Trifon Spyridonidis

Erdheim-Chester disease : a rare syndrome with a characteristic bone scintigraphy pattern

Erdheim-Chester disease is a rare noninherited, non-Langerhans’ cell histiocytosis, with multiorgan involvement. The skeleton is frequently involved in as many as 70–80% of all cases. In nearly half of the cases, there is an involvement of other organs such as the cardiovascular system, lung, kidneys, brain, and orbits. Extra-skeletal involvement is correlated with increased morbidity and mortality. In recent years, the disease is being described with increasing frequency although fewer than 200 cases have been identified worldwide. Besides its rarity, the disease has a characteristic almost pathognomonic bone scan appearance, which in some cases facilitates diagnosis of the syndrome. Bone scans also contribute to the qualitative assessment of skeletal involvement.

(99m)Tc sestamibi as a prognostic factor of response to first-line therapy and outcome in patients with malignant lymphoma.

Introduction Resistance to chemotherapy poses a major problem in cancer patients. Although of multifactorial origin, some of the implicated mechanisms also interfere with 99mTc-MIBI uptake and retention in cancer cells. The aim of the current study was to investigate the prognostic value of baseline 99mTc-MIBI imaging in lymphoma. Methods 99mTc-MIBI SPECT was performed in 16 patients with Hodgkin lymphoma and 31 with non-Hodgkin lymphoma (NHL) before chemotherapy initiation. Early (20 minutes), late (120 minutes) tumor-to-background (T/B) ratios, and 2-hour 99mTc-MIBI washout were calculated. Follow-up data were obtained for a period of 45.5 ± 23.5 months. Study end points were response to first-line chemotherapy, lymphoma-related death (LRD), and time to disease progression. Results Of the scintigraphic indices examined, the late T/B ratio correlated best with study end points. A cutoff value of 1.8 determined by receiver operating characteristic analysis discriminated poor from good response and LRD from survival with an accuracy of 87% and 81%, respectively. Kaplan-Meier survivor functions separated by this cutoff differed significantly for both time to disease progression and LRD (P = 0.0001 and P = 0.0015). In the Cox proportional hazards model, the late T/B ratio proved to have an independent and incremental value over clinical prognostic factors (age, lymphoma type, Ann Arbor stage, lactate dehydrogenase levels) and, in NHL patients, over the international prognostic index. Patients with high international prognostic index score could be further stratified into different prognostic categories. Conclusion The current study indicates that baseline 99mTc-MIBI SPECT can provide useful prognostic information in patients with lymphoma, particularly NHL, regarding therapy response and final outcome.