College of American Pathologists

2014 — April Case of the Month

Posted April 8, 2014


CAP Foundation Online Case of the Month

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A 70-year-old woman presented with increasing shortness of breath of several weeks duration. Further work-up revealed a large mass located in the thymus, which was surgically resected. The resected mass weighed 144 g, measured 21.0 cm in greatest dimension and on sectioning had a predominantly uniform tan appearance with focal areas of calcifications. The light microscopic appearance of the mass prompted immunohistochemical studies and the pertinent results are as follows: The lesional cells were negative for cytokeratin AE1/AE3, CK19, p63, CD5 and CD117. They showed focal cytoplasmic staining for CD21and strong positivity for CD35 and D2-40.

The master list with the correct answer

  • Follicular dendritic cell sarcoma
  • Nodular sclerosis classical Hodgkin lymphoma
  • Primary mediastinal large B-cell lymphoma
  • Spindle cell thymoma
  • Thymic carcinoma (spindle cell variant)

Access Case Critique to view:

  • Appropriate diagnosis
  • Critique
  • References

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