Macrognathia secondary to dialysis-related renal osteodystrophy treated successfully by parathyroidectomy.

Renal osteodystrophy (ROD) is one of the most common complications affecting patients with chronic renal failure both before and after the initiation of maintenance dialysis, but macrognathia secondary to ROD is rare. Usually, enlarged jaws due to ROD do not return to their normal contours after the treatment of hyperparathyroidism. To the authors' knowledge, this article describes the second case of macrognathia secondary to dialysis-related ROD treated successfully by parathyroidectomy. Immunohistochemical study of the maxilla confirmed that parathyroidectomy could stop maladaptive parathyroid hormone stimulation, which leads not only to the formation of osteoblastic progenitors that become fibroblast-like cells but also to osteoclast formation.

Primary pulmonary primitive neuroectodermal tumor (PNET). A case report.

We describe a rare case of a primary primitive neuroectodermal tumor (PNET) in the lung of a 17-year-old girl. Grossly, the tumor, located in the right lower lobe, was relatively well-circumscribed and whitish to yellowish in color with scattered hemorrhagic necrosis. Microscopically, the tumor was composed of ovoid to polygonal cells with a high nuclear to cytoplasmic ratio and relatively scant cytoplasm, arranged in solid sheets with intervening fine fibrovascular stroma. Immunohistochemically, the tumor was positive for the MIC2 gene product, whereas AE1/AE3, CAM5.2, and a variety of neuroendocrine markers such as chromogranin A, synaptophysin, and ProGRP, were negative. Three months after the lobectomy, recurrent tumors were noted in the mediastinum and right thoracic wall, and she died despite combined chemotherapy and radiation therapy. In this case cytogenetic analysis showed a hypertriploid karyotype with multiple numerical and structural chromosomal aberrations, but failed to disclose distinct evidence of translocation between chromosome 11 and 22. However, the reverse transcriptase-polymerase chain reaction (RT-PCR) demonstrated EWS/FLI-1 fusion transcripts, confirming the histopathologic diagnosis of PNET. This case indicates that the primary pulmonary PNET is a highly aggressive neoplasm occurring at a young age, and should prompt combined systemic chemotherapy, even though it is organ-confined.

Malignant peripheral nerve sheath tumor arising in benign ancient schwannoma: a case report with an immunohistochemical study.

A rare example of malignant transformation in an ancient schwannoma arising in the right side of the neck of a 51-year-old man without any clinical manifestations suggesting neurofibromatosis is described. The tumor, approximately 4 cm at its largest dimension, was well circumscribed and had a direct connection with the sympathetic nerve. Microscopically, the central portion of the tumor showed features of ancient schwannoma characterized by extensive hyalinization with cystic degeneration, scattered spindle cells with hyperchromatic and tapered nuclei, and some symplastic changes. However, predominantly in the outer portion, a proliferation of spindle-shaped cells with enlarged nuclei was present. The nuclei of these cells showed irregular contours, coarse granular chromatin texture, and conspicuous nucleoli. Mitotic figures and small necrotic foci with scattered apoptotic bodies were also seen. Immunohistochemically, S-100 protein was almost negative in areas consisting of overtly atypical cells where the mitotic index evaluated with MIB-1 antibody was 30.5%. In contrast, S-100-positive bland spindle cells were scattered in an extensively hyalinized area with a labeling index less than 3%. P53 protein was strongly positive in atypical spindle cells. Although it is a very uncommon event, definite nuclear atypia, frequent mitotic figures, and the existence of small necrotic foci should be recognized as indicating a diagnosis of malignant degeneration of benign schwannoma. Immunohistochemistry would be useful as an ancillary technique in such a setting.