We described two cases of malignant schwannoma arising in patients with von Recklinghausen's disease and examined the mast cells infiltrated into histologic sections. One of the two cases histologically revealed apparent mast cell infiltration in some areas of malignant schwannoma as well as in the benign neurofibroma. The malignant lesion demonstrated significantly increased percentages of degranulated mast cells over the benign lesion using FITC-avidin staining. In an electron microscopic study, mast cells in the malignant lesion displayed empty granules, piecemeal degranulation, and canaliculi structures suggesting activation. These findings were not observed in the benign lesion. The other patient histologically showed no mast cells in the malignant lesion, although the benign neurofibroma in the patient disclosed numerous mast cells. The first patient had neither recurrence nor distant metastasis. On the other hand, the second patient without mast cells in the histology had multiple distant metastases.

We describe a rare case of multiple, subcutaneous nocardial abscesses. A 67-year-old Japanese male with bullous pemphigoid was admitted to our hospital, and systemic prednisolone and double filtration plasmapheresis were administered. During the combination treatment, he noted a solitary subcutaneous nodule on the right upper arm. The lesions gradually increased in number and disseminated. The microbial diagnosis was thought to be a Nocardia species. Administration of combination chemotherapy with minocycline and diamino-diphenyl sulfone failed to eliminate the nodules completely, so he was treated with daily injection of amikacin sulfate into the nodules. The lesions dramatically responded to this therapy and resolved in four weeks.

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