Histological verification of positive positron emission tomography findings in the follow-up of patients with mediastinal lymphoma.
OBJECTIVE
Follow-ups of patients with mediastinal lymphoma are not accurate if they rely on computed tomography (CT). Positron emission tomography (PET) has been suggested to be useful in several lymphoma settings, such as initial staging, evaluation of residual masses after therapy, and assessment of response early in the course of treatment. The aim of this retrospective study was to verify the reliability of positive PET scans of the mediastinum in following up patients with mediastinal lymphoma, using histological findings as a comparison.


METHODS
From January 2002 to July 2005, 151 patients with mediastinal lymphoma (57 with Hodgkin's disease [HD] and 94 with aggressive non-Hodgkin's lymphoma [NHL]) were followed-up after the end of front-line treatment. Patients with a positive PET scan of the mediastinum underwent CT scanning and surgical biopsy.


RESULTS
In 30 (21 HD and 9 NHL) out of 151 patients (20%) a suspicion of lymphoma relapse was raised based on positive mediastinal PET scanning. Histology confirmed this suspicion in 17 (10 HD and 7 NHL) out of 30 patients (57%), whereas either benign (9 fibrosis, 3 sarcoid-like granulomatosis) or unrelated neoplastic conditions (1 thymoma) were demonstrated in the remaining 13 patients (43%). SUVmax was significantly higher among patients who had signs of relapse (17 true positive cases) than among those who stayed in remission (13 false positive cases), the median values being 5.95 (range, 3.5-26.9) and 2.90 (range, 1.4-3.3), respectively (p=0.01).


CONCLUSIONS
We suggest that a positive PET scan of the mediastinum of a patient being followed-up for a mediastinal lymphoma should not be considered sufficient for diagnostic purposes in view of its lack of discrimination. Histological confirmation can safely be carried out with various biopsy techniques, the choice of which should be made on the basis of the findings of the clinical and imaging studies of the individual case.
Zinzani
Pier Luigi
PL
Institute of Hematology and Oncology L. and A. Seràgnoli, University of Bologna, Bologna, Italy. plzinzo@med.unibo.it
Tani
Monica
M
Trisolini
Rocco
R
Fanti
Stefano
S
Stefoni
Vittorio
V
Alifano
Marco
M
Castellucci
Paolo
P
Musuraca
Gerardo
G
Dalpiaz
Giorgia
G
Alinari
Lapo
L
Marchi
Enrica
E
Fina
Mariapaola
M
Pellegrini
Cinzia
C
Farsad
Mohsen
M
Cancellieri
Alessandra
A
Busca
Annalisa
A
Canini
Romeo
R
Pileri
Stefano
S
Baccarani
Michele
M
Boaron
Maurizio
M
D000293:Adolescent; D000328:Adult; D003951:Diagnostic Errors; D005500:Follow-Up Studies; D006653:Histology; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000175:diagnosis*; D008479:Mediastinal Neoplasms / Q000175:diagnosis*; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000592:standards*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed