Fig. 3

Microscopic findings of the present right tumor and previous left tumor. HE staining of the present right tumor mostly showed an alveolar growth pattern (× 100; a) with cells composed clear cytoplasm (× 100; b). Very large tumor cells (× 100; c) and a papillary growth pattern (× 100; d) were focally observed. Moderate to strong immunostaining of TFE3 in the nuclei of tumor cells was seen (× 200; e). HE staining of the previous left tumor showed an alveolar growth pattern (× 100; f), pale eosinophilic cytoplasm (× 100; g) and very large tumor cells (× 100; h). Dedifferentiated sarcomatoid features were partially observed (× 100; i). Moderate to strong immunostaining of TFE3 in the nuclei of tumor cells was seen (× 200; j)