Aberrant synaptophysin expression in classic Hodgkin lymphoma

Area of Science:

• Oncology
• Pathology
• Immunohistochemistry

Background:

• Synaptophysin is a standard immunohistochemical marker for neuroendocrine differentiation and diagnosis.
• Its expression in malignant lymphoma has not been previously described.
• This study was prompted by an observation of synaptophysin expression in a case of classic Hodgkin lymphoma.

Purpose of the Study:

• To investigate the expression of synaptophysin in classic Hodgkin lymphoma.
• To determine the frequency of synaptophysin expression in various lymphoma subtypes.

Main Methods:

• Immunohistochemical staining for synaptophysin was performed on 59 cases of classic Hodgkin lymphoma and other lymphoma types.
• Synaptophysin-positive cases were further stained for chromogranin and CD56a.

Main Results:

• Synaptophysin was expressed in 11 out of 59 (19%) classic Hodgkin lymphoma cases.
• Expression was weak but specific to the cytoplasm of tumor cells, with no expression in background inflammatory cells.
• Anaplastic large cell lymphomas, diffuse large B-cell lymphomas, and extranodal marginal zone lymphomas did not express synaptophysin.
• Synaptophysin-positive classic Hodgkin lymphomas did not express chromogranin or CD56a.

Conclusions:

• Aberrant synaptophysin expression is an unexpectedly frequent finding in classic Hodgkin lymphoma.
• The mechanism and prognostic significance of this aberrant expression remain unclear.
• Synaptophysin positivity in lymphoma can be a diagnostic pitfall, especially in small biopsies.