PMC5356291_01
(A): Ultrasonographic appearance of the thymoma at presentation. (B): Histopathological features of the clear cell thymoma showing the characteristic large round cells with abundant clear cytoplasm (H&E, original magnification x 10). (C): An ultrasound guided ECT session. (D): The ultrasonographic appearance of the needle array (arrow). (E): The tumor after two sessions of ECT, note the replacement of solid areas by cystic formations. (F): The histopathological appearance of the thymoma after ECT, showing partial replacement of neoplastic tissue by necrotic and fibrotic tissue (arrow) (H&E, original magnification x 5).
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F1
Moreover the mass was associated with compression of the adjacent organs and a significant pleural effusion (200 ml) that needed repeated tapping every five to seven days (Fig. 1A). The histopathology report came back with a diagnosis of clear cell thymoma. This is an unusual variant characterized by large round cells with abundant clear cytoplasm and distinct cytoplasmic margins (Fig. 1B) (Mackey, 1975; Mettler and Hauser, 1984). Five minutes after the injection, five trains of 8 biphasic pulses at the voltage of 800 V/cm, 1 Hz frequency, lasting 50 + 50 micros with 300 micros interpulse (total treatment time per train 3.2 ms) were administered by means of a clinical electroporator certified for veterinary application (Onkodisruptor , Biopulse S.r.l., Naples, Italy) using a specially paired needle array electrodes (Patent application EP2221086A1) until complete coverage of the lesion was achieved (Fig. 1C). This electrode has a specially devised nonconductive shielding that leaves as active parts the final 1.5 cm of the needles and is ultrasonographically detectable (Fig. 1D). After two additional weeks ultrasonography evidenced a 50% tumor reduction (major diameter 3.5 cm) with the formation of larger cystic areas (Fig. 1E). Histopathology exam evidenced the replacing of large areas of tumor by necrotic and sclerotic tissue, consistent with response to ECT (Fig. 1F) (Spugnini et al., 2007).