J Lung Cancer.  2011 Jun;10(1):56-58. 10.6058/jlc.2011.10.1.56.

Micronodular Thymoma with Lymphoid Stroma: A Case Report

• Song HJ
• Han J
• Kim TS

• KMID: 2199896
• DOI: http://doi.org/10.6058/jlc.2011.10.1.56

Abstract

Micronodular thymoma with lymphoid stroma (MNT) is an extremely rare tumor and has not been reported in Korea. Herein, we report a case of MNT diagnosed in a 75 year-old male. The mass was incidentally identified on thoracic computer tomography (CT) during work-up for a cardiac mass. The resected thymic mass was ovoid and solid measuring 3.5x3 cm in size and showed homogenously white tan, solid and firm cut surface. Microscopically, the tumor had a thin fibrous capsule except small foci of invasion to thymic adipose tissue, and consisted of characteristic multiple discrete epithelial nodules in abundant lymphoid stroma. The epithelial nests anastomosed each other, forming a vague cord-like structure. The cells in the epithelial nests were bland, spindle to oval shape with relatively abundant cytoplasm, slightly vesicular chromatin and one definite nucleolus. The lymphoid stroma contained prominent germinal centers. No evidence of recurrence or metastasis has been found within 4 years of surgery.

Keyword

Thymoma

MeSH Terms

Adipose Tissue
Chromatin
Cytoplasm
Germinal Center
Humans
Korea
Male
Neoplasm Metastasis
Recurrence
Thymoma
Triacetoneamine-N-Oxyl
Chromatin
Triacetoneamine-N-Oxyl

Figure

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  Fig. 1. (A) A well-demarcated mass (arrow) was found in the anterior mediastinum on thoracic computer tomography (CT). (B) Cut section of the mass was solid and lobulated with fine fibrous septa. (C) The tumor showed focal extension beyond the capsule to peri-thymic adipose tissue (hematoxylin-eosin stain, ×40). (D) Multiple lymphoid follicles with germinal centers were found in the lymphoid stroma (hematoxylin-eosin stain, ×200). (E) Discrete epithelial nodules in lymphoid-rich stroma were unique microscopic feature (hematoxylin-eosin stain, ×400). (F) Cytokeratin 5/6 was positive in the epithelial components, and CD 20 was positive in lymphoid stromal cells (inset) (ABC method, ×100).

Reference

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