Ectopic thymic carcinoma in the neck

Carcinoma showing thymus-like differentiation of the parotid gland: The brief report of cytomorphology and review of the literature

Here, we report an extremely rare case of carcinoma with thymus-like differentiation (CASTLE) of the parotid gland. CASTLE is a rare malignant epithelial tumor with thymic epithelial differentiation that arises in the thyroid gland or perithyroidal soft tissue. CASTLE of salivary gland origin is rare, with only nine published case reports to date (reported as "CASTLE" or "thymic carcinoma"). It is critical to diagnose salivary gland tumors using fine needle aspiration cytology. However, this tumor is rare, and there have been few studies on its cytomorphological features. Therefore, it is important to understand the cytological diagnostic characteristics of CASTLE. Herein, we review the cytological features and diagnostic characteristics of salivary gland CASTLE. We also report the genotype results obtained using targeted exome sequencing, which we analyzed with DNA extracted from formalin-fixed paraffin-embedded tissue.

Ectopic Thymic Carcinoma Located on The Dorsal Side of The Thyroid Gland

Migration of the embryonic thymus is thought to be the basis for the formation of ectopic thymic tumors. Thymic ectopy may be a result of the abnormal migration of the third or fourth branchial cleft to the anterior mediastinum during weeks 5–6 of embryonic development. However, ectopic thymic carcinoma has highly nonspecific histologic features and occurs in variable and unpredictable locations making it difficult to diagnose. However, the clinical diagnosis and treatment should not overlook the possibility of ectopic thymic tumors. Here, we report a case of ectopic thymic carcinoma diagnosed as thyroid cancer before surgery occurring in a location consistent with current assumptions. Furthermore, we briefly review the literature on ectopic thymic carcinoma and discuss current diagnostic and treatment approaches.

Ectopic cervical thymic squamous cell carcinoma misdiagnosed as thyroid cancer: a case report

Ectopic thymic neoplasm, particularly ectopic thymic carcinoma, is a rare disease that presents as a neck mass. Here, we present a case of ectopic thymic squamous carcinoma in a 65-year-old man who presented with persistent hoarseness. After fine needle aspiration cytology, the patient underwent total thyroidectomy with lymph node dissection. The final histopathological examination revealed the ectopic thymic squamous carcinoma. The patient was discharged without any postoperative complications. The patient received adjuvant radiation therapy and did not progress during the 1-year follow-up period.

[Ectopic thymic tissue and ectopic thymic tumors]

Ectopic thymic tissue outside its core position in the antero-superior mediastinum is quite common owing to the complexity of embryonal thymus development, whereby reported prevalence values (1 to 90%) are heavily dependent on the method of investigation and the intensity of the workup. The debated prevalence and relevance of ectopic thymic tissue and its accessibility underlie the ongoing discussion whether modern, minimally invasive thymectomy strategies can match the proven benefit of the radical transsternal thymectomy procedure for the treatment of Myasthenia gravis. In this context, the following article covers the etiology, prevalence, and location of normal-looking, reactive, and neoplastic ectopic thymic tissue. Furthermore, ectopic tissues and tumors inside or adjacent to the thymus are mentioned.

Ectopic right parietal pleural thymic carcinoma: a rare case and review of the literature

Ectopic thymic carcinoma is extremely rare. We present a case of a 73-year-old male patient with ectopic right parietal pleural thymic carcinoma and performed a literature review. Computed tomography (CT) of the chest demonstrated a sharp-edged soft tissue mass with intense enhancement measuring 47 mm × 29 mm with a broader base adjacent to the right axillary chest wall at the level of the 5th rib. There was no hilar or mediastinal lymphadenopathy or evidence of a mediastinal tumor or pleural nodules. A totally extra-pleural tumor resection and partial right lung resection was performed. Histological examination demonstrated infiltrative growth typical of carcinoma cells with a nest-like distribution locally invading the surface of the lung tissue. Immunohistochemical examination confirmed the diagnosis of thymic squamous carcinoma positive for CD5. Mediastinal radical radiotherapy (60 Gy) was performed postoperatively. The patient was followed for 17 months without any evidence of recurrence or metastasis.

Ectopic thymic carcinoma presenting as an intrathoracic mass

An asymptomatic 83-year-old man was found to have a right intrathoracic tumor. Computed tomography demonstrated a soft-tissue density mass measuring 55 × 25 × 22 mm adjacent to the right anterior chest wall. At surgery, the tumor was found to adhere to the diaphragm and right lung, contiguous with the mediastinal fat tissue. Histology of the resected specimen demonstrated proliferation of spindle and sarcomatous cells with multinucleated giant cells. Thus the tumor was diagnosed as undifferentiated thymic carcinoma and was considered to have arisen from ectopic thymic tissue. At 2 years postoperatively, the patient had no evidence of recurrence.

A rare case of ectopic laterocervical thymoma

The ectopic cervical thymoma is a rare site for a thymus neoplasm. It is frequently confused with cyst or with later neck mass of uncertain diagnosis until a histological diagnosis is made. Thymic neoplasms normally arise in the mediastinum, causing signs and symptoms of compression of the adjacent structures. Although rare, malignant thymomas may develop from an ectopic thymus, situated in the thyroid gland (Miyauchi et al., 1985; Matsuura et al., 2004), the neck (Yan et al., 2010; Yao et al., 2010; Jung et al., 1999), the lungs (Myers et al., 2007), and the heart (Miller et al., 2005). It is thought to be caused by the persistence of embryological organ portions along its route of physiological descent from the neck into the mediastinum during embryological development. The incidence of ectopic thymoma is around 4%. The thymus is a lympho-epithelial organ that is the centre of the development and maturation of the T lymphocytes. It develops from the ventral portion of the third and fourth pharyngeal pouches and by the sixth week of gestation it descends into the anterior mediastinum. It has a lobular structure with an external or cortical portion, richly populated by immature T cells, thymocyte and an internal medullary part.