Case Of Ectopic Hamartomatous Thymoma Research Articles

Ectopic Hamartomatous Thymoma-New Insights Into a Challenging Entity: A Clinicopathologic and Immunohistochemical Study of 9 Cases.

Nine cases of ectopic hamartomatous thymoma are described. The patients were 5 men and 4 women aged 34 to 52 years (mean, 43 y). All patients presented with solitary lower neck masses ranging in size from 3.5 to 8.0 cm (mean, 5.4 cm). Grossly, the lesions were circumscribed and lobulated masses with a fleshy white cut surface; cystic changes were identified in 3 cases. Histologically, the tumors were composed of varying proportions of spindle cells arranged in fascicles, mature adipose tissue, and an epithelial component composed of squamoid elements and glandular or ductal structures. In 1 case, duct-like structures dominated the histologic picture. Structures reminiscent of Hassall corpuscles were identified in 2 cases. No overt malignant changes were seen, and the mitotic activity ranged from 0 to 2 mitoses per 10 high-power fields. Immunohistochemically, the spindle cells coexpressed CK5/6, CD34, and smooth muscle actin, whereas the squamous component was positive for CK5/6 only. Bcl-2 was variably expressed in the spindle and epithelial elements, whereas Pax8 and STAT6 were uniformly negative. Clinical follow-up revealed that all patients were alive and well 2 to 5 years after diagnosis. Ectopic hamartomatous thymomas are benign neoplasms with a wide morphologic spectrum. The histologic and immunohistochemical features are reminiscent of thymic derivation and suggest possible origin from remnants of the thymic anlage. Changes in the nomenclature may be advised to more specifically designate tumor differentiation and to avoid confusion with true thymomas as these represent entirely separate clinicopathologic entities.

An ectopic hamartomatous thymoma compressing left jugular vein.

Ectopic hamartomatous thymoma (EHT) is an extremely rare benign neoplasm. It is usually found at the root of the neck (frequently on the left) and does not usually impact adjacent tissues in clinically significant ways. While EHT manifests distinct pathological features, the lesion is either asymptomatic or may show nonspecific clinical features. We report one case of EHT which was assumed to be of low malignant potential since it severely compressed the inlet of left internal jugular vein as seen by computed tomography scan. To the best of our knowledge, this clinical finding of EHT is very rare. After the diagnosis and treatment of this patient, we believe that EHT or suspected EHT should be treated less invasively.

A Case of Ectopic Hamartomatous Thymoma

Ectopic hamartomatous thymoma (EHT) is a rare and distinctive benign tumor that usually occurs in the supraclavicular, suprasternal areas. Histopathologically, it is characterized by a mixture of spindle cells, epithelial cells, and adipose cell elements. The recognition of EHT and differentiation of it from high-grade sarcomas such as synovial sarcoma is important, because EHT follows a benign clinical course and conservative surgical excision is the treatment of choice. We experienced a case of EHT in the supraclavicular area, so we present the case with a review of the related literatures.� Korean J Otorhinolaryngol-Head Neck Surg 2013;56:778-80 Key WordsZZEctopic hamartomatous thymoma ㆍSarcoma.

Ectopic hamartomatous thymoma: a case demonstrating skin adnexal differentiation with positivity for epithelial membrane antigen, androgen receptors, and BRST-2 by immunohistochemistry

Ectopic hamartomatous thymoma is a rare tumor of the lower neck occurring in adult men, which follows a benign course. They are triphasic with epithelial, adipocytic, and spindled elements in variable amounts. The origin of this tumor has been debated, but it is now believed to arise from remnants of the cervical sinus of His from early development. We describe a case of ectopic hamartomatous thymoma with typical features, as well as multifocal areas of skin adnexal differentiation. These included sebaceous, eccrine, and apocrine elements. We highlighted these by using immunohistochemistry to epithelial membrane antigen, BRST-2, and androgen receptors (AR). Epithelial membrane antigen stained sebaceous cells and the luminal borders of eccrine and apocrine ducts. BRST-2 and AR stained apocrine elements in a cytoplasmic and a nuclear pattern, respectively. The spindled component also expressed nuclear AR. AR positivity has not been described previously and may explain the occurrence primarily in men in postpubertal life.

Ectopic hamartomatous thymoma: a case report with immunohistochemical study and review of the literature

Ectopic hamartomatous thymoma (EHT) is a rare benign tumor. We present a case of EHT, which was seen as subcutaneous mass on the left supraclavicular area in a 19-year-old man. The tumor consisted of spindle cells, epithelial cells, adipose cells, and a small amount of lymphocytes, as described previously. Immunohistochemically, spindle cells were positive for keratin, a-smooth muscle actin, CD34 and vimentin, but negative for desmin and S-100 protein. Lymphocytes were positive for CD45RO but negative for CD20, CD1a, and CD99. Approximately, 5% of cells were positive for MIB-1 and no cells stained for p53 and bcl-2. Recognition of EHT is important and needs to be differentiated from high-grade sarcomas such as synovial sarcoma or glandular malignant peripheral nerve sheath tumor.

Ectopic hamartomatous thymoma: Clinicopathologic, immunohistochemical, and histogenetic considerations in four new cases

Four new cases of ectopic hamartomatous thymoma are presented. The tumor occurred either superficially or deep in the area of the sternoclavicular joint and consisted of solid islands of squamous epithelium which blended with spindled cells. Cysts lined by squamous epithelium, small glands, and fat also occurred in variable amounts. Both the spindled and epithelial regions of the tumor expressed keratin and muscle actin, but neither desmin nor S100 protein. The tumor probably originates from thymic analage associated with the third pharyngeal pouch (thymus III), although origin from other structures such as thymus IV and the cervical sinus of His are discussed. Our experience indicates that the large size and extreme cellularity of the spindled portion of some tumors may result in the mistaken diagnosis of sarcoma.