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

Carcinoma Showing Thymus-Like Differentiation (CASTLE): A Case Report and Review of the Literature

Carcinoma showing thymus-like differentiation (CASTLE) is a rare tumor occurring in the thyroid and soft tissues of the neck. Treatments and prognosis for CASTLE significantly differ from those associated with squamous cell carcinoma and anaplastic thyroid carcinoma. To date, fewer than 100 cases have been reported. Given the lack of a standardized treatment protocol and the diagnostic complexity, documenting these cases is essential. A 74-year-old male patient was admitted to the hospital due to hoarseness lasting for 1 month and thyroid nodules for over 2 weeks. The ultrasound revealed a grade 4 nodule in the left thyroid, and the needle biopsy reported the presence of glandular epithelial cells of varying sizes, some arranged in a papillary pattern, and was negative for BRAF mutation. Thyroid surgeons performed a left partial thyroidectomy and a left cervical lymph node biopsy, and the immunohistochemical staining led to a diagnosis of intrathyroid thymus carcinoma. Follow-up on his postoperative recovery shown no signs of local recurrence or distant metastasis during this period. This paper conducts a systematic review of the literature to enhance understanding, diagnosis, treatment, and prognosis of this condition. The goal was to raise clinical awareness and guide appropriate treatment strategies.

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.

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.

Carcinoma showing thymus like elements: Report of a case with EGFR T790M mutation

Carcinoma showing thymus-like differentiation of the thyroid (CASTLE) is a rare tumor involving the thyroid and perithyroidal soft tissues. It shares morphological, immunohistochemical and molecular similarities with thymic carcinomas. Due to its relatively better prognosis, it needs differentiation from other primary and metastatic tumors of this region. A 40-year-old lady presented with a gradually progressive anterior neck swelling for one year. Imaging showed bulky right and left lobes of thyroid along with a solid soft tissue mass in the pretracheal region. Fine needle aspiration smears showed features of poorly differentiated carcinoma. Total thyroidectomy with excision of the mass revealed histopathological features characteristic of CASTLE, with evidence of thyroiditis in adjoining thyroid. Epidermal growth factor receptor (EGFR) assay revealed presence of EGFR T790M somatic mutation in exon 20. The same was not detectable on direct sequencing. We present a rare case of CASTLE, occurring in association with Hashimoto thyroiditis, with emphasis on cytological features and report for the first time the presence of a low level somatic mutation in EGFR (EGFR T790M mutation).

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.

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.

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.

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.

Cytological findings of intrathyroidal epithelial thymoma/carcinoma showing thymus-like differentiation: a study of eight cases

The purpose of this article is to describe the cytologic findings of intrathyroidal epithelial thymoma/carcinoma showing thymus-like differentiation (ITET/CASTLE) in detail and discuss its differential diagnoses. We examined cytologic specimens taken from eight ITET/CASTLE cases, who underwent fine needle aspiration. Cytologic features of ITET/CASTLE include (1) hypercellularity, (2) large cell clusters without papillary or follicular pattern, (3) round or spindle tumor cells with distinct nucleoli and cell border, (4) few keratinized cells and intracytoplasmic lumina (ICL), and (5) lymphocytic background. The differential diagnoses included poorly differentiated carcinoma, metastatic lymphoepithelioma, squamous cell carcinoma, and mucoepidermoid carcinoma. The presence of individual keratinizing cells and ICL and the location of the tumor may be helpful in indicating ITET/CASTLE.

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.

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.