A 79yrold woman with bilateral ptosis and neck muscle weakness

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A 79-yr-old woman with bilateral ptosis and neck
muscle weakness

• Brief Hx and course
• 1MA left ptosis
• 3MA neck muscle weakness
• 1WA right ptosis, diplopia
• Jolly test right orbicularis oculi, trapezius??
  decremental response ()
• A small soft tissue nodule in the anterior
  mediastinum

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A small soft tissue nodule in the anterior
mediastinum
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A ovoid thymic mass with well demarcated margin
After formalin fixation
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Lobular growth pattern and infiltration into
mediastinal fat
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Infiltration into mediastinal fat
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Infiltration into mediastinal fat across the
fibrous capsule
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Type B3 Thymoma
Type B3 thymoma is an organotypic thymic
epithelial tumor predominantly composed of
medium-sized round or polygonal cells with slight
atypia. The epithelial cells are mixed with a
minor component of intraepithelial lymphocytes,
resulting in a sheet-like growth of epithelial
cells.