Aspiration cytology of an enlarged thymus presenting as a mediastinal mass. A case report
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Examination of Thymic Positive and Negative Selection by Flow Cytometry
Published on: October 8, 2012
1Department of Pathology, Beheshti Hospital, Shiraz Medical School, Iran.
Insights
Fine needle aspiration (FNA) cytology of an anterior mediastinal mass in a child revealed features mimicking thymoma. However, the mass was a normal thymus, suggesting unique cytologic features for differentiation.
Area of Science:
- Pathology
- Cytopathology
- Pediatric Oncology
Background:
- Anterior mediastinal masses require accurate diagnosis.
- Fine needle aspiration (FNA) cytology is a key diagnostic tool.
- Differentiating thymoma from thymic hyperplasia is crucial in pediatric cases.
Observation:
- A 12-year-old girl presented with an anterior mediastinal mass.
- FNA cytology showed epithelial cells and lymphocytes, resembling thymoma.
- Histopathology confirmed the mass as an enlarged, normal thymus.
Findings:
- Cytologic features in the FNA smears, including varied epithelial cell nuclei and surrounding lymphocytes, were atypical for thymoma.
- These distinct features may help differentiate thymic hyperplasia from thymoma on FNA.
Implications:
- Further studies are needed to establish definitive FNA cytologic criteria for distinguishing thymoma from thymic hyperplasia.
- Accurate cytologic differentiation can guide appropriate clinical management and avoid unnecessary invasive procedures.
Abstract:
Fine needle aspiration (FNA) cytology was used to evaluate an anterior mediastinal mass in a 12-year-old girl. The smears showed two cellular populations composed of epithelial cells and many lymphocytes, simulating FNA cytologic features of a thymoma. However, histopathologically the mass proved to be an enlarged and microscopically normal thymus. The different shapes and sizes of the epithelial cell nuclei and lymphocytes encircling the individual epithelial cells present in the FNA smears of the enlarged thymus were features that are not seen frequently in FNA smears of thymomas and therefore may be differentiating points. However, studies of FNA smears from more cases of thymoma and thymic hyperplasia are necessary in order to define FNA cytologic criteria to differentiate these two entities.
