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

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.

Intrathyroidal Thymic Carcinoma: A Retrospective Case Series Study

OBJECTIVE

Intrathyroidal thymic carcinoma (ITC) is a rare low-grade malignant thyroid tumor. There is neither sufficient understanding of this tumor nor its clinical treatment. This study is to explore the clinicopathological features, treatment, and prognosis of ITC and thereby provide a reference for the diagnosis and treatment of the disease.

METHODS

The clinical, pathological, therapeutic, and prognostic data of 13 patients with ITC were retrospectively analyzed.

RESULTS

The case series comprised 7 males and 6 females, with an average age of 51.9 ± 10.1 years. After surgical resection, all patients received post-operative neck radiotherapy at dosages of 60-66 Gy. Five patients with level VI lymph node metastasis additionally received 6 courses of cisplatin chemotherapy. All patients were followed-up for 21-132 months (median = 66 months), and all of them survived without recurrence or metastasis.

CONCLUSIONS

The diagnosis of ITC depends mainly on pathological and immunohistochemical results, particularly CD5 positive staining. Surgical resection is the preferred primary treatment modality which can be supplemented with radiotherapy and chemotherapy to reduce the risk of recurrence and metastasis.

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.

Case report and literature review: thyroid carcinoma showing intrathyroid thymic carcinoma

Background

Intrathyroid thymic carcinoma (ITTC) is a rare malignancy of the thyroid gland with histological and immunophenotypic resemblance to thymic carcinoma. Surgery combined with adjuvant radiotherapy improves the survival of patients with ITTC. However, for patients with extensive metastases, there is currently no effective treatment. Chemotherapy is an option but has not demonstrated improved patient survival.

Methods and results

A female patient presented with metastases to the pleura, lung, and bone 16 years after surgery for ITTC. As radiotherapy and chemotherapy failed to control the recurrent disease, lenvatinib treatment was initiated. After 3 months, positron emission tomography/computed tomography showed a substantial reduction of all metastatic lesions and decreased tumor metabolism. The patient continues to receive lenvatinib and remains well and symptom-free.

Conclusion

For patients with ITTC who have progressive, life-threatening metastases, lenvatinib represents a valuable salvage therapy that may offer a sustained reduction in tumor burden and maintenance of quality of life.

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.

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.

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

Intrathyroidal thymic carcinoma exhibiting neuroendocrine differentiation: Case report with cytomorphology, immunocytochemistry, and review of the literature focusing on cytology

Intrathyroidal thymic carcinoma is a malignant epithelial tumor of the thyroid gland with thymic epithelial differentiation; it is the malignant counterpart of ectopic thymoma of the thyroid gland and histologically resembles thymic carcinoma. Given its favorable prognostic course, preoperative cytological diagnosis is important 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 cytology of this disease available in the literature, even in the latest fourth edition of World Health Organization classification of tumors of endocrine organs. Here, we report a case of intrathyroidal thymic carcinoma exhibiting neuroendocrine differentiation in a 33-year-old woman and present a review of the literature.

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.

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.

Secondary tracheal tumors: a systematic review

BACKGROUND

Secondary tracheal tumors arise from mural invasion by primary tumors in adjacent organs, metastatic lymph nodes or blood-born metastasis from distant sites. This systematic review aims to assess the presentation, management options, and clinical outcomes of these uncommon non-tracheal malignancies.

METHODS

Electronic searches of the MEDLINE database were performed to identify case series and individual case reports of tracheal invasion by primary non-tracheal tumors or metastatic disease. All English-language studies with available abstracts or articles containing primary data were included.

RESULTS

From 1978 to 2017, a total of 160 case reports or case series identified 2,242 patients with invasion of the trachea by tumors of adjacent organs (n=1,853) or by metastatic lymph nodes or hematogenous spread (n=389). Common primary sites of origin were thyroid, esophagus, and lung, and the most common presentation was metachronous (range of interval: 0 to 564 months) with dyspnea, neck mass, voice change and/or hemoptysis. A majority of patients in case reports (77.9%) and case series (66.0%) underwent resection and the most common reported operation was segmental tracheal resection. Fewer patients underwent bronchoscopic intervention (21.7%) and radiation was used in 32.2% of patients. Complications after bronchoscopic treatment included bleeding, granulation tissue, and retained secretions, while anastomotic leak, unplanned tracheostomy, and new recurrent laryngeal nerve paralysis were observed after surgical resection. The rate of 30-day mortality was low (0.01-1.80%). Median survival was higher in patients with thyroid malignancy and in patients who underwent surgical management. Follow-up time ranged from 0.03 to 183 months.

CONCLUSIONS

Patients with tracheal invasion by metastatic or primary non-tracheal malignancies should be assessed for symptoms, tumor grade, tumor recurrence and concurrent metastases to decide on optimal surgical, bronchoscopic or noninterventional therapy. Clinical experience suggests that palliative endoscopic intervention for tracheal obstruction by metastasis-bearing lymph nodes is underreported.

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.

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: 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.

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.

Solitary intrathyroidal metastasis of renal clear cell carcinoma in a toxic substernal multinodular goiter

Introduction

Thyroid gland is a rare site of clinically detectable tumor metastasis.

Case report

A 71-year-old woman was referred to our department for an evaluation of toxic multinodular substernal goiter. She had a history of renal clear cell carcinoma of the left kidney, which had been resected 2 years previously. US confirmed the multinodular goiter. Total thyroidectomy with neuromonitoring was performed on March 2008. A histological examination revealed a solitary metastasis of a clear cell renal cancer in a diffuse multinodular goiter. No distant metastases are detected.

Conclusion

Although uncommon, it is important for the endocrine surgeon and endocrine oncologist to be able to recognize and differentiate intrathyroid metastases from more primary common thyroid neoplasms. The diagnosis can be suspected if the patient has a thyroid tumor and a past history of extrathyroid cancer. These tumors, on the whole, tend to behave more aggressively and, in most cases, the use of multimodality therapy is recommended.

Unusual tumors of the thyroid gland

Thyroid neoplasms are classified into three major categories: epithelial, nonepithelial, and secondary. Most primary epithelial tumors of thyroid are derived from follicular cells. These include follicular adenoma and carcinoma (Hürthle and non-Hürthle), and papillary carcinoma and its variants. Other primary epithelial tumors include medullary carcinoma, mixed medullary and follicular carcinomas, insular and poorly differentiated carcinoma, anaplastic carcinoma, and the least common squamous carcinoma and related tumors. The nonepithelial tumors are rare; the most common include malignant lymphoma and tumors arising from the mesenchymal elements. The secondary tumors represent metastatic tumors to the thyroid usually originating in lung, kidney, and breast. In this article, the authors review the unusual tumors of the thyroid, their morphologic features, and clinical and prognostic implications.

[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.

Unusual spindle cell tumor of thyroid (SETTLE)

Spindle epithelial tumor with thymus-like differentiation (SETTLE) is a rare tumor seen mostly in children and adolescents. It is presumed that it arises from ectopic thymus or remnants of branchial pouches that differentiate along the thymic line. Unusual spindle cell-predominant histology makes this entity difficult to recognize. The clinical course is not exactly known due to the small number of reported cases but metastasis has been documented during initial presentation. We report a case of SETTLE in the neck where preoperative clinical and radiological impression was that of a mass in the left submandibular gland area. However, during the operation it was felt by the surgeon that the mass was in continuity with the left thyroid lobe.