This case closely resembles sarcoidosis at low
magnification due to prominent aggregates of histiocytes; however,
the granulomas in sarcoidosis are usually more well-defined and
compact. Another differential diagnosis is Lennert lymphoma. With
the differential diagnosis in mind, careful searching for Hodgkin
cells/RS cells or atypical lymphocytes at high-power is the key.
An important personal
lesion: we often need to think outside the box, not just
focusing on the "major" or "obvious" lesions on the slides. Also
need to pay attention to the background, where the real pathology
changes hide occasionally.