Imaging wise, this looks like a lymphoma. Biopsy and IHC is required. As per PETCT there are neck lymph nodes. Excision biopsy of this lymph nodes is to be done and send for histopathology + IHC. Once lymphoma and the type is certain, we can discuss treatment options.
Next Steps
If in Bangalore, come to Vydehi. We will coordinate and get biopsy done