RCPA Examinations in Anatomical pathology - Questions ... - Rcpa.tv

Case 15: Female 40 – right orbital
mass
• MICROSCOPIC
• The slide shows fibrous tissue infiltrated by a population of predominantly small lymphoid cells.
The cells are atypical and have slightly irregular nuclei with minimal m
discernible cytoplasm. There
are scattered larger cells with vesicular nuclei and small nucleoli. No follicular structures or
lymphoepithelial lesions can be identified.
• Comment
• The histologic appearance is that of a lymphoma. While this appears to be a small cell lymphoma
and the location in the orbit favours an extra nodal marginal zone lymphoma further
categorisation requires confirmation by flow cytometry and immunoperoxidase stains.
• Investigations
• Check if tissue has been submitted for flow cytometry and confirm m a monoclonal population
• Tissue for cytogenetics
• Immunoperoxidase stains CD20, CD79a, CD21 and possibly CD43 would d be expected the positive
in a MALT lymphoma and CD5, CD10 and Bcl6 would be expected to be negative. CD10 positivity
combined with Bcl2 positive staining would favour involvement by follicular lymphoma (however
no follicular structures can be identified in the slide examined) ) and positive staining for CD5 in
combination with cyclinD1 positivity would favour a Mantle cell lymphoma. If the lymphoma is
CD5 and CD23 positive small lymphocytic lymphoma is likely.
• SUMMARY
• Orbit: : Favour small B-cell B
lymphoma; await further characterization