Use of FDG PET/CT in Patients with Pancoast Tumors: Does It Add Any Contribution to Patient Management?

Ipsilateral Hyperhidrosis: Atypical Symptom of Small Lung Adenocarcinoma Evaluated by 18F-FDG PET-CT

A 45-year-old male visited our clinic due to right palmar anhidrosis and contralateral hyperhidrosis. Chest computed tomography (CT) showed a solitary pulmonary nodule with mediastinal lymph node enlargement, but a cause for atypical palmar anhidrosis was not identified. Subsequent fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed (PET/CT) revealed a localized pleural metastasis at the right apex with direct invasion of the paravertebral sympathetic chain. The pleural metastasis, which was not seen on chest CT, evoked ipsilateral anhidrosis independent of a mass effect or direct invasion by the primary lung tumor. ¹⁸F-FDG PET/CT can be helpful in identifying the cause of atypical symptoms in patient with small sized lung cancer.

Can metabolic tumor parameters on primary staging 18F-FDG PET/CT aid in risk stratification of primary central nervous system lymphomas for patient management as a prognostic model?

OBJECTIVE

Primary central nervous system (CNS) lymphoma is an aggressive and fatal extranodal non-Hodgkin lymphoma jailed in CNS at initial diagnosis. Its prognosis is poor and the disease has a fatal outcome when compared with systemic non-Hodgkin lymphoma. A few baseline risk stratification scoring systems have been suggested to estimate the prognosis mainly based on serum lactate dehydrogenase level,age, Karnofsky performance score, involvement of deep brain structures and cerebrospinal fluid protein concentration. ¹⁸F-FDG PET/CT has a high prognostic value with respect to overall survival and disease-free survival in many cancers and lymphomas. We aimed to investigate metabolic tumor indexes on primary staging ¹⁸F-FDG PET/CT as prognostic markers in primary CNS lymphoma.

MATERIAL AND METHODS

Fourteen patients with primary CNS diffuse large B-cell lymphoma (stage i) were enrolled in this retrospective cohort study. Primary staging ¹⁸F-FDG PET/CT was performed and quantitative parameters like maximum standardized uptake value, average standardized uptake value, metabolic tumor volume and total lesion glycolysis (TLG) were calculated for all patients before the treatment. Cox regression models were performed to determine their relation with survival time.

RESULTS

In the evaluation of all potential risk factors impacting recurrence/metastases (age, sex, serum lactate dehydrogenase, involvement of deep brain structures, maximum standardized uptake value, average standardized uptake value, metabolic tumor volume, and TLG) with univariate analysis, TLG remained statistically significant (P=.02).

CONCLUSION

Metabolic tumor parameters are useful in prognosis estimation of primary CNS lymphomas, especially TLG, which is the most important one and may play a role in patient management.