PDF (5 MB) - Jurnalul de Chirurgie

176 Lucaciu OR. et al.Jurnalul de Chirurgie (Iaşi), 2013, Vol. 9, Nr. 2radiography. CT scan is the gold standardimaging procedure in patients with miasteniagravis. Thymic enlargement should bedetermined because most enlarged thymusglands on CT scan represent a thymoma. CTscanning with intravenous contrast dye ismandatory and shows the relationshipbetween thymoma and surrounding vascularstructures; it also defines the vascularitypattern and assists the surgeon to plan thesurgical procedure to completely remove thetumor [7].Positron emission tomography (PET)has proven to be invaluable in confirmingthe diagnosis of malignant invasivethymoma. Although CT may reveal evidenceof anterior mediastinal masses, PET scanshows the hypermetabolic activity, thus thesuspicion of malignancy. PET should beadded as a diagnosis method to help thesurgeon in determining the adequate stageand involvement of other structures [8].Preoperative histological diagnosis canbe achieved through biopsy bymediastinoscopy, thoracoscopy or CTguided transparietal biopsy [9].With reference to histology, there is noclear distinction between benign ormalignant thymoma. The trend of a benignor malignant thymoma is determined by itsinvasive character. Malignant thymomainvades the great vessels, lymphatics andadjacent areas of the mediastinum structures.The survival rate of people with invasivethymoma for a 15 year-period is 12.5% and47% for a person with non-invasivethymoma. Death usually occurs by cardiactamponade or other cardio-respiratorycomplications [10].Usually thymoma are classified usingMasaoka Staging System (Table I) [3].The histological type is also essentialfor the prognosis; so, for medullary andmixed thymoma the disease free survivalrate is 100% and decreased to 28% forthymic carcinoma (Table II) [4,5].Several reports from the literaturesuggest that benign or malignant thymomasare chemosensitive tumors. Potentialcandidates for chemotherapy includeapproximately one third of the patients withinvasive thymoma, metastasis and allpatients with stage IV disease. Fornasiero Aet al. [5] reported successful long-termsurvival following treatment with cisplatin +vincristine + doxorubicin +cyclophosphamide for invasive Thymomaincompletely resected or inoperable cases.Out of 32 patients, 90% have responded totherapy with a mean survival of 15 months.A study performed by the EuropeanOrganisation for Research and Treatment ofCancer reported that in 16 cases of patientswith recurrent or metastatic thymoma, wereobserved five complete remissions and fourpartial remissions. The median survival inthis study was 4.3 years. [11]Table I Masaoka Staging System of thymomas [3]Stage Definition TreatmentIIIIIIIVAIVBEncapsulated tumorwith no gross ormicroscopic invasionMacroscopic invasioninto the mediastinalfat or pleura orMicroscopic invasioninto the capsuleInvasion of thepericardium, greatvessels, or lungPleural or pericardialmetastatic spreadPleural or pericardialmetastatic spreadRT radiotherapy; CHT chmiothérapyR 0 surgicalexcisionR 0 surgicalexcision + RTR 0 surgicalexcision + RTSurgical debulking+ RT + CHTSurgical debulking+ RT + CHTTable II World Health Organization: thymoma pathologicclassification [4,5]Type Histologic Description DFS (%)A Medullary thymoma 100AB Mixed thymoma 100B1 Predominantly cortical thymoma 83B2 Cortical thymoma 83B3Well-differentiated thymiccarcinoma35C Thymic carcinoma 28DFS: 10 years Disease-Free Survival rateCase reports have documented the useof oral corticosteroids causing regression ofan invasive thymoma [12]. In one case, the