Abscess of the spleen is a very rare lesion. In this study, 4 cases of splenic abscess are presented and discussed along with the literature. The cases were between 16 and 55 years-old and two of them had hematologic malignancy. All of them had been operated on because of acute abdomen, and in two cases splenic rupture was present. Only in one of the cases was salmonellosis detected by microbiological methods. By histological examination, expansion and congestion in splenic sinusoids, and foci of abscess including wide areas of necrosis and inflammatory infiltration by neutrophils were seen in all cases. The most frequent cause of splenic abscess is septic embolism arising from bacterial endocarditis. There are also a few splenic abscess cases seen with malignancies. While splenic abscess is seen rarely, it has a high rate of mortality when it is diagnosed late.

A 45-year-old woman presented with complaints of low back pain and sciatica on the left persisting for 2 years. She had undergone left hemilaminectomy and discectomy for L4-5 intervertebral disc herniation at another medical center. Spinal computed tomography and magnetic resonance (MR) imaging revealed a mass lesion in the posterior paravertebral region. The mass was hypointense with ring enhancement on the T 1 -weighted images and hyperintense on the T 2 -weighted images. Surgery found a retained sponge within the paraspinal mass cavity which was removed totally. Foreign-body granuloma (``gauzoma'') induced by forgotten sponge material is not an unusual complication of posterior lumbar surgery and should be considered as a potential cause in cases of surgical wound infections. MR imaging is essential to achieve the correct differential diagnosis.

Pulmonary involvement is a serious complication of rheumatoid arthritis (RA) and may be seen as airway disease, rheumatoid nodules, interstitial lung disease, and pleurisy. However, cavitary rheumatoid nodules without articular manifestations are rare. We describe a male patient presenting with pleurisy and multiple rheumatoid necrobiotic nodules in the absence of arthritis or subcutaneous nodules. One of the nodules was quite large (5 x 8 cm in diameter) and cavitary, imitating bronchial carcinoma radiologically and bronchoscopically. Definite histopathologic diagnosis was obtained by open lung biopsy. The patient was given methylprednisolone and methotrexate, and significant regression was observed in clinical and radiologic findings. He has been followed for 14 months with no articular manifestations yet, receiving 4 mg/d methylprednisolone and 20 mg/wk methotrexate. The diagnosis of rheumatoid pulmonary involvement without articular manifestations can be difficult. Rheumatoid nodules may imitate bronchial carcinoma, or bronchial carcinoma may coexist in RA patients. Open lung biopsy may be necessary for differential diagnosis of pulmonary lesions in RA.

A mediastinal mass was found in a 37 year old male who presented with fever, weight loss and fatigue. The chest CT revealed a 9x6x4 cm well circumscribed mass located paratrachaelly in the upper mid-mediastinum. The mass was removed by right thoracotomy. Macroscopically the tumor weighed 195 g and measured 9x6x4 cm. Microscopically the tumor consisted of small blue cells in solid and trabecular pattern. Immunohistochemical studies performed for differential diagnosis of small blue cell tumors. The tumor was diagnosed as primary neuroendocrine carcinoma of the mediastinum. This case is presented for its rare recurrence in that particular location.

HP infection increases the proliferative rate of gastric foveolar cells in conjunction with an increased apoptotic rate and activation of MAPK(ERK). MAPK activation seems to be a significant and persistent event in the HP-induced neoplastic transformation.