Clinical features:
(1) The patient has a long-standing chronic inflammatory process that involves a closed space, usually for 10 years or more.
(2) The patent develops a mass at the site of the inflammation.
(3) The tumor is often aggressive.
Sites where tumors have developed:
(1) pleural cavity (see previous section)
(2) chronic osteomyelitis
(3) metallic joint implant
(4) surgical mesh
(5) hydrocele
(6) chronic venous ulcer
(7) chronic cyst (splenic, pancreatic, thyroid, etc)
Laboratory findings:
(1) The histology usually shows a diffuse large B cell lymphoma (DLBCL).
(2) There is often evidence of Epstein-Barr virus (EBV), including positive ISH.
Poor prognostic features:
(1) Stage III or IV
(2) poor performance status (ECOG 2 to 4)
(3) elevated serum LDH
Favorable features:
(1) complete resection
(2) good response to chemoradiation
