Study of serum amyloid A concentrations as a means of achieving early diagnosis of Rhodococcus equi pneumonia.

REASONS FOR PERFORMING STUDY: Prognosis of Rhodococcus equi pneumonia can be challenging because the course of the disease is often insidious and overt clinical signs are subtle. Early diagnosis is considered desirable because it may offer the chance of more successful implementation of treatment and, thereby, improved outcome. Serological tests have previously failed to be accurate for early detection or diagnosis. Measurement of serum amyloid A (SAA) prior to and at the time of clinical signs was therefore chosen in order to assess its potential clinical use. OBJECTIVE: To determine whether SAA concentrations differentiate foals affected with R. equi pneumonia from unaffected foals, either prior to the onset of disease or at the time of onset of clinical signs. HYPOTHESIS: SAA concentrations are significantly higher among foals that develop R. equi pneumonia than in foals from the same environment that remain clinically unaffected. METHODS: Serum samples were obtained from 212 foals 7-14 days and 196 foals 21-28 days post partum, and from affected foals and age-matched controls at the time of onset of signs of pneumonia. SAA concentration was determined for each sample. RESULTS: There were no significant differences between SAA concentrations of foals with R. equi and clinically unaffected foals during the 2 periods of examination or at the time of onset of clinical signs of R. equi pneumonia. CONCLUSIONS: Concentrations of SAA are variable among foals with R. equi pneumonia and cannot be used reliably either as an ancillary diagnostic tool or to screen for early detection of disease during the first month post partum. POTENTIAL RELEVANCE: Bimonthly monitoring concentration of SAA is not useful as a screening test for early detection of R. equi pneumonia and does not facilitate diagnosis of this disease when used according to the protocol of this study.

Basaloid squamous carcinoma of the head and neck. Report of a case occurring in the anterior floor of the mouth.

Basaloid squamous carcinoma was initially characterized in 1986, and it has been an uncommon entity, with 86 reported cases occurring in the head and neck. Although histologically associated with squamous cell carcinoma and squamous atypia, basaloid squamous carcinoma has distinctive clinical features. It is frequently diagnosed at an advanced stage, often with distant metastases, and it may be associated with second primary tumors. This tumor most commonly occurs in the base of the tongue, hypopharynx, and larynx. We report a case of basaloid squamous carcinoma that occurred in the anterior floor of the mouth--a distinctly unusual location.

Carcinosarcoma (malignant mixed tumor) of the parotid: report of a case with a pure rhabdomyosarcoma component.

BACKGROUND: Carcinosarcoma or true malignant mixed tumor of the parotid gland is extremely rare, accounting for < 1% of all salivary gland malignancies. METHODS: A 63-year-old woman presented with a 5-cm right parotid mass which was resected with a radical parotidectomy and infratemporal fossa dissection. RESULTS: The tumor contained two distinctive histologic patterns, that of a poorly differentiated ductal carcinoma and a pleomorphic rhabdomyosarcoma. Additionally, a residual focus of pleomorphic adenoma was present peripherally. Immunohistochemical and electron microscopic studies confirmed the skeletal muscle differentiation. CONCLUSIONS: The pattern of combined rhabdomyosarcoma and ductal carcinoma has not been previously reported and adds further evidence to the myoepithelial derivation of these tumors.

DNA content of head and neck squamous carcinoma by flow and image cytometry.

OBJECTIVE: To compare the measurement of quantitative DNA in squamous cell carcinoma of the head and neck by flow cytometry and image cytometry. DESIGN: Comparison of image cytometry to the more commonly used flow cytometry using paraffin-embedded tissues. SETTING: University of California, Davis Medical Center, Sacramento. A 472-bed university teaching hospital. PATIENTS: Records of 26 patients with squamous cell carcinoma of the tongue, base of tongue, and larynx were obtained from the case files of an otolaryngologist-head and neck surgeon. They were reviewed for staging and follow-up. RESULTS: We demonstrated a 96% concordance rate between the methods. A solitary discrepant case was aneuploid by image cytometry and diploid by flow cytometry. The specimen involved tumor infiltrated by lymphocytes that may have masked the aneuploid population to measurement by flow cytometry. Quantitative DNA analysis correlated moderately well with tumor grade, tumor stage, and patient outcome with a minimum of 6 years of follow-up. All patients with diploid tumors were long-term survivors. CONCLUSIONS: Both methods provide accurate quantitative DNA analyses in squamous cell carcinoma of the head and neck. The methods are highly correlative and yield similar predictive data regarding tumor behavior and prognosis.

Clinical utility of intraoperative frozen section diagnosis in head and neck surgery: a quality assurance perspective.

The technical and professional issues that affect the clinical utility of intraoperative frozen section diagnosis in head and neck surgery are addressed from a quality assurance perspective. The most common reasons for sampling errors and interpretive errors are discussed. We offer several recommendations for head and neck surgeons and pathologists which will optimize the clinical utility of intraoperative frozen section consultation.

Intraoperative frozen section diagnosis in skull base surgery.

During January 1990 through June 1992, we performed 39 surgeries for base of skull tumors with extracranial and intracranial involvement on 33 patients. Intraoperative frozen section was requested on 581 of 904 specimens submitted (64%). There was a discrepancy between the frozen section diagnosis and final diagnosis in 15 specimens for an error rate of 3%. There were two false-positive diagnoses of malignancy and 13 false-negative diagnoses. The discrepancies were a result of sampling error in ten cases and of interpretive error in five cases. Four of the five interpretive errors involved intradural tissues. Only two of the discrepancies were clinically significant. One involved the evaluation of adequacy of surgical margins and a second involved the misinterpretation of metastatic renal cell carcinoma for hemangioblastoma. We recommend careful attention to cryostat sectioning and interpretive experience in head and neck pathology and neuropathology. The importance of vigilant communications between surgeon and pathologist before, during, and after surgery cannot be overstated. We are utilizing a video-linked microscopic network that allows the surgeon to view the frozen section histologic sections in the operating room. Future trends may include the use of monoclonal antibodies and morphometry to improve accuracy in frozen section diagnosis.

Accuracy of intraoperative frozen section diagnosis in head and neck surgery: experience at a university medical center.

We performed 2,210 intraoperative frozen sections on 258 patients from the Otolaryngology-Head and Neck Surgery Service in 1990 and 1991. Surgery involved a wide variety of benign and malignant lesions. Techniques included biopsies for diagnosis, simple excision, thyroid and salivary gland surgeries, lymph node biopsies, composite resections with radical neck dissections, laryngectomies, and skull base surgeries. During the 2-year period, 1,947 (88.1%) sections were requested for evaluation of surgical margins, 258 (11.7%) for diagnosis, and five (0.2%) cases for tissue identification. There was disagreement between the frozen section and permanent section in 46 (2.1%) cases, and the deferral diagnosis rate was 0.8%. Disagreements were the result of sampling errors in 33 and interpretive errors in 13 cases. There were six (0.3%) false-negative diagnosis of malignancy and four (0.2%) false-positive diagnoses of malignancy. Three of these had an impact on patient care as discussed. We recommend careful sampling and sectioning of small biopsies and the need for vigilant communication between surgeon and pathologist.