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

Carcinoma Showing Thymus-like Differentiation (CASTLE) with Synchronous Papillary Thyroid Carcinoma: A Case Report and Review

Carcinoma showing thymus-like differentiation (CASTLE) is a rare malignant tumor that accounts for 0.1%-0.15% of all thyroid cancers. More than half of the patients have tumor extension to adjacent organs, including the recurrent laryngeal nerve, trachea, and esophagus. The diagnosis of CASTLE is based on histology and immunohistochemistry. A 58-year-old female patient complained of hoarseness for one and half years. Right side vocal cord palsy was diagnosed by fiberscopy. Thyroid sonography revealed right thyroid tumors, which were reported to be papillary thyroid carcinoma through FNAC. Total thyroidectomy with central lymph node dissection was performed. Pathologist found 2 isolated malignancy tumors. One patient in the right thyroid lobe had papillary thyroid carcinoma features. The other extrathyroid tumor seemed to be separated from the first tumor and invaded the thyroid capsule. After multiple immunohistochemical studies, PTC synchronous CASTLE was the final diagnosis. Coexisting PTC and CASTLE is very rare. This is the first report to describe a case showing PTC at first, while subsequent pathologic examination revealed the presence of CASTLE in addition to PTC. Since the prognosis of CASTLE is favorable, the treatment is different from other aggressive thyroid cancers, such as poorly differentiated or anaplastic thyroid carcinoma.

Coexistence of intrathyroid thymic carcinoma and papillary thyroid carcinoma: a case report and literature review

Background

Intrathyroid thymic carcinoma (ITTC) is a rare neoplasm of the thyroid, which accounts for less than 0.15% of all thyroid malignancies. The coexistence of ITTC and papillary thyroid carcinoma (PTC) is an extremely rare condition reported only in a limited number of cases.

Case summary

A 26-year-old female presented with a growing neck mass, hoarseness, and dysphagia over four months. Ultrasonography revealed that the entire left lobe and the isthmus of the thyroid were replaced with a hypoechoic mass. Moreover, it revealed two hypoechoic nodules in the right thyroid. The patient underwent a total thyroidectomy and paratracheal lymph node dissection. Histopathological examinations revealed the coexistence of ITTC and PTC in the same thyroid. In immunohistochemical analyses, the ITTC was positive for CD5, P63, CD117, and CK 5/6 and negative for thyroglobulin, calcitonin, and TTF 1. At the same time, PTC was positive for TTF 1 and thyroglobulin and negative for CD5, P63, and CK 5/6. The patient received postoperative radiotherapy and remained well with no evidence of recurrence during one month follow-up.

Conclusion

Distinguishing ITTC from other thyroid malignancies before the surgery is challenging due to its non-specific presentations. Therefore, the diagnosis relies on postoperative studies, especially immunohistochemistry. The recommended treatment approach to improve survival in ITTC cases is total thyroidectomy combined with cervical lymph node dissection, followed by postoperative radiotherapy. The coexistence of ITTC and PTC may indicate the similarity in the underlying mechanisms of these tumors. However, further investigations are needed to understand this potential correlation.

Case Reports: A role of postoperative radiation therapy in completely resected early stage intrathyroid thymic carcinoma: a case report and literature review of the diagnosis and treatment

Background

Intrathyroid thymic carcinoma (ITTC) is a rare malignant tumor of the thyroid, probably arising from ectopic thymus or branchial pouch remnants. Most of the literature recommended radical resection as the fundamental treatment for ITTC, and postoperative radiation appears to be able to reduce the recurrence rate in patients with advanced ITTC. However, the issue of adjuvant radiotherapy in completely resected early-stage ITTC has been controversial.

Case presentation

Here, we reported a new case of early-stage ITTC that treated with total thyroidectomy and the right central neck dissection. Postoperative external beam radiation therapy (50.0 Gy/25 fractions) was given to the thyroid bed and bilateral cervical lymph node area since the tumor involved part of the sternal thyroid muscle. At 4-year follow-up after completion of radiotherapy, she is without evidence of locally recurrent or distant disease.

Conclusion

Since there are no current guidelines for early-stage ITTC, in combination with this case and previous literature, we may suggest routine adjuvant radiotherapy should be considered in patients with incompletely resected tumors and extraparenchymal extension of ITTC. Moreover, we summarized comprehensive and advanced diagnosis, treatment, prognosis of ITTC and comparison between ITTC, primary squamous cell carcinoma of thyroid gland, differentiated thyroid cancer, and anaplastic thyroid cancer.

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.

A case of concurrent occurrence of carcinoma showing thymus-like differentiation and follicular variant of papillary thyroid cancer in the same thyroid

Carcinoma showing thymus-like differentiation (CASTLE) is a rare thyroid cancer. This is the first report of a case of concurrent occurrence of CASTLE with papillary thyroid carcinoma (PTC).

A 66-year-old male patient had hoarseness with right vocal cord paralysis. Ultrasonography revealed a hypoechoic nodule in the inferior pole of the right thyroid lobe. Ultrasound-guided fine-needle aspiration cytology suggested differentiated thyroid cancer. The patient underwent total thyroidectomy with neck dissection. Pathological examination revealed two different thyroid cancers: a CASTLE and a follicular variant of PTC. Postoperative radiation therapy was performed. The patient was still alive after 5 year following the initial treatment without evidence of recurrence. The oncological management of patients with concurrent occurrence of different thyroid cancers should consider the biological behavior of both tumors.

Carcinoma showing thymus-like differentiation (CASTLE) of the salivary gland: Report of 2 cases of a hitherto under-recognized extrathyroid counterpart

Carcinoma showing thymus-like differentiation (CASTLE) outside the thyroid gland is extremely rare. Here we report two cases of CASTLE of the major salivary gland. The tumors occurred in the parotid gland of a 31-year-old female (Case 1) and in the submandibular gland of a 40-year-old female (Case 2). Both tumors showed a lobulated growth pattern, and were histologically composed of a nested or sheet-like proliferation of carcinoma cells with round- to oval-shaped nuclei, distinct nucleoli and pale eosinophilic cytoplasm, accompanied by various degrees of lymphocytic infiltration. Immunohistochemical staining revealed that the tumors were positive for pan-cytokeratin, p40, CD5, CD117 and bcl-2. In addition, PD-L1 expression was seen in 10-90% of tumor cells. After the initial surgery, Case 1 remained tumor-free for 20 months, while Case 2 suffered lymph node recurrence at 4 months, followed by lung metastasis, which was treated with chemoradiotherapy and anti-PD-1 immune checkpoint inhibitor, resulting in a partial response. The present findings indicate that an extrathyroid counterpart of CASTLE can occur as a primary salivary gland neoplasm. Salivary CASTLEs seem to show a wide range of biological behavior, and long-term follow-up may be needed. Immune checkpoint inhibitor targeting PD-1 might become a promising treatment option in patients with CASTLE; however, further study with a larger number of cases is necessary to establish the optimal therapeutic strategy and prognostic factors for this rare cancer.

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.

A Rare Case of Thyroid Carcinoma Showing Thymus-Like Differentiation in a Young Adult

Thyroid carcinoma showing thymus-like differentiation (CASTLE) is thought to originate from ectopic thymic tissue or remnants of the developing thymus within or adjacent to the thyroid. This case report describes a mass located on the left thyroid of a 28-year-old man. Fine-needle aspiration cytology revealed a number of lymphoid cells without atypia that were similar to those seen in a malignant lymphoma of the thyroid, and surgery was performed. Based on additional histopathological findings, the tumor was finally diagnosed as a CASTLE. It is difficult to diagnose this neoplasm using fine-needle aspiration cytology. However, it is possible to differentially diagnose CASTLE based on its histological features. CD5 is useful for diagnosing CASTLE with immunohistochemical staining.

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.

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.

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.

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.

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.

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 differentiation with tracheal invasion

We describe a case of thyroid carcinoma showing thymus-like differentiation with tracheal invasion. The malignant tumor was managed by refined spiral tracheoplasty after tangential resection of the trachea. At 8 months after the surgery, computed tomography and bronchoscopy showed no tumor recurrence or tracheal stenosis.

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.

Carcinoma showing thymus-like elements of the thyroid gland: report of three cases including one case with breast cancer history

Carcinoma showing thymus-like elements (CASTLE) is a rare malignant tumor of the thyroid or adjacent neck soft tissues, whose histogenesis is still debated. It may resemble other primary or metastatic poorly differentiated tumors histologically and the differential diagnosis is crucial for CASTLE has a better prognosis. However, CASTLE as a second primary tumor has not been reported in the literature. We report three cases of thyroid CASTLE, including a unique tumor following breast-conserving surgery for early-stage breast invasive carcinoma. There were two female and one male. All three tumors were located in the right lobe of the thyroid, and one tumor showed extension into the surrounding soft tissue. Histologically, all tumors showed expansive growth and consisted of cords, nests or sheets of epithelial cells divided into irregularly shaped lobules by fibrous connective tissue with lymphoplasmacytic infiltration. Focal squamous differentiation resembling Hassall's corpuscles were observed. All cases stained positively for CD5, CD117, high molecular weight cytokeratin, cytokeratin, P63, carcinoembryonic antigen and epithelial membrane antigen. Positive staining for Bcl-2 in two cases and chromogranin A in one case was noted. Ki-67 expression ranged from 15 to 25%. Thyroid transcription factor and CD3 were negative. There was no evidence of recurrent or metastatic disease at following surgery. These features demonstrated CASTLE may arise from branchial pouch remnants, the thyroid solid cell nests. CASTLE is a rare entity, awareness of its occurrence as a second primary tumor is important to avoid overtreatment because it is associated with a favorable prognosis.

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.

Extrathyroid carcinoma showing thymus-like differentiation (CASTLE): a new case report and review of the therapeutic role of neck dissection and radiotherapy

We present here a case of extrathyroid CASTLE (the third case reported in the English literature) treated with excision and neck dissection without radiotherapy. Also, we reviewed the literature and analyzed the therapeutic results of each treatment modality for CASTLE. A 27-year-old male had initially presented with a painless, right neck mass for 2 months. Computed tomography of the neck showed a 3.8 × 3.2 × 3.8 cm heterogeneously enhancing mass at right level IIa, and no definite thyroid lesion was found. An excisional biopsy was done and the pathologic diagnosis was CASTLE. Then we performed a right modified radical neck dissection and right thyroid lobectomy. After three years, no evidence of tumor recurrence was noted. Total excision followed by neck dissection could be a sufficient surgical treatment option for CASTLE. Postoperative radiotherapy might be an alternative treatment option for neck dissection in patients with positive nodal status.

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.