Intraneural perineurioma involving the median nerve.

Intraneural perineurioma is a rare clinical entity, which tends to affect major nerve trunks in the upper extremities. On light microscopy, numerous pseudo-onion-bulb structures having a central clear area are surrounded by concentric layers of eosinophilic elongate cells having spindled nuclei. Immunohistochemistry of concentric cells stains positive for epithelial membrane antigen but negative for S100 protein. Because of the small number of cases, no consensus has been made on proper treatment of this entity. Although none of the patients who have had excision of tumor with nerve grafting have had sensory nerve recovery, we believe each patient should be individualized until more data are available regarding this tumor.

Revision hip arthroplasty with the use of cement and impaction grafting. Histological analysis of four cases.

The findings of radiographic studies have suggested that the cementing of an implant with a polished tapered stem into a bed of impacted bone allograft may provide adequate function of the joint and may restore bone in the proximal part of the femur. However, radiographs of hips with cancellous bone graft adjacent to cement are difficult to interpret, and the viability of impacted bone graft that is adjacent to cement and its capability for remodeling are unclear. To evaluate this interface further, we obtained biopsy specimens from the proximal part of the femur at the time of removal of trochanteric wires from four patients eleven to twenty-seven months after revision hip arthroplasty with cement and impaction grafting. Three relatively ill defined zones were identified histologically: an inner zone consisting of bone cement, fibrous tissue, and partially necrotic trabeculae with evidence of bone-remodeling; a middle zone consisting of viable trabecular bone and probable formation of so-called neocortex with fewer particles of bone cement; and an outer zone consisting of viable cortex. Fibrous tissue was present around some of the incorporating fragments of bone graft, but no continuous fibrous membrane was seen. Particles of cement were identified, but no polyethylene debris was visible on examination with light microscopy. The results demonstrated remodeling of bone and at least partial restoration of bone stock in the proximal part of the femur after revision arthroplasty with cement and impaction grafting.

Hematoidin crystals in cervicovaginal smears. Review of 27 cases seen in one year.

The occurrence of hematoidin crystals in cervicovaginal smears has recently been described. A prospective search for hematoidin crystals in smears taken during a one-year period was carried out, with a subsequent retrospective chart review. This study revealed that the occurrence of hematoidin crystals was more common than previously thought and was often associated with pregnancy or pregnancylike states. The clinical correlations and possible etiologies of this finding are discussed.

Thymomas.

Forty-six thymomas, defined as neoplasms of thymic epithelium, were assessed in respect to histologic type, clinical manifestations and end results. Twenty-three were lymphoepithelial, 12 epithelial, and 11 spindled cell tumors. The sex distribution for all thymomas was approximately equal for males and females but the lymphoepithelial tumors were more common in females and the epithelial tumors more common in males. There was no distribution difference in sex for the spindled cell thymomas which occurred much later in life than the other types. Twenty-five percent of patients were asymptomatic, the tumors being discovered on roentgenograms done on a routine basis or for an unrelated purpose. The most common presenting symptoms were related to myasthenia gravis, and symptoms due to pressure on mediastinal structures were next in frequency. Other endocrine abnormalities were present in 20% of patients. Two male patients also had carcinomas of the thyroid gland. Twenty thymomas were infiltrative tumors having invaded the adjacent mediastinum. There were no examples of extrathoracic spread. Twelve of 16 patients with myasthenia gravis had lymphoepithelial thymomas and four epithelial thymomas. There were no cases of myasthenia gravis in patients with spindled cell thymomas. The crude five-year survival rate was 65%. Only 17% of patients died as a result of recurrent and infiltrative thymomas; the other 18% of patients died from a variety of causes not directly related to the thymomas. The epithelial type of thymoma tended to be more extensive and to pursue a more aggressive course but histologic classification was of little value in predicting final outcome. Poor prognosis is more closely associated with tumors having an infiltrative character. Classification is of importance, however, in alerting the clinician to certain associated diseases.

Parathyroid hamartoma: report of two cases and review of the literature.

Parathyroid hamartomas are rare. Only four cases, two of which are associated with clinical hyperparathyroidism, have been reported in the literature. This is a report of two additional cases of functioning parathyroid hamartomas, one accompanied by proliferating fat and the other by a myxomatous, fibrillar stroma.

Intraduodenal sarcoma. A case report.

A case of a duodenal and a pancreatic pleomorphic sarcoma which was diagnosed as a malignant undifferentiated neoplasm cytologically is described. Primary malignant sarcomas at this site are highly unusual. The importance of endoscopic brush cytology is emphasized.