A clear cell variant of follicular carcinoma presenting as an autonomously functioning thyroid nodule.

We report a case of an autonomously functioning thyroid nodule (AFTN) that proved to be almost exclusively a clear cell variant of follicular carcinoma. AFTNs are generally felt to be benign lesions with exceptions forming the basis of case reports. Likewise, clear cell tumors of the thyroid are rare. To our knowledge, this combination of two unusual thyroid conditions has not been previously reported. The initial scans of this patient were so characteristic for a degenerating AFTN that attention was first directed toward a very large contralateral lobe. While it is debatable whether all AFTNs should be biopsied, on the basis of this and other cases, it is recommended that AFTNs that contain a central photopenic area on scan be biopsied to be sure that cystic degeneration, a commonly seen phenomenon in larger AFTNs, is indeed present rather than a malignancy.

Toxicity of N-methyl-2-pyrrolidone (NMP): teratogenic, subchronic, and two-year inhalation studies.

Pregnant rats were exposed to N-methyl-2-pyrrolidone (NMP) at atmospheric concentrations of 0.1 and 0.36 mg/liter for 6 hr/day on Days 6 through 15 of gestation. Except for sporadic lethargy and irregular respiration in several rats the first 3 days of exposure, there were neither abnormal clinical signs nor pathological lesions in the maternal rats. Exposure did not affect either the outcome of pregnancy or embryonal growth rate. No abnormal development was detected in the vital organs and skeletons of the fetuses. Rats were exposed to an aerosol-vapor mixture of NMP at concentrations of 0, 0.1, 0.5, and 1.0 mg/liter for 6 hr/day, 5 days/week for 4 weeks. At 0.1 and 0.5 mg/liter exposure levels, rats did not show any significant clinical signs or pathological lesions. However, lethargy, respiratory difficulty, and excessive mortality were found in rats exposed to 1.0 mg/liter. These rats had focal pneumonia, bone marrow hypoplasia, and atrophy of lymphoid tissue in the spleen and thymus. These lesions were reversible in surviving rats following 2 weeks of recovery. Increases in the relative and absolute numbers of neutrophils were observed during exposure at 1.0 mg/liter, but returned to normal limits after 2 weeks of recovery. Rats were exposed to vapor of NMP at concentrations of 0, 0.04, or 0.4 mg/liter for 6 hr/day, 5 days/week for 2 years. Male rats at 0.4 mg/liter showed slightly reduced mean body weight. No life-shortening toxic or carcinogenic effects were observed in rats exposed for 2 years to 0.04 or 0.4 mg/liter of NMP.

Inhalation toxicity study on rats exposed to titanium tetrachloride atmospheric hydrolysis products for two years.

Rats were exposed to TiCl4 hydrolysis products by inhalation exposure at aerosol concentrations of 0, 0.1, 1.0, and 10 mg/m3 for 6 hr/day, 5 days/week for 2 years. There were no abnormal clinical signs, body weight changes, or excess mortality in any exposed groups. No pathological changes other than a mild rhinitis were observed at 0.1 mg/m3. At 1.0 mg/m3, the incidence of mild rhinitis and tracheitis was increased. The lungs showed a minute dust-laden macrophage (dust cell) reaction with slight Type II pneumocyte hyperplasia in alveoli adjacent to the alveolar ducts. The pulmonary response at the 1.0 mg/m3 satisfied the biological criteria for a nuisance dust. At 10 mg/m3, extrapulmonary particle deposition occurred in the tracheobronchial lymph nodes, liver, and spleen without any tissue response. An increased incidence of rhinitis, tracheitis, and dust cell response with Type II pneumocyte hyperplasia, alveolar bronchiolarization, foamy dust cell accumulation, alveolar proteinosis, cholesterol granuloma, and focal pleurisy was also observed. The pulmonary lesions developed in the alveolar duct region where dust cells had accumulated and had provoked a chronic tissue response. In addition, a few well-differentiated, cystic keratinizing squamous carcinomas were developed from alveoli showing bronchiolarization with squamous metaplasia in the alveolar duct region. No tumor metastasis was found in other organs. The lung tumors were a unique type of experimentally induced tumor and have not been seen usually in man or animals. Therefore, the relevance to man of this type of lung tumor is highly questionable.

The use of quantitative cultures and antibody coating of bacteria to diagnose bacterial pneumonia by fiberoptic bronchoscopy.

This study uses quantitative cultures and immunofluorescent demonstration of antibody-coated bacteria to differentiate colonizing from infecting bacteria in lower respiratory secretions obtained by fiberoptic bronchoscopy. The fiberoptic bronchoscope was passed transnasally without the use of a nasotracheal tube, and a single-sheath cytology brush dipped in lower respiratory secretions served as inoculum for quantitative cultures. Secretions were also collected by aspiration through the bronchoscope side channel for fluorescent examination. None of 60 control patients had greater than 4,000 colony-forming units (CFU) per brush of a single bacterium on quantitative culture. In contrast, more than 4,000 CFU per brush were isolated from 29 of 33 episodes of clinically defined lower respiratory infection (p less than 0.001). Only 1 of 60 control patients had antibody-coated bacteria in their lower respiratory secretions, but antibody coating was demonstrated in association with 24 of 33 episodes of infection (p less than 0.001).

Morphologic expression of glandular differentiation in the epidermoid nasal carcinomas induced by phenylglycidyl ether inhalation.

Charles River-CD Sprague-Dawley rats in 3 equal groups of 100 males and 100 females each were exposed to 12, 1, and 0 ppm of phenylglycidyl ether vapor for 24 months. Nasal tumors were first detected after 621 days' exposure at 12 ppm with an incidence of 11% in males and 4.4% in females. No nasal tumors were found at 1 ppm in rats exposed for 24 months. The nasal tumors, mostly epidermoid carcinomas, were derived from the respiratory epithelium and nasal glands, both of which revealed squamous metaplasia or dysplasia in the anterior nasal cavity. Most nasal tumors were confined to the anterior nasal cavity and occasionally invaded the dorsonasal bones and posterior nasal cavity. The undifferentiated glandular cells appear to differentiate to neoplastic squamous cells, because the ultrastructure of epidermoid carcinoma revealed traits of glandular cell differentiation in the neoplastic squamous cells. The features of glandular cell differentiation in the neoplastic squamous cells were intercellular or intracellular glandular lumens, secretory vesicles, mucus droplets, and intermediate cells showing both glandular and squamous differentiation. Squamous cells in the well-differentiated epidermoid carcinomas revealed abundant tonofibrils, desmosomes, glycogen particulates, and interdigitated cytoplasmic processes. These markers of squamous-cell differentiation were markedly reduced in the undifferentiated epidermoid carcinomas. The spindle-cell squamous carcinoma showed both squamous and fibroblastic-like differentiations. Some spindle cells had only fibroblastic-like differentiation, suggesting spindle-cell metaplasia of the squamous cells.