24.4%), SLE (24.4%), and autoimmune hemolytic anemia (20.0%), were common clinical diagnoses. A combination of cytotoxic chemotherapy was used in 15.6% of cases due to the suspicion of malignancy. Nodal T-follicular helper cell lymphoma, angioimmunoblastic type, methotrexate-associated lymphoproliferative disorders, and IgG4-related diseases were listed as important diseases that need to be pathologically differentiated from ALPIBP. This review summarizes the current understanding of the characteristics of ALPIBP. Given that underrecognition of ALPIBP could lead to overdiagnosis of hematological malignancy and unnecessary treatment, increased awareness of the condition in pathologists and clinicians is crucial.

Copy Number Analysis of 9p24.1 in Classic Hodgkin Lymphoma Arising in Immune Deficiency/Dysregulation.

A subset of patients with rheumatoid arthritis receiving methotrexate develop immune deficiencies and dysregulation-associated lymphoproliferative disorders. Patients with these disorders often exhibit spontaneous regression after MTX withdrawal; however, chemotherapeutic intervention is frequently required in patients with classic Hodgkin lymphoma arising in immune deficiency/dysregulation. In this study, we examined PD-L1 expression levels and 9p24.1 copy number alterations in 27 patients with classic Hodgkin lymphoma arising from immune deficiency/dysregulation. All patients demonstrated PD-L1 protein expression and harbored 9p24.1 copy number alterations on the tumor cells. When comparing clinicopathological data and associations with 9p24.1 copy number features, the copy gain group showed a significantly higher incidence of extranodal lesions and clinical stages than the amplification group. Notably, all cases in the amplification group had latency type II, while 6/8 (75%) in the copy gain group had latency type II, and 2/8 (25%) had latency type I. Thus, a subset of the copy-gain group demonstrated more extensive extranodal lesions and higher clinical stages. This finding speculates the presence of a genetically distinct subgroup within the group of patients who develop immune deficiencies and dysregulation-associated lymphoproliferative disorders, which may explain certain characteristic features.

Diagnostic challenges of the idiopathic plasmacytic lymphadenopathy (IPL) subtype of idiopathic multicentric Castleman disease (iMCD): Factors to differentiate from IgG4-related disease.

AIMS AND METHODS: Idiopathic multicentric Castleman disease (iMCD) is currently considered to be classified into three clinical subtypes, including idiopathic plasmacytic lymphadenopathy (IPL), thrombocytopaenia, anasarca, fever, reticulin fibrosis/renal dysfunction, organomegaly (TAFRO) and not otherwise specified (NOS). Among the three, iMCD-IPL closely mimics IgG4-related disease (IgG4-RD). In diagnosing IgG4-RD, it is sometimes challenging to distinguish iMCD-IPL patients that also meet the histological diagnostic criteria for IgG4-RD. In this study, we focused on the number of IgG4-positive cells in the lymph nodes and analysed the relationship with laboratory findings to distinguish iMCD-IPL from IgG4-RD. Thirty-nine patients with iMCD-IPL and 22 patients with IgG4-RD were included. RESULTS: Among the cases considered to be iMCD-IPL, 33.3% (13/39) cases also met the histological diagnostic criteria for IgG4-RD and serum IgG4 levels were not different between the two groups. However, the serum IgG4/IgG ratio was significantly higher in IgG4-RD, with a cut-off value of 19.0%. Additionally, a significant positive correlation between serum IgG levels and the number of IgG4-positive cells was observed in iMCD-IPL (p=0.001). The serum IgG cut-off value for distinguishing iMCD-IPL meeting histological criteria for IgG4-RD from other iMCD-IPL was 5381 mg/dL. CONCLUSIONS: iMCD-IPL cases with high serum IgG levels (>5000 mg/dL) were likely to meet the diagnostic criteria for IgG4-RD because of the numerous IgG4-positive cells observed. A combination of clinical presentations, laboratory values including the serum IgG4/IgG ratios and histological analysis is crucial for diagnosis of IgG4-RD and iMCD-IPL.

Analysis of Notch1 protein expression in methotrexate-associated lymphoproliferative disorders.

Methotrexate (MTX)-associated lymphoproliferative disorder (MTX-LPD) is a lymphoproliferative disorder in patients treated with MTX. The mechanism of pathogenesis is still elusive, but it is thought to be a complex interplay of factors, such as underlying autoimmune disease activity, MTX use, Epstein-Barr virus infection, and aging. The NOTCH genes encode receptors for a signaling pathway that regulates various fundamental cellular processes, such as proliferation and differentiation during embryonic development. Mutations of NOTCH1 have been reported in B-cell tumors, including chronic lymphocytic leukemia/lymphoma, mantle cell lymphoma, and diffuse large B-cell lymphoma (DLBCL). Recently, it has also been reported that NOTCH1 mutations are found in post-transplant lymphoproliferative disorders, and in CD20-positive cells in angioimmunoblastic T-cell lymphoma, which might be associated with lymphomagenesis in immunodeficiency. In this study, to investigate the association of NOTCH1 in the pathogenesis of MTX-LPD, we evaluated protein expression of Notch1 in nuclei immunohistochemically in MTX-LPD cases [histologically DLBCL-type (n = 24) and classical Hodgkin lymphoma (CHL)-type (n = 24)] and de novo lymphoma cases [DLBCL (n = 19) and CHL (n = 15)]. The results showed that among MTX-LPD cases, the expression of Notch1 protein was significantly higher in the DLBCL type than in the CHL type (P < 0.001). In addition, among DLBCL morphology cases, expression of Notch1 tended to be higher in MTX-LPD than in the de novo group; however this difference was not significant (P = 0.0605). The results showed that NOTCH1 may be involved in the proliferation and tumorigenesis of B cells under the use of MTX. Further research, including genetic studies, is necessary.

Distribution and clinical impact of molecular subtypes with dark zone signature of DLBCL in a Japanese real-world study.

The distribution and clinical impact of cell-of-origin (COO) subtypes of diffuse large B-cell lymphoma (DLBCL) outside Western countries remain unknown. Recent literature also suggests that there is an additional COO subtype associated with the germinal center dark zone (DZ) that warrants wider validation to generalize clinical relevance. Here, we assembled a cohort of Japanese patients with untreated DLBCL and determined the refined COO subtypes, which include the DZ signature (DZsig), using the NanoString DLBCL90 assay. To compare the distribution and clinical characteristics of the molecular subtypes, we used a data set from the cohort of British Columbia Cancer (BCC) (n = 804). Through the 1050 patient samples on which DLBCL90 assay was successfully performed in our cohort, 35%, 45%, and 6% of patients were identified to have germinal center B-cell-like (GCB) DLBCL, activated B-cell-like (ABC) DLBCL, and DZsig-positive (DZsigpos) DLBCL, respectively, with the highest prevalence of ABC-DLBCL, differing significantly from the BCC result (P < .001). GCB-DLBCL, ABC-DLBCL, and DZsigpos-DLBCL were associated with 2-year overall survival rates of 88%, 75%, and 66%, respectively (P < .0001), with patients with DZsigpos-DLBCL having the poorest prognosis. In contrast, GCB-DLBCL without DZsig showed excellent outcomes after rituximab-containing immunochemotherapy. DZsigpos-DLBCL was associated with the significant enrichment of tumors with CD10 expression, concurrent MYC/BCL2 expression, and depletion of microenvironmental components (all, P < .05). These results provide evidence of the distinct distribution of clinically relevant molecular subtypes in Japanese DLBCL and that refined COO, as measured by the DLBCL90 assay, is a robust prognostic biomarker that is consistent across geographical areas.

A case of coexistent poorly differentiated adenosquamous carcinoma (glassy cell carcinoma), usual-type adenocarcinoma, and squamous cell carcinoma in situ of the cervix.

Poorly differentiated adenosquamous carcinoma (glassy cell carcinoma) of the cervix is extremely rare, accounting for 1-2% of all cervical cancers. Herein, we report a case with coexistent poorly differentiated adenosquamous carcinoma (glassy cell carcinoma), "usual-type" adenocarcinoma, and squamous cell carcinoma in situ of the cervix. A female patient in her 60 s was referred to our hospital and diagnosed with poorly differentiated adenosquamous carcinoma based on cervical cytology and biopsy. The tumor was classified as clinical stage IB1 cervical cancer following magnetic resonance imaging; radical hysterectomy was performed. Histopathological examination revealed poorly differentiated adenosquamous carcinoma (glassy cell carcinoma), usual-type adenocarcinoma, and squamous cell carcinoma in situ, all coexisting. All carcinoma regions showed identical sizes to high-risk human papillomavirus (HPV) in fragment analysis. The patient is currently alive, without evidence of recurrence, 31 months post surgery. In this case, three different carcinomas coexisted. Fragment analysis of the patient's HPV status suggested that all carcinomas were related to an infection with the same high-risk HPV type. To determine the precise mechanism of tumor development, i.e., whether the tumors were of the mixed or collision type, further studies are needed, including clonal analysis for the loss of heterozygosity pattern.

Idiopathic Plasmacytic Lymphadenopathy Forms an Independent Subtype of Idiopathic Multicentric Castleman Disease.

Idiopathic multicentric Castleman disease (iMCD) is a type of Castleman disease that is not related to KSHV/HHV8 infection. Currently, iMCD is classified into iMCD-TAFRO (thrombocytopenia, anasarca, fever, reticulin fibrosis, and organomegaly) and iMCD-NOS (not otherwise specified). The former has been established as a relatively homogeneous disease unit that has been recently re-defined, while the latter is considered to be a heterogeneous disease that could be further divided into several subtypes. In 1980, Mori et al. proposed the concept of idiopathic plasmacytic lymphadenopathy (IPL), a disease presenting with polyclonal hypergammaglobulinemia and a sheet-like proliferation of mature plasma cells in the lymph nodes. Some researchers consider IPL to be a part of iMCD-NOS, although it has not been clearly defined to date. This is the first paper to analyze iMCD-NOS clinicopathologically, to examine whether IPL forms a uniform disease unit in iMCD. Histologically, the IPL group showed prominent plasmacytosis and the hyperplasia of germinal centers, while the non-IPL group showed prominent vascularity. Clinically, the IPL group showed significant thrombocytosis and elevated serum IgG levels compared to the non-IPL group (p = 0.007, p < 0.001, respectively). Pleural effusion and ascites were less common in the IPL group (p < 0.001). The IPL group was more likely to have an indolent clinical course and a good response to the anti-IL-6 receptor antibody, while the non-IPL counterpart frequently required more aggressive medical interventions. Thus, the IPL group is a clinicopathologically uniform entity that forms an independent subtype of iMCD.

Clinicopathological characteristics of gastric IgG4-related disease: Systematic scoping review.

BACKGROUND AND AIM: Gastric IgG4-related disease (IgG4-RD) can mimic malignancy, submucosal tumors (SMT), and ulcers, leading to over-triage and unnecessary medical interventions such as gastrectomy. The variability in the clinicopathological presentation of IgG4-related disease is not yet well defined, posing a diagnostic challenge. METHODS: Following the PRISMA Extension for Scoping Reviews, we searched MEDLINE and EMBASE for all peer-reviewed articles using keywords including "gastritis," "stomach," "gastrointestinal stromal tumor," and "IgG4-RD" from their inception to December 28, 2021. RESULTS: Thirty-nine articles, including 2 observational studies and 42 cases, were included in the systematic review. While bottom-heavy lymphoplasmacytic mucosal infiltration is a characteristic finding of gastric IgG4-RD, it was only present in less than half of the patients in the observational studies. Patients with gastric IgG4-RD were more likely to be diagnosed with gastrointestinal stromal tumor (GIST), gastric cancer, or peptic ulcer disease and their clinical course involved resection (51.3%) or even gastrectomy. Diagnosis of gastric IgG4-RD was most frequently made by post-operative pathological analysis. CONCLUSION: This systematic review summarizes the current understanding of the characteristics of gastric IgG4-RD. Increased awareness of gastric IgG4-RD as a differential diagnosis of gastric SMT or ulcers among clinicians is crucial in order to reduce unnecessary high-risk, invasive interventions.

Clinical characteristics and outcomes of IgG4-positive marginal zone lymphoma: Systematic scoping review.

Immunoglobulin G4 (IgG4)-positive marginal zone lymphoma (MZL) is rare and undefined. It is unclear whether IgG4-positive MZLs have as favorable an outcome as MZLs in general. Also, correlation with IgG4-related disease (IgG4-RD) and IgG4-positive MZLs is unknown. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews, we searched MEDLINE and EMBASE for all peer-reviewed articles using keywords including"IgG4" and "marginal zone lymphoma" from their inception to February 20, 2022. Twenty-two articles, including six observational studies and 24 cases from 16 case reports and case series, were included. Only one study had a comparative group, and the other five were exploratory observational studies. IgG4-positive MZLs commonly occurred in males (83.3%). It primarily involved ocular adnexa (41.7%) and skin (29.2%). Only 29.2% had concurrent IgG4-RD, and no expiration was noted. While most cases were treated with excision, resection, or clinical observation, 21.7% received rituximab-cyclophosphamide, doxorubicin, vincristine, and prednisone as a first-line treatment. This systematic review summarizes the current understanding of the characteristics of IgG4-positive MZLs. While there seems to be IgG4-RD-related and de novo IgG4-positive MZLs, future research needs to clearly define MZL with polyclonal IgG4-positive cells and IgG4-producing lymphoma. Further studies are critical to clarifying long-term prognosis and optimal surveillance planning.

Historical and pathological overview of Castleman disease.

Castleman disease consists of several lymphoproliferative subtypes that share some histological features in the lymph nodes. On the other hand, numerous clinical findings and etiologies make the disease challenging to understand. The origin of the disease is the hyaline vascular-type unicentric Castleman disease (UCD), first reported by Benjamin Castleman et al. in 1954. Although UCD is characterized by localized lesions and lack of symptoms, multicentric Castleman disease (MCD) with multiple lesions and systemic symptoms was reported by Frizzera in 1983. MCD is further divided according to KSHV/HHV8 infection status. In KSHV/HHV8-related MCD, viral infection signals lead to excessive cytokine production, and cause clinical and pathologic abnormalities. Some cases of plasma cell-type KSHV/HHV8-negative MCD can be found in association with POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, M-proteins, and skin changes), which is a paraneoplastic syndrome. The others are idiopathic MCD, which are currently considered a heterogeneous group of diseases with overlapping pathological and clinical features. In this article, we summarize the historical evolution of Castleman disease to help understand the disease concept. We also review the latest ideas and definitions of the subtypes within the MCD spectrum and summarize the histopathological findings.

Idiopathic multicentric Castleman disease with positive antiphospholipid antibody: atypical and undiagnosed autoimmune disease?

Idiopathic multicentric Castleman disease (iMCD) is a systemic disorder characterized by systemic inflammation and organ dysfunction associated with an increase in pro-inflammatory cytokines. Some patients with iMCD are positive for autoantibodies, although their significance and relationship with specific associated autoimmune diseases are unclear. This study retrospectively analyzed the clinicopathological features of iMCD patients focusing on autoantibodies. Among 63 iMCD patients in our database, 19 were positive for at least one autoantibody. Among the 19, we identified five with plasma cell type (PC)-iMCD lymph node histopathology and positive anti-phospholipid antibodies. These patients were likely to have thrombocytopenia, anasarca, fever, reticulin fibrosis or renal insufficiency, organomegaly (TAFRO) symptoms, and thrombotic events. The present study suggests that patients with undiagnosed or atypical autoimmune diseases, including anti-phospholipid syndrome (APS), were treated for iMCD. APS may present with thrombocytopenia or even multi-organ failure, which overlap with clinical presentations of iMCD. Due to differences in the treatment regimen and follow-up, recognition of the undiagnosed autoimmune disease process in those suspected of iMCD is essential. Our study highlights the importance of complete exclusion of differential diagnoses in patients with iMCD in their diagnostic workup.

Clinicopathologic Analysis of Sinonasal Inverted Papilloma, with Focus on Human Papillomavirus Infection Status.

Sinonasal inverted papilloma (SNIP) can recur; however, the factors related to tumor recurrence remain unclear. This study aimed to analyze risk factors, including human papillomavirus (HPV) infection, as well as other factors associated with SNIP recurrence. Thirty-two patients who were diagnosed with SNIP and underwent surgery between 2010 and 2019 were enrolled: 24 men and 8 women, with a mean age of 59.2 years. The mean follow-up was 57.3 months. Demographics and information about history of smoking, diabetes mellitus (DM), hypertension, allergic rhinitis, alcohol consumption, tumor stage, surgical approach, and recurrence were reviewed retrospectively. Specimens were investigated using polymerase chain reaction to detect HPV DNA (high-risk subtypes: 16, 18, 31, 33, 35, 52b, and 58; low-risk subtypes: 6 and 11). Seven patients (21.9%) experienced recurrence. HPV DNA was detected in five (15.6%) patients (high-risk subtypes, n = 2; low-risk subtypes, n = 3). Patients with recurrence of SNIP had a higher proportion of young adults and displayed higher rates of HPV infection, DM, and advanced tumor stage than those without recurrence. HPV infection, young adulthood, DM, and advanced tumor stage could be associated with a high recurrence rate, which suggests that patients with these risk factors could require close follow-up after surgery.

PD-L1 expression is associated with the spontaneous regression of patients with methotrexate-associated lymphoproliferative disorders.

BACKGROUND: Most patients with methotrexate-associated lymphoproliferative disorder (MTX-LPD) show diffuse large B-cell lymphoma (DLBCL) or classic Hodgkin lymphoma (CHL) types. Patients with MTX-LPD often have spontaneous remission after MTX discontinuation, but chemotherapeutic intervention is frequently required in patients with CHL-type MTX-LPD. In this study, we examined whether programmed cell death-ligand 1 (PD-L1) expression levels were associated with the prognosis of MTX-LPD after MTX discontinuation. METHODS: A total of 72 Japanese patients diagnosed with MTX-LPD were clinicopathologically analyzed, and immunohistochemical staining of PD-L1 was performed in 20 DLBCL-type and 24 CHL-type MTX-LPD cases to compare with the clinical course. RESULTS: PD-L1 was expressed in 5.0% (1/20) of patients with DLBCL-type MTX-LPD, whereas it was expressed in 66.7% (16/24) of the patients with CHL-type MTX-LPD in more than 51% of tumor cells. Most CHL-type MTX-LPD patients with high PD-L1 expression required chemotherapy owing to exacerbations or relapses after MTX discontinuation. However, no significant differences in clinicopathologic findings at diagnosis were observed between PD-L1 high- and low-expression CHL-type MTX-LPD. CONCLUSION: PD-L1 expression was significantly higher in patients with CHL-type than DLBCL-type MTX-LPD, suggesting the need for chemotherapy in addition to MTX discontinuation in CHL-type MTX-LPD patients to achieve complete remission. No association was observed between PD-L1 expression levels and clinical findings at diagnosis, suggesting that PD-L1 expression in tumor cells influences the pathogenesis of CHL-type MTX-LPD after MTX discontinuation.

Investigation of IgG4-positive cells in idiopathic multicentric Castleman disease and validation of the 2020 exclusion criteria for IgG4-related disease.

Patients with plasma cell type idiopathic multicentric Castleman disease (PC-iMCD) often show elevated serum IgG4 levels and IgG4-positive cell infiltration in tissues due to overproduction of interleukin-6, and may meet the diagnostic criteria for IgG4-related disease (IgG4-RD). Although PC-iMCD has been listed as a major exclusion disease for IgG4-RD, distinguishing between these diseases is challenging due to a lack of highly specific diagnostic biomarkers. In 2020, we proposed exclusion criteria of IgG4-RD mimickers. In this paper, we validated the accuracy of the criteria in excluding one of the mimickers, PC-iMCD, from IgG4-RD. Validation was performed on 57 PC-iMCD patients (39 presenting lymph node lesions and 19 with lung lesions) and 29 IgG4-RD patients (22 presenting lymph node lesions and seven with lung lesions). According to our results, 20.5% of the PC-iMCD patients with lymph node lesions and 42.1% of those with lung lesions met the diagnostic criteria for IgG4-RD. All these patients with PC-iMCD were excluded from a diagnosis of IgG4-RD by the proposed criteria. Additionally, 6.9% of IgG4-RD patients met the exclusion criteria. Thus, if the exclusion criteria are met, diagnosis should be made based on a combination of findings including organ distribution of disease, response to steroid therapy, and other pathological findings.

Cytopathological Findings of Secretory Carcinoma of the Salivary Gland and the Diagnostic Utility of Giemsa Staining.

Secretory carcinoma is a salivary gland neoplasm first described as a mammary analogue secretory carcinoma by Skalova and redesignated as a secretory carcinoma in the 2017 World Health Organization Classification of Head and Neck Tumors. Secretory carcinoma diagnosis is reliant on specific cytological and histological findings and the detection of an ETV6-NTRK3 fusion gene. Here, we examined the clinical and cytopathological features of four cases of secretory carcinoma occurring in three males and a female, aged between 39 and 74 years. All four tumors involved the parotid gland, and were found to have the ETV6-NTRK3 fusion gene. Fine-needle aspiration-based cytology smears of all tumors displayed papillary and/or dendritic pattern clusters, some of which were associated with blood vessels. The neoplastic cells displayed enlarged nuclei with fine chromatin and small, distinct, single nucleoli. Furthermore, several neoplastic cells with a characteristic vacuolated cytoplasm were identified in each specimen. Giemsa staining revealed cytoplasmic vacuolation, intracytoplasmic metachromatic secretions and/or various sized metachromatic granules, and a background of metachromatic mucin in all four specimens. Given this, we conclude that these cytological findings, especially those of the Giemsa staining, might be helpful in the diagnosis of secretory carcinoma.

Clinical and Pathological Characteristics of Hyaline-Vascular Type Unicentric Castleman Disease: A 20-Year Retrospective Analysis.

The first case of hyaline vascular type of unicentric Castleman disease (HV-UCD) was reported more than six decades ago. Since patients with HV-UCD are often asymptomatic and this condition is generally discovered incidentally on imaging tests, most of the previous reports were of mediastinal origin detected by chest radiography. In recent years, improved access to imaging modalities has provided new insights in the diagnosis of this condition. In this study, we reviewed the detailed clinical and pathological findings of 38 HV-UCD cases (20 males and 18 females, mean age: 42.8 years). The most common site involved was the abdominal cavity (34.2%), followed by mediastinum (23.7%) and retroperitoneum (15.8%). In the abdominal cavity, mesenteric origin was the most common. The mean size of masses was 4.8 cm. Pathologically, thick hyalinized collagen fibers surrounding large blood vessels and calcification were observed (81.6% and 23.7%, respectively). Multinucleated giant cells resembling Warthin-Finkeldey cell were also observed in occasional cases (23.7%). This is a unique paper that summarizes detailed clinical and pathological findings of a large series of a rare disease. The clinical information presented in this paper is more plausible than previous views and is useful for accurate diagnosis and understanding of the disease.

Primary Gastrointestinal T-Cell Lymphoma and Indolent Lymphoproliferative Disorders: Practical Diagnostic and Treatment Approaches.

Primary gastrointestinal (GI) T-cell neoplasms are extremely rare heterogeneous disease entities with distinct clinicopathologic features. Given the different prognoses of various disease subtypes, clinicians and pathologists must be aware of the key characteristics of these neoplasms, despite their rarity. The two most common aggressive primary GI T-cell lymphomas are enteropathy-associated T-cell lymphoma and monomorphic epitheliotropic intestinal T-cell lymphoma. In addition, extranodal natural killer (NK)/T-cell lymphoma of the nasal type and anaplastic large cell lymphoma may also occur in the GI tract or involve it secondarily. In the revised 4th World Health Organization classification, indolent T-cell lymphoproliferative disorder of the GI tract has been incorporated as a provisional entity. In this review, we summarize up-to-date clinicopathological features of these disease entities, including the molecular characteristics of primary GI T-cell lymphomas and indolent lymphoproliferative disorders. We focus on the latest treatment approaches, which have not been summarized in existing reviews. Further, we provide a comprehensive review of available literature to address the following questions: How can pathologists discriminate subtypes with different clinical prognoses? How can primary GI neoplasms be distinguished from secondary involvement? How can these neoplasms be distinguished from non-specific inflammatory changes at an early stage?