World Health Organization classification of thymomas provides significant prognostic information for selected stage III patients: evidence from an international thymoma study group

Thymoma type B2 progression, due to fear of contamination, in association with hydrocephalus: A case report of avoidant behavior during COVID-19 pandemic

The novel coronavirus pandemic outbreak caused extreme public fear, health concerns, and psychological distress, especially in oncology patients. The presented rare case is of a 40-year-old female with thymoma type B, with rapid progression, due to fear from the COVID-19 pandemic. Biopsy and histological verification of the tumor show a B-type thymoma with a high proliferative index. The fear of infection is causing avoidant behavior and leads to suboptimal therapy in some oncology patients that will have severe consequences. We can conclude that adequate, personalized, and most importantly, active psychological care is necessary and should be implemented for cancer patients. To be prepared for a future lockdown, it may be helpful to urge patients to seek alternative forms of social contact, such as online and mobile communications, to combat depression lockdown effects.

Juan Rosai as master of our comprehensive understanding of thymus and thymoma

In this study, the authors report on the activity of Juan Rosai, one of the pathologists most engaged in the definition of cells, diseases and tumors occurring in the thymus and in the mediastinum during the last 60 years. With his morphological skills and tireless interest in clarification of disease patterns, he contributed extraordinarily to expand our knowledge of the mediastinal diseases and to improve our diagnostic approach. He determined extraordinary advances also in trasmission electron microscopy and in immunohistochemistry as powerful diagnostic tools. Moreover, he proposed and promoted, together with an international panel of Pathologists, the World Health Classification of Thymic tumors as a definite progress in our comprehension and diagnostics of thymic epithelial tumors (TET). Our purpose is to review J. Rosai's achievements in thymic normal structure, in TET and particularly in the entity now definied as "thymoma", in distinction from the thymic carcinoma. To do this, our narrative will also be based on personal memories, longstanding collaborations and/or friendship with J. Rosai.

Histotyping of Indian thymomas: A clinicopathologic study from north India

Background & objectives:

Thymomas are rare, but most common anterior mediastinal lesions. The histomorphologic spectrum of thymic epithelial tumours (TETs) in Indian population has not been explored in depth. This study was aimed to assess the histomorphology of TETs in the Indian patients and correlate clinical parameters with pathological features.

Methods:

It was a retrospective study conducted in a tertiary referral hospital in north India. All morphologically confirmed cases of TETs since 2009 were included. Clinical details and histology slides were reviewed using the Modified Masaoka-Koga staging system and WHO 2015 classification. Clinicopathological correlation and survival analysis were done. A comparative review from other published Indian studies was performed.

Results:

A total of 219 cases of TETs (138 resections and 81 biopsies) were identified. The most common histomorphologic type was B2, and the most frequent stage was I. Types A/AB were common in older age (P<0.01). Clinically, higher stage tumours were found mostly in men (P<0.01), and these were Type B thymomas (P<0.01). Myasthenia gravis was more common in women (P<0.02) and in lower stages (P<0.05). Survival analysis revealed significant association between recurrence and tumour stage. Although thymic carcinoma was diagnosed on biopsy, no resectable case was identified.

Interpretation & conclusions:

Our findings showed that the thymomas in Indian patients were most commonly Stage I tumours of B2 and AB histotypes. Resected thymic carcinomas were conspicuously absent in our study. More studies need to be done to establish the frequency and biology of TETs from India.

Inter-relationship among myasthenia gravis, WHO histology, and Masaoka clinical stage and effect on surgical methods in patients with thymoma: a retrospective cohort study

Background

The aim of study is to analyze the inter-relationship among WHO histology, myasthenia gravis (MG) and Masaoka stage and to assess the feasibility of thoracoscopic surgery in thymoma patients.

Methods

Data from 142 consecutive thymoma patients from January 2009 to March 2016 were retrospectively reviewed in our institution. Histological classification and clinical staging were assessed by WHO histology criteria and Masaoka stage. We investigated the clinical characteristics, inter-relationship among WHO histology, MG and Masaoka stage, and compared the feasibility and safety of thoracoscopic thymectomy by comparison of open thymectomy.

Results

Among 142 patients, the incidence of MG was 29.6%. Compared with A and AB-type thymomas, a higher prevalence of advance clinical stage was in B1 to C-type thymomas (37/63 vs. 9/43, P<0.001), and there was an increased trend of Masaoka stage from A to C-type thymomas (P<0.001). The incidence of MG was significantly higher in AB, B1 and B2-type thymomas than other type thymomas (23/63 vs. 6/44, P=0.009) and in early Masaoka clinical stage than advanced Masaoka clinical stage (29/80 vs. 12/59, P=0.042). Thoracoscopic surgery could significantly decrease blood loss in patients with (104.06±137.36 vs. 350.91±560.79 mL, P=0.001) or without MG (91.90±77.70 vs. 266.32±292.60 mL, P=0.02), with comparable complications. Additionally, thoracoscopic surgery could achieve an equal effect on the remission of MG with open surgery (7/11 vs. 10/14, P=1.000), and Masaoka stage was significantly associated with the remission of MG after thymectomy.

Conclusions

Our study suggests that WHO histology, MG, and Masaoka stage interrelate with one another, and Masaoka stage is an important prognostic factor in remission of MG after thymectomy in thymoma patients. Thoracoscopic thymectomy could achieve an equal efficacy to open thymectomy and should be recommended as a routine surgery for patients with early Masaoka stage.

Metastatic type A thymoma: morphological and genetic correlation

AIMS

The vast majority of type A thymomas are diagnosed in tumour stages 1 or 2, and metastatic cases are exceedingly rare. The histological and genetic features of such metastatic type A thymomas have not been described in detail.

METHODS AND RESULTS

Five metastatic type A thymomas in tumour stage Masaoka IVb that had been reviewed by a panel of expert pathologists were analysed using comparative genomic hybridization (CGH). Cases 1, 2 and 3 showed the prototypical morphology of type A thymomas with mainly solid growth patterns. These cases displayed only very subtle nuclear irregularities and slight nuclear crowding, but no other atypical features. Mitoses were absent. Cases 3 and 4, in contrast, had a distinctly atypical morphology. CGH revealed partially recurrent alterations in four cases (with and without atypical morphology), including gains on chromosome 1q (one case), 17q (two cases), chromosome 19 (three cases) and 22q (one case) and losses on chromosome 17p (two cases) and 22q (one case).

CONCLUSION

Rare metastatic type A thymomas, both with typical and 'atypical' histological features, show partially recurrent genomic alterations that differ from the much more frequent localized and indolent tumours. The fact that these alterations were recurring points to a link between clinical behaviour and molecular features. Our findings may have implications for the management and treatment of such tumours.

Case Report of Thymoma Tumor Reduction Following Plasmapheresis

For thymoma, multidisciplinary antitumor strategy is composed of surgery, chemotherapy, and radiotherapy. Meanwhile, ~20% to 25% of patients with thymoma have myasthenia gravis and plasmapheresis is recommended for thymoma-associated myasthenia gravis.We report a case that a 40-year-old woman with thymoma experiencing tumor relapse after surgery showed significant response to plasmapheresis.This is the first case of thymoma responded to plasmapheresis, which may guide the study of the etiology and pathogenesis of thymoma.

Evidence-based pathology: systematic literature reviews as the basis for guidelines and best practices

CONTEXT

Evidence-based medicine has been proposed as a new paradigm for the identification and evaluation of medical information. Best available evidence or data are identified and used as the basis for the diagnosis and treatment of individual patients. Evidence-based pathology has adapted basic evidence-based medicine concepts to the specific needs of pathology and laboratory medicine.

OBJECTIVES

To briefly review the history and basic concepts of evidence-based medicine and evidence-based pathology, describe how to perform and interpret systematic reviews, and discuss how to integrate best evidence into guidelines.

DATA SOURCES

PubMed (National Library of Medicine, Washington, DC) and Web of Science (Thompson Reuters, New York, New York) were used.

CONCLUSIONS

Evidence-based pathology provides methodology to evaluate the quality of information published in pathology journals and apply it to the diagnosis of tissue samples and other tests from individual patients. Information is gathered through the use of systematic reviews, using a method that is less biased and more comprehensive than ad hoc literature searches. Published data are classified into evidence levels to provide readers with a quick impression about the quality and probable clinical validity of available information. Best available evidence is combined with personal experience for the formulation of evidence-based, rather than opinion-based, guidelines that address specific practice needs.

Treatment and prognosis of type B2 thymoma

BACKGROUND

Because of the rarity of thymoma, no randomized trials have prospectively detected the prognosis and optimal treatment for type B2 thymoma. The aim of this study is to investigate the treatment and prognosis for patients with type B2 thymoma.

METHODS

We retrospectively evaluated the outcome of 42 patients with type B2 thymoma who were treated between 1995 and 2010 in Zhejiang Cancer Hospital. Survival curves were plotted using the Kaplan-Meier method. The Cox proportional hazard model was used for multivariate analysis.

RESULTS

The current study included 42 patients. The 5-year disease-free survival and overall survival rates were 62.8% and 84.9%, respectively. There were significant differences in disease-free survival and overall survival among different Masaoka stages (both P<0.001). Univariate and multivariate analysis revealed that Masaoka stage was associated with disease-free survival and overall survival (P=0.00 and 0.001, respectively).

CONCLUSIONS

Our results indicate that Masaoka stage affects disease-free survival and overall survival of patients with type B2 thymoma.

Identification of novel mutations of TP53, ALK and RET gene in metastatic thymic squamous cell carcinoma and its therapeutic implication

Thymic tumors are epithelial tumors of the thymus for which multimodal therapies are often ineffective because of a lack of standardized regimens. Due to the low incidence, the molecular pathology and genomic abnormalities of thymic epithelial tumors are largely unknown. In this study, we report our comprehensively genomic study on a case of metastatic thymic tumor. Using next generation deep DNA sequencing technology, we sequenced 190 segments of 46 cancer genes of the cancer genome to cover 739 COSMIC mutations in 604 loci. Among these sequenced cancer genes, we identified that three low frequency (~10% of cells) mutations in the TP53 gene (c.782+1G>T), ALK gene (c.3551C>T), and RET gene (c.2651A>T). To the best of our knowledge, this is the first study to show those mutations in thymic tumor. Of note, our study further indicates comprehensive molecular analysis may facilitate development of novel diagnostic and therapeutic strategies for thymic tumors.

STAT3 expression correlates with prognosis of thymic epithelial tumors

BACKGROUND

More and more evidences demonstrate the significance of Signal transducers and activators of transcription 3(STAT3) in oncogenesis and tumor development. However, little systematic researches have been reported on the correlation between STAT3 and thymic epithelial tumor (TET).

METHODS

Expression of STAT3 protein in 80 thymic epithelial tumors was detected by immunohistochemistry (IHC). The difference of STAT3 expression was compared by the χ(2) test. Estimation of survival was calculated using the Kaplan-Meier method, and the statistical differences were analyzed using the Log-rank test.

RESULTS

Positive expression of STAT3 protein was significantly associated with Masaoka staging and WHO histological classification (P<0.05), but not with age, gender, or tumor size. The rate of postoperative recurrence/metastasis was 33.33% in STAT3-positive tumors, compared with 4.55% in negative ones (P<0.05). 5-year survival was significantly lower in STAT3-positive subjects (61.11%) than in negative ones (97.73%) (P<0.01); In patients in Masaoka stage III or IV and WHO B3 or C, 5-year survival rate of subjects positive in STAT3 (35.00%, 35.00%) was statistically lower than that of the negative ones (92.31%, 91.67%). Cox regression analysis revealed that positive expression of STAT3 protein was an independent prognostic factor of thymic epithelial tumors (HR=9.325, P=0.044).

CONCLUSION

Positive expression of STAT3 protein increases along with the rising malignant degree of thymic epithelial tumors. It may be considered as an independent prognostic parameter with good prognostic value to evaluate the possibility of recurrence/metastasis in patients with thymic epithelial tumor.

Metaplastic thymoma of the mediastinum. A clinicopathologic, immunohistochemical, and genetic analysis

Metaplastic thymoma is a rare primary thymic epithelial tumor, and its biologic behavior is uncertain. We report 7 cases of metaplastic thymoma. The spindle components of the tumor seemed to be undergoing epithelial-mesenchymal transition, which is characterized by the loss of E-cadherin expression. Epstein-Barr virus seemed not to have an etiologic role in metaplastic thymoma. No gross genetic alterations were found by using comparative genomic hybridization. The patients were alive and well in follow-up ranging from 11 to 172 months (mean, 81.7 months). The findings suggest that metaplastic thymoma has a benign clinical course. Unless the histomorphologic findings show malignant features, surgical excision alone is recommended.

Evidence-Based Principles in Pathology: Existing Problem Areas and the Development of “Quality” Practice Patterns

Context.—Contrary to the intuitive impressions of many pathologists, several areas exist in laboratory medicine where evidence-based medicine (EBM) principles are not applied. These include aspects of both anatomic and clinical pathology. Some non-EBM practices are perpetuated by clinical “consumers” of laboratory services because of inadequate education, habit, or overreliance on empirical factors. Other faulty procedures are driven by pathologists themselves.

Objectives.—To consider (1) several selected problem areas representing non-EBM practices in laboratory medicine; such examples include ideas and techniques that concern metastatic malignancies, “targeted” oncologic therapy, general laboratory testing and data utilization, evaluation of selected coagulation defects, administration of blood products, and analysis of hepatic iron-overload syndromes; and (2) EBM principles as methods for remediation of deficiencies in hospital pathology, and implements for the construction of “quality” practices in our specialty.

Data Sources.—Current English literature relating to evidence-based principles in pathology and laboratory medicine, as well as the authors' experience.

Conclusions.—Evidence-based medicine holds the promise of optimizing laboratory services to produce “quality” practices in pathology. It will also be a key to restraining the overall cost of health care.