This entity should be considered in the list of differential diagnoses for gastrointestinal stromal tumour. The lymph node metastasis and immunohistochemical features are of value for identification of this rare neoplasm.

A 14-year old girl with lupus erythematosus (LE) who initially showed as discoid lupus and followed with nephrotic syndrome one year later. Concomitant piroxicam and indomethacin were prescribed for her arthritis, which preceded two months before the onset of nephrotic syndrome. Histology from renal biopsy showed minimal-change nephrotic syndrome (MCNS). After continuous treatment for six months, nephrotic syndrome resolved completely and no signs of relapse were noted over 14 years of follow-up. For the children, it is rare to have both LE and MCNS simultaneously; sequela of nonsteroidal anti-inflammatory drugs also seldom results in nephrotic syndrome. Though their relationship is still not defined, the possibility of LE combined with MCNS must be differentiated in patients with lupus and severe proteinuria.

The STAT3 (signal transducers and activators of transcription 3) signalling pathway plays a pivotal role in oncogenesis and appears essential for postnatal maintenance of thymic architecture and thymocyte survival. The association of STAT3 activation with thymic epithelial tumours (TETs) and myasthenia gravis (MG) has not been elucidated. In this study, 118 cases of TET and 25 non-neoplastic thymic tissue samples were evaluated for STAT3 and phospho-STAT3 (pSTAT3) expression immunohistochemically. In addition, 44 normal thymuses of different ages were included for comparison. It was found that STAT3 activation in thymic epithelial cells (TECs), as evidenced by pSTAT3 expression and/or nuclear STAT3, was present in the majority of non-neoplastic thymuses (88%, 22/25), including those from young children, but not in fetal thymus. In thymoma (n = 73), activated STAT3 was noted at a significantly higher frequency in the cases of lymphocyte-rich thymoma (ie types AB, B1, and B2, 46%, 23/50) in comparison with lymphocyte-depleted thymoma (types A and B3, 1/23) (p = 0.009). Thymoma with activated STAT3 tended to present at an earlier stage, show complete resectability and less aggressive behaviour, and have a higher correlation with MG than the STAT3-negative/inactive group (p < 0.05). In contrast, thymic carcinoma with activated STAT3 (14/45, 31%) had significantly higher rates of unresectability, vascular invasion, and regional lymph node metastasis (p < 0.05). These data provide the first evidence that constitutive STAT3 activation is seen in both benign and neoplastic thymic tissue and is associated with the persistence of thymic tissue and the presence of MG. It is likely to be induced by different factors in thymoma and thymic carcinoma.