Incidentally discovered distant cutaneous metastasis of sacral chordoma: a case with variation in S100 protein expression (compared to the primary tumor) and review of the literature.

Chordomas represent rare malignant primary bone tumors most often occurring in the sacral area. These tumors uncommonly involve the skin and often follow a progressive course with multiple recurrences, metastases and eventual death. Reports of cutaneous metastases from chordoma are very rare. The immunohistochemical staining characteristics of these cutaneous metastases with comparison to the primary tumors are similarly rarely addressed in the literature. We report a rare case of incidentally discovered, small, solitary distant cutaneous metastasis of sacral chordoma that developed on the right upper back of a 44-year-old man with a history of multiple completely excised melanomas who had also been previously diagnosed with chordoma involving the sacrum 12 years earlier. We describe its pathologic features with comparison to the primary tumor and briefly review the literature. Immunohistochemically, the cutaneous metastasis and primary tumor both stained positively for pancytokeratin and vimentin, as expected. However, the cutaneous metastasis unexpectedly lacked S100 protein expression, whereas the primary tumor was S100 positive. This phenomenon has only been documented in one other case report. We demonstrate that late, incidentally discovered cutaneous metastasis with unexpected immunohistochemical staining features rarely occur and can present a diagnostic challenge.

The diagnostic value of cell block as an adjunct to liquid-based cytology of bronchial washing specimens in the diagnosis and subclassification of pulmonary neoplasms.

BACKGROUND: To the authors' knowledge, the diagnostic value of cell block (CB) as an adjunct to ThinPrep liquid-based cytology (LBC) of bronchial washing specimens in the detection and subclassification of pulmonary neoplasms has not been well evaluated. The objective of the current study was to evaluate the diagnostic utility of CB in this setting. METHODS: A total of 74 bronchial washing specimens and concurrently prepared CBs with a diagnosis of malignant or suspicious/atypical obtained from bronchoscopy procedures performed during 2009 were reviewed along with 28 randomly selected negative cases. LBC and CBs were reviewed independently. Deeper levels and ancillary studies were performed on CBs for specific tumor classification if needed. LBC and CB diagnoses were correlated with final histology and/or bronchial brushings. RESULTS: Use of CBs increased the number of positive diagnoses from 18 (LBC only) to 30 (combined LBC and CB) and 36 (combined LBC and CB with ancillary studies), with increased diagnostic yields of 67% and 100%, respectively. CB without ancillary techniques detected 22 malignancies whereas LBC detected 18 malignancies and CB with ancillary techniques detected 29 malignancies. A specific tumor diagnosis was possible in 22 of 29 (76%) malignancies detected by CB. Bronchial brushings and histology confirmed malignancy in 91% and 92% of cases, respectively. CONCLUSIONS: CB combined with LBC was found to improve the rate of detection of malignancy over LBC alone, especially in cases with suspicious or atypical LBC diagnoses. Increased diagnostic yield is observed when CB is used with or without ancillary studies, but the yield is higher with CB using ancillary studies. CB serves as yet another available source of diagnostic material for immunohistochemical and molecular studies.

Prolonged stability of antimicrobial activity in peritoneal dialysis solutions.

OBJECTIVE: To evaluate the stability of the antimicrobial chemical and bioactivity of gentamicin, vancomycin, and gentamicin and vancomycin in combination, and the stability of the bioactivity of ceftazidime, admixed in standard peritoneal dialysis solutions and then maintained over a 14-day period at room temperature or under refrigeration. SETTING: Peritoneal dialysis center and microbiology laboratory at a military, teaching medical center. MEASUREMENTS: Standard peritoneal dialysate bags admixed with gentamicin, vancomycin, gentamicin and vancomycin in combination, or ceftazidime were stored at either 4 degrees C or 20 degrees C for 14 days. Sequential aliquots were withdrawn and assayed for antibiotic activity by bioassay and, except for ceftazidime, immunoassay for chemical activity. The bioassay was performed using a standardized Kirby-Bauer disc method. Significance was determined by ANOVA and, where the effect size was significant at the p < 0.05 level, the application of the paired t-test or the Wilcoxon signed rank test to the difference in activity between the first and last samples. RESULTS: Antibiotic concentration by immunoassay did not significantly deteriorate over 14 days for vancomycin or gentamicin when either room temperature or refrigerated samples were studied. By bioassay, gentamicin and ceftazidime, but not vancomycin, lost moderate but significant activity over 14 days when refrigerated bags were assayed (except for an insignificant decrement in gentamicin in the combined vancomycin and gentamicin bags). Bags stored at room temperature, in general, lost significant bioactivity over 14 days, but to levels where clinical efficacy would still be expected. The vancomycin bioassay performed on the combination bags demonstrated a remarkably enhanced bioactivity, presumably reflecting synergy with gentamicin. CONCLUSION: These data indicate that the study antibiotics admixed with peritoneal dialysis fluids retain stable chemical activity, whether refrigerated or kept at room temperature, for at least 14 days. A moderate decrement in bioactivity occurred for study antibiotics when stored either refrigerated or at room temperature over 14 days, although clinically significant levels were maintained. The clinical significance of a possible synergy between vancomycin and gentamicin is yet to be determined.