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

Ultrasound-guided wire localisation: a GPS for hidden head and neck tumours? A case series

Objectives

Ultrasound-guided wire (USGW) localisation for small non-palpable tumours before a revision head and neck surgery is an attractive pre-operative option to facilitate tumour identification and decrease potential complications. We describe five cases of pre-operative USGW localisation of non-palpable head and neck lesions to facilitate surgical localisation and resection.

Methods

All patients undergoing pre-operative USGW localisation for non-palpable tumours of the head and neck region at London Health and Sciences Center, London, Ontario, Canada, were included. All the USGW localisations were performed by the same interventional radiologist, and the surgeries were performed by fellowship trained head and neck surgeons.

Results

Five patients were included. All patients were undergoing revision surgery for recurrent or persistent disease. All successfully underwent a pre-operative USGW localisation of the non-palpable lesion before revision surgery. All lesions were localised intra-operatively with no peri-operative complications.

Conclusions

USGW localisation is a safe and effective pre-operative technique for the identification of small non-palpable head and neck tumours.

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.

Identification of Recurrent TERT Promoter Mutations in Intrathyroid Thymic Carcinomas

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

Carcinoma Showing Thymus-Like Differentiation (CASTLE) Arising in the Sublingual Gland

Carcinoma showing thymic-like differentiation (CASTLE) is a rare tumor most commonly occurring in the thyroid and soft tissues of the neck. We report the first case of CASTLE occurring in the sublingual gland. The patient, a 35-year-old healthy man, presented with a submucosal lesion located in the anterior right floor of the oral cavity and an ipsilateral neck mass. The lesion had been previously investigated by neck computed tomography and ultrasound-guided fine needle aspiration cytology and diagnosed as metastatic squamous cell carcinoma. After oral cavity magnetic resonance imaging, positron emission tomography, and a non-diriment, fine needle aspiration cytology of the sublingual mass, the patient was treated as affected by a sublingual gland malignancy with removal of primary tumor and neck dissection. Morphological and immunohistochemical findings were diagnostic for primary sublingual gland CASTLE. The patient received adjuvant radiotherapy and is free of disease 2 years after treatment. We describe the pathological features of the lesion and discuss the possible differential diagnoses.

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.

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.

[BRAF-positive paucicellular variant of anaplastic carcinoma in the presence of tall cell variant papillary thyroid cancer]

To paper describes a case of paucicellular anaplastic cancer in the presence of tall cell variant papillary thyroid carcinoma. Microscopic examination showed that the differentiated component of the tumor was composed of papillary structures with tall cells, the height of which exceeded 3-4 times the width. Its anaplastic component consisted of fibrous tissue with occasional spindle-shaped cells and focal lymphocytic infiltration to the extent of 70%. The spindle-shaped cells expressed cytokeratins, β-catenin, p53, and vimentin. The tumor cells and lymphocytes showed an association with Epstein-Barr virus. Molecular genetic study of the tumor revealed the following mutations: BRAF p.Val600Glu (p.V600e was), HRAS p.His27His (p.H27H), PIK3CA p.Glu545Lys (p.E545K), TP53 p.Arg248Gln (p.R248Q).

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.

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

BACKGROUND

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

PATIENT

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

SUMMARY

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

CONCLUSION

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

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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.

Sonographic findings in three cases of carcinoma showing thymus-like differentiation

Carcinoma showing thymus-like differentiation (CASTLE) is a rare tumor of the thyroid gland or soft tissues of the head and neck. To our knowledge, there have been only a few reports concerning imaging findings of CASTLE. We report herein the sonographic appearances of three cases of CASTLE. Two tumors were located at the lower part of the thyroid and one had spread throughout the thyroid. Sonograms showed heterogeneously solid tumors without cystic components or calcification. The central part of the tumor was slightly hyperechoic compared with the peripheral part of the tumor. Histologically, the tumors were composed of a mixture of fibrous stroma and epithelial nests.

Cytologic Findings of Thyroid Carcinoma Showing Thymus-like Differentiation: A Case Report

Carcinoma showing thymus-like differentiation (CASTLE) is a rare carcinoma of the thyroid or adjacent soft tissue of the neck with a histologic resemblance to thymic epithelial tumors. Although the fine-needle aspiration (FNA) plays a central role in the initial evaluation of thyroid nodules, few reports about the cytologic findings of CASTLE have been found according to a review of literatures. We report cytologic findings of a case of CASTLE. A 34-year-old woman presented with a 2-month history of sore throat. The FNA showed that the smear was composed of three dimensional clusters and sheets. The tumor cells were round to ovoid with high nuclear : cytoplasmic ratios. The nuclei were vesicular with small nucleoli. There were some tumor cells showing keratinization. Some lymphocytes were found on the background and within clusters. The presence of poorly-differentiated tumor cells with a focal keratinization and a lymphocytic background on the FNA is suggestive of CASTLE.

A technical note: pre-operative ultrasound-guided wire localization in head and neck surgery

Ultrasound-guided wire localization of impalpable lesions is a well-recognized technique in the management of breast pathology, but its use in the head and neck is not well described. Performed under local anesthesia, high-resolution ultrasound provides real-time imaging for accurate placement of the wire resulting in fewer complications. Wire localization can focus the surgical approach, which reduces operating time and minimizes trauma to surrounding tissues. In this technical note, we describe two cases of pre-operative ultrasound-guided wire localization to facilitate the surgical excision of impalpable neck lesions.

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.