What is the best initial diagnostic test for a suspected case of Hodgkin lymphoma?

The best initial diagnostic test for a suspected case of Hodgkin lymphoma is a lymph node excisional biopsy. This procedure involves the complete removal of an entire lymph node, which allows for a comprehensive evaluation of the tissue. In the context of Hodgkin lymphoma, histopathological examination is crucial due to the specific characteristics of Reed-Sternberg cells that confirm the diagnosis.

Excisional biopsy provides not only the necessary tissue for diagnosis but also a representative sample that can indicate the presence and type of lymphoma. This is vital because Hodgkin lymphoma has distinctive features that are best assessed through this method, including cellular morphology and immunochemistry, which may influence staging and treatment decisions.

Other diagnostic tests such as imaging (like a CT scan) or fine needle aspiration are valuable in different contexts. However, they do not offer the definitive histological confirmation needed to diagnose Hodgkin lymphoma accurately. Imagery may suggest lymphadenopathy or other structural abnormalities, but without the histopathological confirmation from a biopsy, one cannot establish a definitive diagnosis. Fine needle aspiration, while less invasive, usually does not provide adequate tissue for a conclusive diagnosis in cases of lymphoma due to its limited sampling capabilities.