Carcinoma showing thymic-like elements--a rare malignancy of the thyroid gland

Thyroid Malignancies With Thymic Differentiation: Outcomes of Rare SETTLE and CASTLE Tumors

BACKGROUND

Spindle epithelial tumors with thymus-like differentiation (SETTLE) and carcinomas showing thymus-like differentiation (CASTLE) are rare intrathyroid tumors.

METHODS

This retrospective cohort study included patients diagnosed with SETTLE, CASTLE, and papillary thyroid carcinoma (PTC) from 2004 to 2020 within the National Cancer Database (NCDB). Demographic, tumor, and treatment characteristics were compared. Overall survival (OS) was analyzed using the Kaplan-Meier method and Cox regression models.

RESULTS

This study identified 19 patients with CASTLE, 11 with SETTLE, and 483 474 with PTC. CASTLE and SETTLE patients had larger tumors, lymphovascular invasion, and positive surgical margins. They were rarely treated with radioactive iodine treatment but frequently received external beam radiation and chemotherapy. Five-year OS was significantly lower for CASTLE and SETTLE compared to PTC. SETTLE was associated with an increased risk of death.

CONCLUSION

SETTLE and CASTLE are rare intrathyroid tumors with worse survival compared to PTC, often managed with radiation, chemotherapy, and surgery.

Neuroendocrine neoplasms of head and neck, genitourinary and gynaecological systems, unknown primaries, parathyroid carcinomas and intrathyroid thymic neoplasms: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up

•This Clinical Practice Guideline provides key recommendations for managing rare endocrine tumours. •Neuroendocrine neoplasms of different origins, parathyroid carcinoma and intrathyroid thymic neoplasms are included. •The guideline covers clinical imaging and pathological diagnosis, staging and risk assessment, treatment and follow-up. •The authors comprise a multidisciplinary group of experts from different institutions and countries in Europe. •Recommendations are based on available scientific data and the authors’ collective expert opinion.

Intra thyroid thymic carcinoma: A case report and literature review

INTRODUCTION AND IMPORTANCE

Intrathyroid thymic carcinoma (ITC) is a malignant epithelial tumor with thymic differentiation within the thyroid gland. Its frequency is up to 0.15 % of all malignant thyroid tumors. It is frequently a low-grade tumor. The clinical status is often misleading to other more advanced tumors like cervical lymph node metastasis of nonkeratinizing squamous cell carcinoma, undifferentiated variant, dedifferentiated carcinoma, and medullary carcinoma of the thyroid.

CASE PREPARATION

The patient came to us with the diagnosis of cervical lymph node metastasis of undifferentiated carcinoma. This patient was first diagnosed with cervical lymph node metastasis in the previous hospital. After having an ITC diagnosis, the patient was operated on the rennet of thyroid glands and had a low dose of radio-chemotherapy for recurrent prevention purposes. It is the first case of such a disease diagnosed at our hospital and also the first case reported in Vietnam.

CLINICAL DISCUSSION

ITC is rare and appears similar to all thymic carcinoma variants. The most popular type is squamous carcinoma. Immunohistochemical stains are typical for thymic origin tumors with CD5, CD117 positive. ITC is often negative for monoclonal PAX8 but positive in this case (MRQ-50 clone, Sigma-Aldrich). This finding is an exciting one that should considered.

CONCLUSION

Reporting the case increases the awareness of the disease, especially among Vietnam Doctors and patients.

Case report: Thymoid differentiated carcinoma of thyroid: Two cases

Objective

Thymoid carcinoma of the thyroid gland is a rare thyroid tumor, which is often presented in case reports.

Methods

The clinical data of two patients with thymic carcinoma of the thyroid gland were retrospectively reviewed.

Results

Case 1: a middle-aged woman who was admitted to the hospital because of "progressive enlargement of the anterior cervical mass for 8 months." Color Doppler ultrasound and CT showed malignant tumor with high possibility of bilateral cervical lymph node metastasis. Total thyroidectomy and bilateral central cervical lymph node dissection were performed. Lymph node biopsy showed the metastasis of small cell undifferentiated thyroid carcinoma. Because the biopsy pathological result was not consistent with the pathology of the primary lesion, immunohistochemistry was performed again, and the final diagnosis was thymic carcinoma in the thyroid gland. Case 2: the patient was an elderly man who was admitted to the hospital due to hoarseness for half a month. During the operation, the tumor invaded the trachea, esophagus, internal jugular vein, common carotid artery, and surrounding tissues. Palliative resection of the tumor was performed. The tumor postoperative pathology suggested thymoid carcinoma of the thyroid gland. It recurred and compressed the trachea 4 months after the operation, resulting in dyspnea of the patient, and finally tracheotomy was performed to alleviate the symptoms.

Conclusion

Case 1 showed multiple differences in pathological diagnosis, suggesting that the lack of specific imaging and clinical manifestations of thymoid-differentiated thyroid carcinoma made the diagnosis so difficult. Case 2 progressed rapidly, suggesting that thymoid-differentiated thyroid carcinoma was not always inert, and the treatment and follow-up should follow the principle of individualization.

Thyroid Carcinoma Showing Thymus-like Differentiation (CASTLE): A Case Report

Background and Objectives: Carcinoma showing thymus-like differentiation (CASTLE) is a low-grade thyroid carcinoma, with an indolent clinical course and usually a favorable prognosis. The clinical and imagistic features are not specific for CASTLE but similar to other malignant lesions of the thyroid. Definite diagnosis is based on an immunohistochemical examination, as this carcinoma shows positive CD5 immunoreactivity when compared to other aggressive thyroid carcinomas. Case presentation: The main focus of this study is to outline a rare case of CASTLE compressing the trachea in a 50-year-old female patient who was initially diagnosed with undifferentiated thyroid carcinoma, for which she underwent unsuccessful surgery, as well as postoperative radiotherapy and chemotherapy. After receiving a second medical opinion, the patient underwent a challenging radical resection consisting in total thyroidectomy and central neck dissection, with no local recurrence after 6 months and 2 years of follow-up and negative metastatic follow-up. The correct diagnosis has been established based on pathological and immunohistochemical examinations. Conclusions: In summary, the diagnosis of CASTLE is difficult and requires an experienced histological analysis and CD5 immunoreactivity. Lack of metastasis, complete removal of the tumor, and a low degree of tumor infiltration into nearby structures are all associated with better long-term survival.

Recurrence of carcinoma showing thymus-like differentiation (CASTLE) involving the thyroid gland

BACKGROUND

Carcinoma showing thymus-like differentiation (CASTLE) in the thyroid gland is a rare disease with generally a favorable prognosis. Treatment with surgery and adjuvant radiotherapy has been shown to improve local control and long-term survival rates. In this report, we present a case of a recurrent thyroid gland CASTLE and review the literature on the diagnosis and treatment of this disease.

CASE PRESENTATION

A 60-year-old woman, who was diagnosed with a CASTLE thyroid tumor in 2015, had a total thyroidectomy and was maintained on thyroid hormone replacement (levothyroxine). After 5 years, the patient had a recurrence, in an advanced stage unsuitable for surgery. As the patient declined to undergo radiotherapy, she was followed up without intervention and is currently stable after 15 months.

CONCLUSIONS

CASTLE is a rare disease, diagnosed based on postoperative pathology and immunohistochemistry analysis, especially upon CD5 marker. In case of relapse, treatment options include surgery and radiotherapy; however conservative management without intervention is an acceptable alternative in some cases.

Inoperable CASTLE of the thyroid gland treated with radical radiotherapy with complete remission

Carcinoma showing thymus-like elements (CASTLE) is an extremely rare malignant tumor of the thyroid gland and soft tissues of the neck with favorable prognosis. Histological features of the CASTLE are similar to thymic carcinoma, and it is assumed that it arises from the ectopic thymic tissue or the remnants of branchial pouches. The optimal treatment strategy is still uncertain because of the rarity of the tumor. The mainstay of treatment is surgery. The role of other modalities is unclear. We present a case report of a patient with locally advanced CASTLE of the thyroid gland who was not suitable for surgery and underwent radical radiotherapy with subsequent achievement of complete remission. We also present a literature review.

Whole exome sequencing and establishment of an organoid culture of the carcinoma showing thymus-like differentiation (CASTLE) of the parotid gland

Carcinoma showing thymus-like differentiation (CASTLE) is a rare tumor, especially in the parotid gland. We encountered a CASTLE of the parotid gland and analyzed its clinicopathological features, as well as the genotype using whole exome sequencing (WES). Moreover, we successfully established an organoid culture cell line from the primary tumor tissue. The patient was a 23-year-old woman who underwent superficial parotidectomy with peripheral neck dissection, followed by radiotherapy. Pathologically, the resected specimen showed atypical epithelioid nests and trabeculae with squamous differentiation, separated by thick fibrous septa, accompanied by dense lymphocytes and plasma cell infiltration. Immunohistochemistry revealed that the tumor cells were positive for AE1/AE3, p40, p63, p16, CK5/6, and CD5, and the background lymphocytes were positive for CD5 and CD99. Based on these findings, the tumor was diagnosed as CASTLE. WES uncovered five nonsynonymous and splicing somatic mutations, namely, FREM2 p.Val861Phe, CLK3 p.Phe376Leu, DLGAP1 p.Lys294Asn, NOX1 p.Val165Met, and PSG9 c.430 + 4A > T. Organoid culture cells preserved the histopathological characteristics of the epithelioid component of CASTLE and harbored all five somatic mutations detected in the primary tumor. In conclusion, for the first time to the best of our knowledge, we successfully analyzed a comprehensive genotype and established an organoid culture cell line of a parotid gland CASTLE, which should serve for analyzing the nature of this rare tumor.

Identification of Recurrent TERT Promoter Mutations in Intrathyroid Thymic Carcinomas

Intrathyroid thymic carcinoma (ITTC) is a rare malignant neoplasm considered to be a eutopic thymic carcinoma (TC) arising ectopically in the thyroid. Histopathologically, ITTC resembles squamous cell carcinoma of the thymus with positive TC markers such as CD5 and c-KIT. Despite these similar histological findings, ITTC is clinically less aggressive than TC. In this study, we compared clinical, histological, and genetic characteristics of ITTCs and TCs. We collected 9 ITTCs and 8 TCs with their clinicopathological profiles. Immunohistochemistry for CD5, p63, CD117/c-KIT, Ki-67, p53, TTF-1, thyroglobulin, PAX8, EGFR, and PD-L1/CD274 plus in situ hybridization for EBER was performed. We further investigated mutation status of KIT, EGFR, BRAF, and TERT promoter using Sanger sequencing. In our study, ITTCs affected significantly younger patients than TCs. After a mean follow-up of 86 months, all patients with ITTC were alive, while two patients with TC had died. Immunohistochemistry showed ITTCs and TCs had a similar immunophenotype except for EGFR and p53. Genetic analysis did not identify KIT or BRAF mutations in any ITTCs or TCs. EGFR mutations were positive in 11% (1/9) of ITTCs and 25% (2/8) of TCs. Notably, TERT promoter C228T mutation was identified in 22% (2/9) of ITTCs but none of the TCs. There were no significant differences in age, tumor size, or sex between TERT-mutated and TERT-wild-type ITTCs. Collectively, ITTC and TC have similar histopathologic and immunophenotypic features but different clinical outcomes. Recurrent TERT promoter mutation may be a key event related to cancer progression in ITTCs and warrants further investigation.

Thyroid Carcinoma Showing Thymus-Like Differentiation (CASTLE) with Tracheal Invasion: A Case Report

Patient: Male, 49-year-old

Final Diagnosis: Thyroid carcinoma showing thymus-like differentiation (CASTLE)

Symptoms: Hoarseness

Medication: —

Clinical Procedure: Thyroidectomy

Specialty: Surgery

Management and Prognostic Factors for Thyroid Carcinoma Showing Thymus-Like Elements (CASTLE): A Case Series Study

Introduction: This study aims to identify the prognostic factors that influence therapeutic modalities for thyroid carcinoma showing thymus-like elements (CASTLE).

Materials and Methods: Reported studies with CASTLE patients published between 2004 and 2018 were retrieved from a cross-database literature search. Three patients treated in our institute were also included as one case series. Standardized data collection was performed; data pertaining to clinical stages, treatment regimens, and survival time were collected and statistically analyzed.

Results: Up to 26 case series of CASTLE were selected, including 51 males and 38 females with a median age of 48 years. Follow-up time ranged from 2 to 362 months and the median survival time was 158.03 months. Lymph node metastasis and tumor invasion of adjacent tissue both showed a significant negative effect on survival (p = 0.001 and 0.013, respectively). Radiotherapy significantly improved survival (p = 0.034), while neck dissection significantly prolonged survival only in patients with extrathyroidal extension (p = 0.043).

Conclusions: Extrathyroidal infiltration and nodal metastasis are important factors in cancer outcomes. Radiation therapy appears to be important for better outcomes in CASTLE patients, and neck dissection is recommended for patients with extrathyroidal extension.

[A Case of Carcinoma Showing Thymus-Like Differentiation (CASTLE) of the Thyroid]

The case presented herein was a 70-year-old woman who had no compliant, but had a mass in the lower part of the right lobe of the thyroid detected by ultrasound (US). The US image of the tumor, measuring 13 mm in diameter, showed a low and heterogeneous internal echo level with calcification and an irregular margin. The tumor appeared to extend to the adjacent sternothyroid muscle, and cervical lymph node swelling was detected in a computer tomography (CT) image, but no metastatic lesion was found by positron emission tomography (PET)-CT. In a fine needle aspiration cytology of the tumor, papillary thyroid carcinoma was suggested because of the atypical epithelial cells having some changes other than intranuclear inclusion bodies. A subtotal thyroidectomy and central neck lymph node dissection were performed. The excised tumor was histologically composed of irregular nests or sheets of atypical squamoid epithelial cells with some ductal structures that leached to the sternothyroid muscle and involved the right lower parathyroid gland. Carcinoma showing thymus-like differentiation (CASTLE) was diagnosed histopathologically and immunohistochemically with the following immunohistochemical results: Cluster of differentiation 5 (CD5) (+), tumor protein p63 (p63) (+), KIT proto-oncogene receptor tyrosine kinase (c-KIT(CD117)) (+), thyroglobulin (-), and thyroid transcription factor-1 (TTF-1) (-). CASTLE is a rare carcinoma of the thyroid that architecturally resembles thymic epithelial tumors. Many CASTLE patients have been misdiagnosed as other carcinomas, such as anaplastic carcinoma, poorly differentiated carcinoma or squamous cell carcinoma of the thyroid. Immunohistochemical examination, including CD5 played an important role in the final diagnosis of CASTLE, although the distinction from diagnosis as squamous cell carcinoma or mucoepidermoid carcinoma in Hematoxylin-Eosin staining was challenging in our case. Nodal metastasis and perithyroidal tumor extension of CASTLE can predict its worse prognosis. Thus, at least careful follow-up studies are mandatory in cases of CASTLE.

Outcome of Thyroid Carcinoma Showing Thymus-Like Differentiation in Patients Undergoing Radical Resection

BACKGROUND

Carcinoma showing thymus-like differentiation (CASTLE) is a rare malignant tumor of the thyroid. It is difficult to diagnose, and there is no universally recognized therapeutic regimen. This study aims to define the clinicopathological features and discuss the optimal management of CASTLE.

METHODS

We retrospectively analyzed six patients with CASTLE who accepted surgery at the First Hospital of China Medical University between January 2010 and December 2015.

RESULTS

The six patients (three women and three men) had median age of 53 years (range 47-61 years). All patients presented with a slow-growing, painless neck mass; three patients also had hoarseness. All tumors were located in middle-lower or lower lobe, and two tumors extended to the substernal region. All patients underwent radical surgery without postoperative radiotherapy or chemotherapy. Five patients had extrathyroidal extension and two had lymph node metastasis. All six tumors were positive for CD5 and negative for thyroglobulin (Tg) and thyroid transcription factor (TTF)-1. Median follow-up was 32 months (range 23-81 months). Lateral cervical lymph node metastasis occurred in one patient at 26 months after initial treatment.

CONCLUSIONS

CASTLE is a rare, aggressive malignant tumor of the thyroid. Ultrasound, computed tomography, and fine-needle aspiration biopsy may not be sufficient to establish the diagnosis preoperatively; pathological examination and immunohistochemistry, particularly positive CD5 staining, are necessary to establish the diagnosis. Patients with CASTLE can yield a favorable outcome after radical surgery.

Clinical outcome of intensity modulated radiotherapy for carcinoma showing thymus-like differentiation

PURPOSE

To evaluate the efficacy and toxicity of adjuvant intensity-modulated radiotherapy (IMRT) after surgery for carcinoma showing thymus-like differentiation (CASTLE).

METHODS

Between September 2008 and June 2015, 14 CASTLE patients were retrospectively enrolled. The clinical features, treatment procedure and clinical outcomes were reviewed. All patients received postoperative IMRT. The radiation doses ranged from 56Gy/28 fractions to 66Gy/33 fractions. Treatment-related toxicities were graded by National Cancer Institute Common Toxicity Criteria (NCI-CTC) version 3.0.

RESULTS

After a median follow-up period of 42 months, only one patient suffered local recurrence and distant metastasis. The most frequently seen acute toxicities were mucositis and dermatitis (grade 1-2). No grade 3-4 toxicities were observed.

CONCLUSIONS

Although based upon a small series of consecutively treated patients, our study showed that adjuvant IMRT provides satisfactory local-regional control for CASTLE, with acceptable toxicities. Further studies are still warranted to clarify our findings.

Docetaxel/cisplatin Therapy in Myasthenia Gravis with Hypertension/diabetes

Background

Therapeutic options for thymoma-associated myasthenia gravis (MG) patients complicated with hypertension and/or diabetes post thymectomy are often conventional steroids. As the prevalence of diabetes and hypertension globally increases, other therapeutic options for these patients are of great importance.

Material/methods

9 patients with thymoma-associated MG complicated with hypertension and/or diabetes after thymectomy were administered 75 mg/m2 of docetaxel and 70 mg/m2 of cisplatin on day 1. The treatment could be repeated at 3-week intervals, ranging from 1 to 4 cycles according to the status of the patients. Therapeutic efficacy and side effects were evaluated.

Results

2 patients were complicated with type 2 diabetes, 6 with hypertension, and 1 with both diabetes and hypertension. After docetaxel/cisplain therapy, the MG symptoms were markedly improved in all patients (2, complete remission; 3, basic remission; 3, marked improvement; 1, improvement). Acetylcholine receptor (AchR) antibody levels were decreased in 8 patients. Minor adverse effects were observed in 2 patients, 1 with Grade II gastrointestinal reaction, and the other with pulmonary infection.

Conclusion

Docetaxel plus cisplatin might be an effective therapeutic option for thymoma-associated MG patients complicated with hypertension /diabetes post thymectomy without worsening thymoma and hypertension / diabetes.

CASTLE Thyroid Tumor: A Case Report and Literature Review

Carcinoma showing thymus-like differentiation is a rare tumor of the thyroid gland, which is structurally similar to thymic tissue. Overall, it has a favorable prognosis. Radiotherapy has been shown to be an effective local treatment, but there have been reports of distant recurrence. It has been suggested that adding chemotherapy may decrease the risk of recurrence. Here, we present a case report of a patient with a large tumor and extrathyroidal extension. The patient was treated with surgery, radiotherapy, and cisplatin with acceptable toxicity. The patient is free of locally recurrent or distant disease at 3 years.

Targeting thyroid cancer with acid-triggered release of doxorubicin from silicon dioxide nanoparticles

Currently, therapy for thyroid cancer mainly involves surgery and radioiodine therapy. However, chemotherapy can be used in advanced and aggressive thyroid cancer that cannot be treated by other options. Nevertheless, a major obstacle to the successful treatment of thyroid cancer is the delivery of drugs to the thyroid gland. Here, we present an example of the construction of silicon dioxide nanoparticles with thyroid–stimulating-hormone receptor-targeting ligand that can specifically target the thyroid cancer. Doxorubicin nanoparticles can be triggered by acid to release the drug payload for cancer therapy. These nanoparticles shrink the tumor size in vivo with less toxic side effects. This research paves the way toward effective chemotherapy for thyroid cancer.

Therapeutic Potential of Docetaxel plus Cisplatin Chemotherapy for Myasthenia Gravis Patients with Metastatic Thymoma

The prognosis of myasthenia gravis (MG) in association with invasive or metastatic thymoma is usually worse, and therapeutic options are quite limited. Here, we retrospectively reported the therapeutic effect of docetaxel plus cisplatin (docetaxel/cisplatin) chemotherapy in 7 MG patients with metastatic thymoma. Previously, all patients underwent thymectomy at the first onset of thymoma. After the metastasis of thymoma, none of the patients received thymectomy due to unresectable conditions after surgeon's evaluation for great risk of myasthenic crisis (n = 5) or patients' refusal (n = 2). All patients received docetaxel (75 mg/m²) and cisplatin (70 mg/m²) on day 1 (d1) every 21 days, with the cycle ranging from 1 to 4. After docetaxel/cisplatin chemotherapy, one patient achieved partial response, and 6 with stable disease of the tumors. The clinical symptoms of MG were alleviated in all patients, 2 with complete remission and the other 5 with marked improvement. Myelosuppression was the major adverse event, occurring in 2 patients (grade II and IV). MG relapse occurred in one patient during the follow-up. Our study presented a series of MG patients with metastatic thymoma who underwent docetaxel/cisplatin chemotherapy. Besides the improved/stabilized thymoma, markedly improvement of MG with the tolerable adverse events was achieved. Docetaxel/cisplatin chemotherapy appears to be an effective treatment for selected patients with MG in association with unresectable metastatic thymoma. Further follow-up of these patients and additional subjects will be needed to determine whether the therapeutic benefits are durable.

Carcinoma Showing Thymus-Like Differentiation (CASTLE): Cytopathological Features and Differential Diagnosis

BACKGROUND

CASTLE (carcinoma showing thymus-like differentiation) is a rare tumor (accounting for less than 0.15% of thyroid neoplasms) with most of the reported cases from Asia. Although this tumor is rare, distinguishing it from more aggressive neoplasms is critical because of its improved prognosis. To date, there have been limited studies on its cytomorphological features. Herein, we review the cytomorphological features of 10 fine-needle aspiration (FNA) cases of histologically confirmed CASTLE and discuss the findings in light of the current literature.

METHODS

We retrospectively (1989-2016) identified 10 cases of CASTLE from 17,415 surgical cases of thyroid carcinoma from The Johns Hopkins Hospital and Fudan University Shanghai Cancer Center. The cases were reviewed for discrete cytomorphological characteristics.

RESULTS

All of the cases displayed predominantly single (dishesive) epithelial cell populations, high nuclear/cytoplasmic ratios, hyperchromatic to open/vesicular nuclei and macronucleoli. The majority of cases additionally showed hypercellular, three-dimensional fragments in a background of lymphocytes. The fragments displayed syncytial architecture without molding and rarely squamous differentiation. All cases lacked follicular differentiation, intranuclear inclusions, nuclear molding, or neuroendocrine-type chromatin.

CONCLUSIONS

Cytopathological features alone do not appear to be distinctive or definitive of CASTLE but rather allow for the inclusion of CASTLE within the differential diagnosis. Procurement of cell block material is important and resulted in the single case of CASTLE accurately diagnosed on FNA. Cytopathological features that favored CASTLE included syncytial fragments of malignant cells with pleomorphic large nuclei, vesicular chromatin, and prominent nucleoli in a background of lymphocytes. These cytopathological findings in the appropriate clinicoradiological context warrant its inclusion in the reported differential diagnosis in order to be able to implement appropriate clinical management.

Carcinoma of the Neck Showing Thymic-like Elements (CASTLE): Report of a Case and Review of the Literature

Carcinoma showing thymic-like elements (CASTLE) is a rare tumor affecting thyroid and neck soft tissues, which has to be distinguished from squamous cell and anaplastic thyroid carcinoma, because it has a better prognosis. We report a new case of CASTLE which occurred in a patient submitted to total thyroidectomy with central neck dissection. The tumor stained positively for CD5, which seems to be the most useful marker in the differential diagnosis. By the analysis of the 18 cases reported in literature, total thyroidectomy with selective modified neck dissection should be the treatment of choice and radiotherapy should be considered for patients with positive nodal status.

CT and MR imaging of thyroid carcinoma showing thymus-like differentiation (CASTLE): a report of ten cases

OBJECTIVE

To study the CT and MR imaging features of carcinoma showing thymus-like differentiation (CASTLE) and to raise awareness of this rare thyroid tumour.

METHODS

The imaging appearances of 10 CASTLE tumours confirmed by surgical pathology were retrospectively reviewed and correlated with clinical and histological findings.

RESULTS

Seven patients with newly diagnosed and three patients with recurrent tumours were identified (six males and four females). CASTLE tumours were commonly located in the lower neck between the inferior pole of the thyroid and the upper mediastinum. The average tumour size was 4.2 cm (range: 2.5-6 cm). On plain CT scans, most tumours were ill-defined nodular masses of uniform density. After enhancement, most cases showed mild enhancement, while heterogeneous enhancement could be seen in more than half the cases. On the MR images, tumours presented with homogeneous isointensity on T1 weighted images and they appeared to be slightly hyperintense on T2 weighted images. On post-contrast images, marked enhancement was seen in two patients, and heterogeneous enhancement was seen in three cases. Aggressive local infringements mainly included the ipsilateral strap muscle, tracheoesophageal groove area and tracheal wall. The specimens stained positively for CD5 and CD117, indicating thymic differentiation.

CONCLUSION

CASTLE has no characteristic imaging features when compared with other thyroid nodules, except for its unique location in the lower neck between the inferior pole of the thyroid and the upper mediastinum. CD5- and CD117-specific immunoreactivity is useful for diagnosis.

ADVANCES IN KNOWLEDGE

We reported 10 cases of CT and MR images illustrating the features of CASTLE, and we raised the level of awareness of this rare malignant thyroid tumour.

Thyroid Carcinoma Showing Thymic-Like Differentiation Causing Fracture of the Trachea

Thyroid carcinoma showing thymic-like differentiation (CASTLE) comprises a rare neoplasm of the thyroid gland which arises from ectopic thymic tissue or remnants of brachial pouches. CASTLE is regarded as an indolent neoplasm with a favorable prognosis, irrespective of its metastatic potential. Diagnosis is difficult as clinicopathological features have not been yet well-defined. Radiological findings are not specific and only immunohistochemical positivity for CD5 and CD117 staining is highly suggestive of CASTLE. Despite lack of universally accepted treatment recommendations, the mainstay treatment includes thyroidectomy and systematic lymph node dissection. We report a case of CASTLE tumour with very uncommon characteristics developed in a 76-year-old man, who presented with rapidly deteriorating dyspnea and severe cough, resulting in respiratory failure. At surgery, a suspicious looking tumour arising from the upper pole of the right lobe of the thyroid gland, surrounding the trachea and displacing the right common carotid artery, was identified. The patient underwent en bloc resection of the tumour with the thyroid gland and regional lymph node dissection. This is the first reported case of CASTLE causing tracheal ring fracture.

Clinical analysis of 82 cases of carcinoma showing thymus-like differentiation of the thyroid

The aim of the present study was to summarize the clinical characteristics, diagnosis, treatment and prognosis of carcinoma showing thymus-like differentiation of the thyroid (CASTLE). A search of the relevant literature was conducted, which identified 82 cases of CASTLE reported to date. A review of the clinical and auxiliary examination data, treatment, pathological findings and follow-up of these cases was performed. The clinical manifestations of CASTLE varied and did not demonstrate specificity. During ultrasound examination, CASTLE was described as a solid and hypoechoic mass, and the echo was typically observed to be heterogeneous. In computed tomography (CT), CASTLE was demonstrated to be a well-defined, soft tissue density mass without calcification, which appeared enhanced following administration of contrast medium. In emission CT, CASTLE was revealed as a ‘cold nodule’. A total of 78 patients underwent radical surgery, and 12 patients experienced recurrence. Lymph node metastasis did not promote recurrence, and postoperative radiation was not able to reduce the recurrence rate (P=0.144 and 1.000, respectively). The median follow-up time was 14 months (range, 1–312 months). Typical immunohistochemical examinations demonstrated the specimens to be positive for cluster of differentiation (CD)5, CD117, cytokeratin 19, epithelial membrane antigen and tumor protein 63, and negative for calcitonin, thyroglobulin and thyroid transcription factor-1. Thyroid CASTLE is a rare malignancy whose exact diagnosis relies on pathological examination, particularly immunohistochemistry, since preoperative examinations are usually unable to provide an exact diagnosis. Radical resection is the primary treatment for CASTLE, which presents favorable prognosis.

Chemosensitivity in Carcinoma Showing Thymus-Like Differentiation: A Case Report and Review of the Literature

BACKGROUND

Carcinoma showing thymus-like differentiation (CASTLE) is an extremely rare malignant neoplasm of the thyroid that originates from ectopic thymic tissue. No sufficient evidence exists regarding the efficacy of chemotherapy for cases with distant metastases or advanced disease because of the rarity of the disease itself.

PATIENT

We report a case of CASTLE with lung metastasis that showed good responses to first-line (cisplatin, doxorubicin, vincristine, and cyclophosphamide) and second-line (carboplatin and paclitaxel) chemotherapies.

SUMMARY

This is the first case of CASTLE reported to show a good response to two serial chemotherapies.

CONCLUSION

This case suggests that CASTLE is a chemosensitive tumor and that chemotherapy should be attempted in patients with advanced or metastatic CASTLE.

Thyroid carcinoma showing thymus-like elements: a clinicopathologic, immunohistochemical, ultrastructural, and molecular analysis

OBJECTIVES

To investigate the clinicopathologic, immunophenotypic, ultrastructural, and molecular features of thyroid carcinoma showing thymus-like elements (CASTLE).

METHODS

We retrospectively analyzed the clinicopathologic data of 10 patients with CASTLE and described the immunophenotypic and ultrastructural features of these tumors. The expression of Epstein-Barr virus-encoded RNA and the gene status of EGFR, C-KIT, and HER-2 were also assessed by molecular techniques.

RESULTS

The tumor cells were positive for CD5, CD117, p63, HMWK, EGFR, GLUT-1, Pax8, E-cadherin, bcl-2, and p53 in all cases and for CA-IX, CEA, p16, HER-2, and neuroendocrine markers in some cases. Ultrastructural examination indicated that the tumor cells contained large quantities of tonofilament with abundant intercellular desmosomes, including intracytoplasmic neuroendocrine granules in one case. EGFR gene amplification in two patients and polyploidy of chromosome 7 in one patient were identified by fluorescence in situ hybridization. Sequencing analysis revealed that a synonymous mutation, Q787Q 2363 (G→A), occurred on exon 20 of the EGFR gene in three patients.

CONCLUSIONS

GLUT-1 can be used as a novel biomarker for CASTLE, and combined detection of GLUT-1 with CD5 and CD117 aids in the diagnosis of this tumor. Aberrant expression of Bcl-2, p53, p16, E-cadherin, EGFR, C-KIT, and HER-2 may play important roles in the development of CASTLE.

A case of carcinoma showing thymus-like differentiation with a rapidly lethal course

A 55-year-old woman underwent a total thyroidectomy for carcinoma showing thymus-like differentiation (CASTLE). The patient was referred to our hospital after the tumor was found to have directly invaded the cervical esophagus and the entire circumference of the trachea. A total thyroidectomy was performed, followed by end-to-end anastomosis of the trachea, suprahyoid release and dissection of bilateral pulmonary ligaments. No major complications, including anastomotic dehiscence or stenosis, were observed. The patient experienced some swallowing disturbances and hoarseness during the perioperative period but fully recovered. Radiotherapy to the neck was performed as an adjuvant therapy. Eleven months after surgery, lower back pain and right leg numbness developed and led to gait inability. Multiple lung and bone recurrences were observed, but no local recurrence. Palliative radiotherapy to the bone metastasis was performed. The patient died of pleural metastasis 14 months after the initial diagnosis of CASTLE.

Thyroid carcinoma showing thymus-like differentiation: Case presentation of a young man

Ectopic thymic tissue can be present in the thyroid gland and a carcinoma showing thymus-like differentiation (CASTLE) may arise from such tissue. We are reported the case of a 26-year-old man with CASTLE, with cervical subcutaneous nodules relapse, who showed a good response to treatment with surgery, chemotherapy and radiotherapy. The problematic aspect of this case was the diagnosis; only on review were we able to make a final diagnosis. CASTLE is a very rare neoplasm. It is important to differentiate this cancer from others tumors such as primary or metastatic squamous cell carcinoma of the head and neck or squamous cell thyroid carcinoma, because the therapy and prognosis are different. Diagnosis is complicated and requires careful histological analysis (CD5- and P63-positive with presence of Hassall’s corpuscles); unfortunately there is no gold standard treatment so, in this case, we administered a sandwich of chemotherapy and radiotherapy.

Potential Role of Adjuvant Radiation Therapy in Cervical Thymic Neoplasm Involving Thyroid Gland or Neck

PURPOSE

The purpose of this study is to assess the clinicopathologic features, treatment outcomes, and role of adjuvant radiation therapy (RT) in cervical thymic neoplasm involving the thyroid gland or neck.

MATERIALS AND METHODS

The medical and pathologic records of eight patients with cervical thymic neoplasm were reviewed retrospectively. All patients underwent surgical resection, including thyroidectomy or mass excision. Adjuvant RT was added in five patients with adverse clinicopathologic features. The radiation doses ranged from 54 Gy/27 fractions to 66 Gy/30 fractions delivered to the primary tumor bed and pathologically involved regional lymphatics using a 3-dimensional conformal technique.

RESULTS

Eight cases of cervical thymic neoplasm included three patients with carcinoma showing thymus-like differentiation (CASTLE) and five with ectopic cervical thymoma. The histologic subtypes of ectopic cervical thymoma patients were World Health Organization (WHO) type B3 thymoma in one, WHO type B1 thymoma in two, WHO type AB thymoma in one, and metaplastic thymoma in one, respectively. The median age was 57 years (range, 40 to 76 years). Five patients received adjuvant RT: three with CASTLE; one with WHO type B3; and one with WHO type AB with local invasiveness. After a median follow-up period of 49 months (range, 11 to 203 months), no recurrence had been observed, regardless of adjuvant RT.

CONCLUSION

Adjuvant RT after surgical resection might be worthwhile in patients with CASTLE and ectopic cervical thymoma with WHO type B2-C and/or extraparenchymal extension, as similarly indicated for primary thymic epithelial tumors. A longer follow-up period may be needed in order to validate this strategy.

Clinical analysis of thyroid carcinoma showing thymus-like differentiation: report of 8 cases

Thyroid carcinoma showing thymus-like differentiation (CASTLE) is a kind of rare neoplasm of the thyroid gland. Because thyroid CASTLE is rare and difficult to diagnose, its clinicopathologic features have not been well defined, and no universally accepted treatment recommendation is available. We analyzed retrospectively the clinicopathologic data of 8 patients with thyroid CASTLE who underwent surgery and radiotherapy at the Shengjing Hospital of China Medical University between December 2008 and June 2012. All patients accepted radical surgery. All patients accepted postoperative radiotherapy, except one 79-year-old patient. There was no evidence of recurrence or metastasis during the follow-up period. The pattern of immunohistochemical staining was similar to that of thymic carcinoma. Six of 8 CASTLE cases expressed CD5. All 8 CASTLE patients were negatively expressed in thyroglobulin, thyroid transcription factor 1, and calcitonin. Patients with thyroid CASTLE have good outcomes after radical resection and postoperative radiotherapy. Positive CD5 immunoreactivity can contribute to diagnosis of this disease.

Management of thyroid carcinoma showing thymus-like differentiation (CASTLE) invading the trachea

PURPOSE

To define the clinicopathological features and discuss the optimal management of carcinoma showing thymus-like differentiation (CASTLE).

METHODS

We retrospectively analyzed six patients with CASTLE.

RESULTS

The subjects comprised two men and four women (average age at initial diagnosis, 61 years, range 47-75 years). Preoperative biopsy yielded a correct diagnosis in two patients. Five patients underwent surgery and one was treated with radiation therapy alone. Four had extrathyroidal invasion and three had lymph node metastasis. During the clinical course, tracheal invasion was detected in five patients, the upper extent of the tumor being the lower half of the first tracheal ring. Two of these patients underwent tracheal sleeve resection. Two patients received postoperative radiotherapy for nodal metastasis, and one, after palliative surgery. The median follow-up period was 67 months (range 38-129). Recurrence was found 10 years post-therapy in the patient treated with radiation therapy only, resulting in death soon after. Although local recurrence was not found in the remaining five patients, new pulmonary metastases were diagnosed in the patient who underwent non-curative surgery.

CONCLUSIONS

CASTLE can be diagnosed preoperatively by core needle biopsy and CD5 staining. Curative resection with neck dissection followed by radiotherapy can yield a good outcome. Larynx-sparing complete resection may be more feasible for CASTLE, even though it has a higher incidence of tracheal invasion than differentiated thyroid carcinoma.

Outcome of radical resection and postoperative radiotherapy for thyroid carcinoma showing thymus-like differentiation

BACKGROUND

Carcinoma showing thymus-like differentiation (CASTLE) is a rare disease that is difficult to diagnose. The aim of this study was to assess the effects of combined-modality treatment in CASTLE patients.

METHODS

We retrospectively studied patients identified between January 1, 2000 and December 31, 2009 as having CASTLE and who subsequently underwent surgery and radiotherapy or chemotherapy. Preoperative laboratory findings, ultrasonographic (US) and computed tomographic (CT) features, and fine-needle aspiration biopsy (FNAB) specimens were evaluated.

RESULTS

Seven patients with CASTLE were identified (four men, three women). The median age at initial diagnosis was 48 years (range 25-56 years). The five newly diagnosed patients were treated with curative surgery and postoperative radiotherapy, whereas two patients with recurrent disease were treated with salvage surgery plus radiotherapy or chemotherapy. All patients were disease-free at a median follow-up period of 34 months (range 12-61 months). The pattern of immunohistochemical staining was similar to that of thymic carcinoma. Specimens from all seven patients stained positively for CD5, CD117, and cytokeratin but were uniformly negative for thyroglobulin, thyroid transcription factor 1 (TTF-1), and calcitonin.

CONCLUSIONS

Patients with CASTLE have excellent outcomes after curative resection and postoperative radiotherapy compared with patients with anaplastic thyroid carcinoma. Even patients with local recurrent disease benefited from salvage surgery with subsequent operation and/or radiotherapy. CD5 immunohistochemical staining on FNAB samples may help identify the possible entities that are part of the differential diagnosis.

Thyroid carcinoma showing thymus-like differentiation (CASTLE): case report with cytomorphology and review of the literature

Thyroid carcinoma showing thymus-like differentiation (CASTLE) is a rare tumor of the thyroid gland or adjacent soft tissues of the neck. Given the comparatively good prognosis of CASTLE, it is crucial to distinguish this neoplasm from other more aggressive thyroid neoplasms that can have similar or overlapping cytomorphological features. However, there is little information about the cytomorphology of CASTLE available in the literature. Here we report the cytomorphology and histology of thyroid CASTLE in a 52-year-old woman and present a review of the literature.

Management of carcinoma showing thymus-like element

OBJECTIVE

To consolidate the key features of carcinoma showing thymus-like element, including its management.

METHOD

We present our experience of the difficult diagnosis and management of this rare tumour. We also present the results of an extensive literature search, documenting those aspects of the clinical picture, natural history and management of carcinoma showing thymus-like element which are relevant to head and neck surgeons.

RESULT

Intrathyroidal, epithelial carcinoma showing thymus-like element is a rare, malignant tumour of the thyroid gland, with histopathological features similar to squamous cell carcinoma but a more favourable prognosis. It is usually treated surgically using a combination of total thyroidectomy and selective neck dissection, with radiotherapy and chemotherapy in selected cases.

CONCLUSION

Carcinoma showing thymus-like element of the thyroid gland is a rare condition. Head and neck surgeons with a thyroid interest should be aware of this tumour, because of its close histological resemblance to other, commoner malignancies of the thyroid gland.

CASTLE tumour of the neck: a rare location of a malignant tumour of the thymus

We present the case of a 62-year-old woman who consulted her physician in December 2005, suffering from a mass at the left lower anterior neck with rapid enlargement. Intraoperative frozen section was highly suspicious of a CASTLE tumour (carcinomas showing thymus-like differentiation). Finally, immunohistochemical investigation revealing positivity for CK5/6, c-kit (CD117) and CD5 as well as negativity for thyroglobulin, calcitonin, vimentin and TTF-1 confirmed the diagnosis. Due to lymph node metastases, radiochemotherapy was performed. Fifteen months after the initial diagnosis disseminated pulmonary metastases were found and treated with cisplatin based chemotherapy, which led to a stabilisation of the disease. In June 2008, computed tomography showed progress of the pulmonary metastases, making further chemotherapeutical treatment necessary. Although treatment was changed in October 2008, the staging evaluation in January 2009 revealed further progress of the metastatic disease. Currently, the patient is still alive, but receives no medical treatment at the moment.

Carcinoma showing thymus-like differentiation (CASTLE) of thyroid: a case report and literature review

Carcinoma showing thymus-like differentiation (CASTLE) is a rare malignant neoplasm that occurs in the thyroid gland, or head and neck. This tumor arises from either ectopic thymus tissue or remnants of branchial pouches, which retain the potential to differentiate along the thymus line. Clinical presentation and imaging can be consistent with a malignant lesion such as thyroid cancer or thymic carcinoma. Immunohistochemical staining with CD5 can differentiate CASTLE from other malignant thyroid neoplasms. A 54-year-old male had initially presented with a painless, left neck mass for 3 months. He underwent left thyroid lobectomy via a median sternotomy approach. Carcinoma showing thymus-like differentiation was the final histopathologic diagnosis. After 36 months of follow-up, no evidence of recurrence was observed. A median sternotomy is an excellent approach for CASTLE with anterior mediastinum involvement. Complete resection is important to improve the long-term survival rate and the locoregional recurrence rate.

Carcinoma showing thymus-like differentiation (CASTLE) with neuroendocrine differentiation

Carcinoma showing thymus-like differentiation (CASTLE) is a rare malignant neoplasm that histologically resembles thymic carcinoma and arises in the thyroid gland or adjacent soft tissue of the neck. Herein is reported the case of a 62-year-old male patient with CASTLE exhibiting neuroendocrine differentiation, who was treated with total pharyngolaryngo-esophagectomy and total thyroidectomy. Gross examination of the surgical specimen showed a grayish-white, solid, lobulated tumor, mainly located between the trachea and esophagus, and involving the lower part of the left thyroid lobe. Histologically, the tumor consisted of epithelial cell nests separated by thick fibrous septa. The tumor cells were polygonal in shape, and contained pale cytoplasm and a vesicular nucleus with prominent nucleoli. There were few mitotic figures. Rosette-like arrangements that suggested neuroendocrine differentiation were observed in part of the tumor. The tumor cells were positive for CD5 and neuroendocrine markers including synaptophysin and chromogranin A.

Aggressive thyroid carcinoma showing thymic-like differentiation (CASTLE): case report and review of the literature

Carcinoma showing thymic-like differentiation (CASTLE) is a rare tumour of the thyroid, which arises from ectopic thymic tissue or remnants of branchial pouches. A systematic review of English literature evidences less than thirty cases; from them, it clearly appears that CASTLE is considered an indolent slow-growing neoplasia even when lymph nodes metastasis are present. We describe a case of very aggressive CASTLE, which showed seeding along fine needle aspiration tract.

[Thyroid carcinoma with thymus-like differentiation (CASTLE): case report and review of the literature]

Carcinoma with thymus-like differentiation (CASTLE) is a rare malignant epithelial tumor which arises on soft tissue of the neck or thyroid gland. It is important to differentiate CASTLE from primary or metastatic squamous cell carcinoma of head and neck, and from squamous cell thyroid carcinoma, because it has a different prognosis. CD5 immunoreactivity might be helpful in CASTLE diagnosis. CASTLE behaves generally in an indolent fashion, even though it has a high relapse rate, while the other have a dismal prognosis due its high dissemination rate. Treatment includes surgical excision and radiotherapy. Chemotherapy can be offered, although its efficacy is not clear. Authors present a case of a 52 year-old male that complaints with cough, disphony, asthenia, and thyroid mass. Thyroidectomy was performed and the pathology revealed a CASTLE. After radiotherapy and chemotherapy, minimal response was obtained. The authors intend to discuss the differential pathologic diagnosis and the best therapy of this indolent but recurrent neoplasm, that demands strict long term follow-up.

Primary squamous cell carcinoma of the thyroid: immunohistochemical profile and literature review

BACKGROUND

Squamous cell carcinoma accounts for 1% of primary thyroid malignancies and is characterized by a rapidly unfavorable outcome.

CASE PRESENTATION

A 64-year-old woman presented with a painless mass in the left neck, coexisting with thyroid goiter. Total thyroidectomy with lymphadenectomy was performed and a primary thyroid squamous cell cancer was confirmed histologically after excluding any other possible primary malignancies. The tumor's immunohistochemical profile was explored using a large panel of antibodies. The tumor featured a positive immunoreaction to cytokeratins 7-19 and to squamous cell carcinoma antigen. Low-molecular-weight cytokeratins 5-6 and epithelial membrane antigen were also expressed. The neoplasm's proliferative index (Mib1) was 60%. No immunostaining was detected for cytokeratins 10-20, thyroglobulin, TTF-1, CD5, galectin-3 or p53.

CONCLUSIONS

This case of primary thyroid squamous cell carcinoma immunohistochemically profiled using a large panel of immunoreactions may offer useful information on the histological differentiation of thyroid squamous cell carcinoma from other (uncommon) thyroid carcinomas and the distinction between primary and secondary thyroid cancers.

Carcinoma showing thymus-like element (CASTLE) of thyroid: combined modality treatment in 3 patients with locally advanced disease

OBJECTIVES

To examine the value of chemotherapy, radiotherapy and surgery for treatment of locally advanced carcinoma showing thymus-like element (CASTLE) of the thyroid.

METHODS

Retrospective analysis of 3 Chinese patients in a tertiary referral center in Hong Kong.

RESULTS

CASTLE is a rare thyroid malignancy with a frequency of only 0.15% (3/2033 patients) in our center. Three patients (M:F=2:1) aged 43, 49 and 62 years were studied. All 3 patients had advanced T4 disease with extensive tracheal infiltration and airway compression. None had lymph node or distant metastasis. Total thyroidectomy, combined with chemotherapy and radiotherapy, was effective in local control and symptom relief. Etoposide and carboplatin were tried in 2 patients with positive response. Neoadjuvant chemotherapy shrank the tumor rapidly and relieved symptoms of airway compression. All 3 patients had external radiotherapy resulting in good local control. In a patient with inoperable disease, chemotherapy and radiotherapy rendered the disease operable. All 3 patients were symptom-free and alive at 6, 2.5 and 1.8 years after diagnosis.

CONCLUSIONS

CASTLE is locally infiltrative and presents at advanced T stage in this small series. Chemotherapy and radiotherapy, apart from surgery, are effective treatment modalities. In cases of inoperable disease or advanced local disease, they can be employed in combination with surgery. Organ preservation of larynx and trachea may be achieved. Chemotherapy can be very useful for rapid relief of symptoms, especially in shrinking tumor to prevent airway obstruction.