Ectopic hamartomatous thymoma: a clinicopathological and immunohistochemical study of two cases / 中华病理学杂志
Chinese Journal of Pathology
;
(12): 397-401, 2005.
Article
in Chinese
| WPRIM
| ID: wpr-297338
ABSTRACT
<p><b>OBJECTIVE</b>To study the clinicopathological and immunohistochemical features of ectopic hamartomatous thymoma (EHT), and to discuss its histogenesis.</p><p><b>METHODS</b>The clinical and pathologic features of two EHT cases of were evaluated. Immunohistochemical study was performed by LSAB method using a panel of antibodies including AE1/AE3, CK5, CK7, CK8, CK20, EMA, vimentin, CD5, CD10, alpha-SMA, calponin, desmin, CD34, S-100 protein, CD57, GFAP, TTF-1 and CD99.</p><p><b>RESULTS</b>Both cases occurred in males aged 20 years and 40 years respectively. Each patient presented with a solitary mass, one located in the suprasternal fossa and the other in the left supraclavicular region for a period of 6 months and 2 months respectively. Grossly, the masses were well-circumscribed with spherical and ovoid appearance, measuring 5 cm and 3 cm in maximum diameter respectively. On cut section, they were gray-white in color and of soft consistency. Histologically, both tumors were composed of a mixture of spindle cells, epithelial cells and mature adipose tissue. The spindle cells element accounted 85% and 70% each in the two cases. They resembled fibroblasts in morphology and were arranged frequently in fascicular, woven or storiform patterns. Epithelial cells element represented nearly 10% in both cases. Most of the epithelial cells had a non-keratinization squamous appearance. They formed small solid islands and adamantinoma-like "nastomosing cords", or appeared as lining cells in large cystic spaces. In focal areas, glandular differentiation presented as small glands. A transition between the spindle cell and epithelium components could be also identified in some areas. Mature adipose tissue was irregularly distributed in the two tumors, about < 5% and 20% respectively. Immunohistochemically, the epithelial element expressed AE1/AE3, CK5, CK7, CK8 and EMA, whereas the spindle component expressed AE1/AE3, CK5, CK7, CK8, vimentin, CD10, CD34, alpha-SMA, MSA, and calponin. Both elements were negative for CK20, TTF-1, desmin, S-100 protein, CD57, GFAP and CD99.</p><p><b>CONCLUSIONS</b>EHT is a benign tumor that occurs predominantly in the lower neck region of young to middle-aged males. Immunohistochemical study revealed myoepithelial differentiation of the spindle cells, suggesting EHT is a mixed tumor composed of epithelial and myoepithelial cells. EHT possibly originates from the remnants of cervical sinus of His, and therefore, may be renamed as branchial anlage mixed tumor.</p>
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Pathology
/
General Surgery
/
Thymoma
/
Thymus Neoplasms
/
Vimentin
/
Anion Exchange Protein 1, Erythrocyte
/
Choristoma
/
Mucin-1
/
Diagnosis, Differential
/
Keratins, Type II
Type of study:
Diagnostic study
Limits:
Adult
/
Humans
/
Male
Language:
Chinese
Journal:
Chinese Journal of Pathology
Year:
2005
Type:
Article
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