Advances in thymic carcinoma diagnosis and treatment: a review of literature

Machine learning-based radiomic computed tomography phenotyping of thymic epithelial tumors: Predicting pathological and survival outcomes

OBJECTIVE

For patients with thymic epithelial tumors, accurately predicting clinicopathological outcomes remains challenging. We aimed to investigate the performance of machine learning-based radiomic computed tomography phenotyping for predicting pathological (World Health Organization [WHO] type and TNM stage) and survival outcomes (overall and progression-free survival) in patients with thymic epithelial tumors.

METHODS

This retrospective study included patients with thymic epithelial tumors between January 2001 and January 2022. The radiomic features were extracted from preoperative unenhanced computed tomography images. After strict feature selection, random forest and random survival forest models were fitted to predict pathological and survival outcomes, respectively. The model performance was assessed by the area under the curve (AUC) and validated internally by the bootstrap method.

RESULTS

In total, 124 patients with a median age of 61 years were included. The radiomics random forest models of WHO type and TNM stage showed satisfactory performance with an AUC_WHO of 0.898 (95% CI, 0.753-1.000) and an AUC_TNM of 0.766 (95% CI, 0.642-0.886). For overall survival and progression-free survival prediction, the radiomics random survival forest models showed good performance (integrated AUCs, 0.923; 95% CI, 0.691-1.000 and 0.702; 95% CI, 0.513-0.875, respectively), and the integrated AUCs increased to 0.935 (95% CI, 0.705-1.000) and 0.811 (95% CI, 0.647-0.942), respectively, when combined with clinicopathological features.

CONCLUSIONS

Machine learning-based radiomic computed tomography phenotyping might allow for the satisfactory prediction of pathological and survival outcomes and further improve prognostic performance when integrated with clinicopathological features in patients with thymic epithelial tumors.

Does Myasthenia Gravis Affect Long-Term Survival in Thymic Carcinomas? An ESTS Database Analysis

Background: Thymic carcinoma is a rare and highly malignant tumor with a dismal prognosis, which occasionally coexists with myasthenia gravis (MG). This study aims to investigate the MG incidence on a surgical cohort of patients with thymic carcinoma and to explore its influence on long-term survival. Methods: the prospectively collected data from the ESTS database on thymic epithelial tumors were reviewed. Clinical, pathological, and survival information on thymic carcinoma were analyzed. Results: the analysis was conducted on 203 patients, with an equal gender distribution (96 males and 107 females). MG was detected in 22 (10.8%) patients, more frequently elderly (>60 years, p = 0.048) and male (p = 0.003). Induction therapy was performed in 22 (10.8%) cases. After surgery, 120 (59.1%) patients had a Masaoka stage II−III while complete resection (R0) was achieved in 158 (77.8%). Adjuvant therapy was performed in 68 cases. Mean follow-up was 60 (SD = 14) months. The 3-year, 5-year and 10-year survival rates were 79%, 75% and 63%, respectively. MG did not seem to influence long-term survival (5-year survival in non-MG−TCs 78% vs. 50% in MG−TCs, p = ns) as age < 60 years, female gender, early Masaoka stage, and postoperative radiotherapy did, conversely. Conclusions: myasthenia occurred in about 10% of thymic carcinomas and it did not seem to affect significantly the long-term prognosis in surgically treated thymic carcinoma-patients.

Myasthenia Gravis Related to Thymic Carcinoma: A Case Study

Myasthenia gravis and thymoma are often presented in association with ∼10% of myasthenic cases having concomitant thymoma. Thymic carcinoma is one of the rarest/aggressive human epithelial tumors and has no correlation with myasthenia gravis hitherto. Here is provided a clinical case and review of literature on a very rare association of thymic carcinoma (with no sign of thymoma) and myasthenia gravis (antiacetylcholine receptor antibody positive). Two years after thymectomy, clinical evolution was satisfactory. This clinical case elicits hypothesis that thymic carcinoma may be related with myasthenia gravis, what may have good prognostic from oncologic and neurologic perspectives.

Utility of Cluster of Differentiation 5 and Cluster of Differentiation 117 Immunoprofile in Distinguishing Thymic Carcinoma from Pulmonary Squamous Cell Carcinoma: A Study on 1800 Nonsmall Cell Lung Cancer Cases

Background

Mediastinum harbors a mixed bag of neoplastic lesions with varied therapeutic and prognostic implications. Distinguishing pulmonary squamous cell carcinoma from thymic carcinoma is a challenging task owing to rather nonspecific clinicoradiological features and a considerable overlap in histomorphological features. Thus, we evaluated the diagnostic utility of cluster of differentiation 5 (CD5) and CD117 immunohistochemical markers in distinguishing these tumors.

Materials and Methods

The archives of department of histopathology were retrospectively reviewed from June 2012 to May 2016. Formalin-fixed paraffin-embedded blocks of 1800 cases diagnosed as nonsmall cell lung carcinoma were retrieved, and immunohistochemical expression of CD5 and CD117 was evaluated in these cases.

Results

Adenocarcinoma (980; 54.44%) was the most common histological subtype of lung carcinoma observed in our study. CD117 was positive in 171 out of 1800 cases (9.5%) of which 120 cases (70.17%) were adenocarcinoma, followed by 40 cases (23.4%) of squamous cell carcinoma. Immunoreactivity for CD5 was observed in 209 cases (11.61%), 200 (95.7%) cases of which were diagnosed as adenocarcinoma. None of the cases diagnosed as squamous cell carcinoma on histomorphology showed CD5 immunoexpression.

Conclusion

While thymic squamous cell carcinomas are well known for CD5 and CD117 coexpression, none of the cases of squamous cell carcinoma arising in lung express CD5. These markers are a diagnostic tool to distinguish a primary lung squamous cell carcinoma from thymic carcinoma, particularly in the setting of a central pulmonary lesion with mediastinal involvement.

Imaging Evaluation of Mediastinal Masses in Children and Adults: Practical Diagnostic Approach Based on A New Classification System

A compartmental approach to the diagnosis of the mediastinal masses in children and adults has been widely used to facilitate the diagnosis and planning of diagnostic interventions and surgical treatment for many years. Recently, a new computed tomography-based mediastinal division scheme, approved by the International Thymic Malignancy Interest Group, has received considerable attention as a potential new standard. In this review article, this new computed tomography-based mediastinal division scheme is described and illustrated. In addition, currently used imaging modalities and techniques, practical imaging algorithm of evaluating mediastinal masses, and characteristic imaging findings of various mediastinal masses that occur in children and adults are discussed. Such up-to-date knowledge has the potential to facilitate better understanding of mediastinal masses in both pediatric and adult populations.

Differential diagnostic value of CD5 and CD117 expression in thoracic tumors: a large scale study of 1465 non-small cell lung cancer cases

Background

Thoracic pathologists are frequently faced with tissue specimens from intrathoracic/mediastinal tumors. Specifically the differentiation between thymic and pulmonary squamous cell carcinomas (SqCC) can be challenging. In order to clarify the differential diagnostic value of CD5 and CD117 in this setting, we performed a large scale expression study of both markers in 1465 non-small cell lung cancer (NSCLC) cases.

Methods

Tissue microarrays of formalin-fixed paraffin-embedded resection specimens of 1465 NSCLC were stained with antibodies against CD117 and CD5. Positivity of both markers was correlated with clinicopathological variables.

Results

CD117 was positive in 145 out of 1457 evaluable cases (9.9 %) and CD5 was positive in 133 out of 1427 evaluable cases (9.3 %). 28 cases (1.9 %) showed coexpression of CD117 and CD5. Among the 145 cases that were positive for CD117, 97 (66.8 %) were adenocarcinomas (ADC), 34 (23.4 %) were SqCC, 5 (3.4 %) were adenosquamous carcinomas (ADSqCC), 8 (5.5 %) were large cell carcinomas (LC), and one (0.6 %) was a pleomorphic carcinoma (PC). In the CD5 positive group consisting of 133 cases, 123 (92.4 %) were ADC, 0 (0 %) were SqCC, 4 (3.0 %) were ADSqCC, 3 (2.2 %) LC and 3 (2.2 %) were PC. None of the 586 SqCC showed expression of CD5. No association of CD117- or CD5 positivity to patients’ age, pathological stages or to T-, N-, or M- categories was observed.

Conclusions

A substantial subset of NSCLC exhibit positivity of CD117 and CD5. Since CD5 expression was not observed in pulmonary SqCC, but is expressed in the majority of thymic squamous cell carcinomas, the application of this immunomarker is a valuable tool in the differential diagnosis of thoracic neoplasms.

Electronic supplementary material

The online version of this article (doi:10.1186/s13000-015-0441-7) contains supplementary material, which is available to authorized users.

Pathologic Finding of Thymic Carcinoma Accompanied by Myasthenia Gravis

Background and Purpose

The World Health Organization (WHO) has classified thymic carcinoma and other thymomas (types A, AB, and B) as different neoplasms. Myasthenia gravis (MG) is an early sign of thymoma and theoretically does not accompany thymic carcinoma; however, cases of thymic carcinoma with MG have been reported. Whether thymic carcinoma can accompany MG has yet to be established.

Methods

The medical records of patients who underwent thymectomy for MG between 1990 and 2011 in a single hospital were reviewed. All cases with the diagnostic code of "thymic carcinoma" or "thymoma type C" (old terminology) were selected. A pathologist re-reviewed the pathologic specimens using the new WHO criteria. The rate of thymic carcinoma among these MG patients was then calculated.

Results

A total of 81 patients with MG had thymic tumors, 10 of whom had thymic carcinomas or thymoma type C. Seven cases of well-differentiated thymic carcinomas (type B3) were excluded, leaving three (3.7%) cases of thymic carcinoma with MG. All three of these cases were type B3 thymoma with a focal squamous cell carcinoma component that was very small and well demarcated. In addition, two out of the three tumors were found to be at an early clinical stage. All of the cases survived without recurrence over follow-up periods of at least 5 years.

Conclusions

Thymic carcinoma transformation from thymoma can occur during the early stages of thymoma. The association of this condition with MG is not as rare as was previously thought. Thymic carcinomas accompanying MG had a predominant B3 thymoma component with a focal thymic carcinoma area (squamous cell carcinoma).

Docetaxel for platinum-refractory advanced thymic carcinoma

OBJECTIVE

Thymic carcinoma is a rare mediastinal neoplasm. While platinum-based chemotherapy has been reported to be effective for advanced thymic carcinoma in a first-line setting, little information is available regarding the benefits of salvage chemotherapy for platinum-refractory thymic carcinoma. This study assessed the efficacy and safety profiles of docetaxel monotherapy for platinum-refractory thymic carcinoma.

METHODS

A total of 13 thymic carcinoma patients treated with docetaxel monotherapy in a second- or later-line setting between January 2003 and April 2014 were retrospectively reviewed. The median age was 61 years (range, 41-75 years).

RESULTS

The overall response rate and disease control rate were 31% [95% confidence interval (CI), 6-56%] and 77% (95% CI, 54-100%), respectively. The median progression-free survival and overall survival after docetaxel monotherapy were 5.5 months (95% CI, 2.3-6.5 months) and 24.0 months (95% CI, 9.4-31.2 months), respectively. The most common Grade ≥3 toxicity was neutropenia (62%). No incidents of febrile neutropenia and no treatment-related deaths were recorded.

CONCLUSIONS

This retrospective analysis demonstrated that docetaxel was active against platinum-refractory thymic carcinoma with acceptable toxicities. Docetaxel monotherapy might be a promising therapeutic option for patients with platinum-refractory thymic carcinoma.

A rare case of primary thymic adenocarcinoma mimicking small cell lung cancer

Primary thymic adenocarcinoma is a very rare malignancy of the anterior mediastinum with no standardized treatment. A 36-year-old male patient presented with hoarseness over the past 3 months. A chest computed tomography (CT) scan showed an infiltrative mass to the proximal vessels and aortic arch in left upper mediastinum (4.1×3.1×5.4 cm). Brain magnetic resonance imaging (MRI) showed focal lesions, suggesting metastasis in the left frontal lobe. A thoracoscopic biopsy of the mediastinal mass confirmed a primary thymic adenocarcinoma forming a glandular structure with atypia of tumor cells. The patient received four cycles of systemic chemotherapy, consisting of etoposide and cisplatin, with concurrent radiotherapy (6,000 cGy/30 fractions) to the mediastinal lesion and the metastatic brain lesion (4,200 cGy/12 fractions). A follow-up chest CT scan and brain MRI showed a decrease in the size of the left upper mediastinal mass and brain lesion. We report a rare case of the primary thymic adenocarcinoma with a literature review.