[A case of gastric follicular lymphoma with rapid deterioration and transformation].

A 79-year-old male patient underwent esophagogastroduodenoscopy, which revealed a reddish lesion, 10mm in diameter, presenting as a surface recess in the angular incisure. He was diagnosed with gastric follicular lymphoma. Positron emission tomography-computed tomography revealed metastasis to the mediastinal lymph node, although the tumor size was small.

Malignant peripheral nerve sheath tumor (MPNST) showing perineurial cell differentiation.

We report a malignant peripheral nerve sheath tumor (MPNST) showing the unusual immunohistochemical feature of epithelial membrane antigen (EMA) immunoreactivity in a 52-year-old man. The tumor, located in the left paravertebral muscles, was composed of both cellular and myxoid areas. Spindle-shaped tumor cells were arranged in longitudinal cell cords, in a storiform pattern, and in whorled structures.