Epithelial-myoepithelial carcinoma harboring p53 mutation.

A case of epithelial-myoepithelial carcinoma of the parotid gland harboring p53 mutation is reported. The tumor removed from a 67-year-old Japanese female was composed of an organoid biphasic population of cells: inner dark epithelial cells were surrounded by clear myoepithelial cells. The cells were immunopositive for EMA and smooth muscle actin, respectively. Some of the epithelial cells formed solid nests. Immunostaining for proliferating cell nuclear antigen (PCNA) resulted in a higher percentage of labeled cells in the solid epithelial region than in the region with the more general biphasic pattern. Genetic analysis, including polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) and nucleotide sequencing, revealed a mutation in codon 207 (aspartic acid to glycine) of the p53 tumor-suppressor gene. To our knowledge, this is the first report of a mutation in the p53 gene in an epithelial-myoepithelial carcinoma of the salivary gland.

A case of bladder pheochromocytoma.

The clinical picture of bladder pheochromocytoma is usually typical; however, the diagnosis is occasionally delayed because of the rarity of this neoplasm. We report a case of unsuspected bladder pheochromocytoma in which the patient had a hypertensive episode during transurethral resection. A 67-year-old male presented with the chief complaint of painless macrohematuria. Cystoscopy revealed a submucosal tumor on the right lateral wall of the bladder. The tumor was operated on transurethrally, followed by partial cystectomy. The pathological diagnosis was pheochromocytoma, primarily occurring in the bladder. Treatment of this lesion requires a high degree of clinical suspicion based on the patient's symptom complex in order to enable adequate preparation prior to surgical manipulation.

Myxoid adrenal cortical adenoma.

Myxoid adrenal cortical adenoma is a rare tumor and, to our knowledge, only 16 cases have been reported. We present the case of a 56-year-old Japanese man who was admitted to hospital because of a right adrenal mass that was discovered during a routine physical examination. The resected mass was well circumscribed and contained canary yellow multinodular regions that were surrounded by a brown gelatinous region. Histologically, the multinodular regions resembled a conventional adrenal cortical adenoma, being composed of solid aggregates of large clear or eosinophilic cells. In the gelatinous region, anastomosing small eosinophilic or vesicular cells were visible within a myxoid stroma that contained large amounts of acidic mucopolysaccharides. Light-microscopic findings were consistent with a diagnosis of adenoma. Immunohistochemical staining revealed that a small number of tumor cells were positive for vimentin, and the MIB-1 labeling index was less than 1%. Flow cytometry demonstrated that cells were diploid. At the ultrastructural level, many fat droplets were found in the large clear cells in the multinodular regions. Small eosinophilic cells in the myxoid region contained many mitochondria but few fat droplets. There were no findings suggestive of malignancy. Although the adrenal cortex might have the potential to produce connective tissue-type mucin as a consequence of its mesodermal origin, the mechanism of production of acidic mucopolysaccharides in a myxoid adrenal cortical tumor remains to be clarified.

Leiomyoma of the parapharyngeal space.

A rare case of leiomyoma of the prestyloid parapharyngeal space is reported together with computed tomographic and magnetic resonance imaging findings. The tumor appeared as a well-circumscribed ovoid mass with some calcifications and lobulations. Because the attenuation, signal intensity, and shape of the mass were not specific and were similar to those of a pleomorhic adenoma, the most common tumor of the prestyloid parapharyngeal space, radiological differentiation of leiomyoma from pleomorphic adenoma of the prestyloid parapharyngeal space was difficult.

Rhabdomyosarcoma of the urachus. A case report.

BACKGROUND: Rhabdomyosarcoma of the urachus is extremely rare, and only two cases have been reported. Cytologic, histologic, immunochemical and electron microscopic findings in embryonal rhabdomyosarcoma of the urachus are presented. CASE: Embryonal rhabdomyosarcoma of the urachus developed in a 2-year-old boy. Imprint smears prepared prior to a histologic examination for a rapid report contained many malignant cells isolated or in clusters in a myxoid background. They were uniformly small, with round to oval nuclei and scant cytoplasm, and immunohistochemically positive for desmin and alpha-sarcomeric muscle actin but negative for myoglobin. This tumor was diagnosed cytologically as embryonal rhabdomyosarcoma because of its skeletal muscle origin and because of its similarity to one of the so-called small round cell tumors of childhood. Histologic examination confirmed the cytologic diagnosis. CONCLUSION: Cytologic, histologic and electron microscopic findings were identical to those described previously for embryonal rhabdomyosarcoma at other sites. In immunochemical examinations, cytologic samples fixed in ethanol are more useful than histologic ones fixed in formalin. Then, in order to differentiate poorly differentiated rhabdomyosarcoma from other small round cell tumors in children, desmin and alpha-sarcomeric actin, rather than myoglobin, are recommended.

Cytologic features of solid and cystic tumor of the pancreas.

OBJECTIVE: To describe the cytologic features of solid and cystic tumor of the pancreas. STUDY DESIGN: Cytologic features of four cases of solid and cystic tumor of the pancreas (SCT) were reported and compared with those of three cases of islet cell tumor of the pancreas. RESULTS: Aspiration and imprint cytology of the tumor cells obtained from three cases of SCT showed papillary structures or rosette formations in part and demonstrated uniformly round to oval nuclei that contained finely granular chromatin, a fairly distinct nucleolus and a scant to moderate amount of granular or vesicular cytoplasm. Another case of SCT consisted of multinucleated giant cells with coherent chromatin as well as mononuclear cells with nuclear grooves. Islet cell tumor consisted mainly of clustered or isolated uniform mononuclear cells with rosette formations but without a papillary structure and occasional multinucleated giant cells in all cases. The nuclei of islet cell tumors had peculiar, fine chromatin aggregates with a "salt-and-pepper" appearance and slightly enlarged nucleoli. CONCLUSION: SCT is cytologically distinguishable from islet cell tumor in spite of having many cytologic features in common with it.