Histologic demonstration of glycosaminoglycan (GAG) deposition in the skin has been based on the use of either colloidal iron or alcian blue. To define the best technique for the determination of skin GAG content we undertook a prospective study comparing the two stains and evaluating the use of cetylpyridinium chloride (CPC) to enhance fixation. Slides were prepared from skin biopsies obtained from five patients with cutaneous mucinoses. The preparations were coded and examined by three observers. Colloidal iron staining gave a higher intensity for GAG deposits in papillary and reticular dermis. Digestion by specific enzymes identified similar GAGs with either colloidal iron, or alcian blue; however, colloidal iron made GAGs more obvious, partly due to the contrast afforded by the yellow background stain. The addition of CPC to the fixative appreciably enhanced GAG fixation without interfering with the action of enzymes. Experimentally, we confirmed this effect of CPC by determining a pronounced decrease in GAG leakage into the fixative from CPC treated human umbilical cord. We conclude that the combination of CPC fixation and colloidal iron staining gives the best definition of skin GAGs in clinical specimens.
Malignant thymoma is a mediastinal tumor which spreads primarily by local invasion. Spread to regional lymph nodes and distant organs is variable. The most common sites of metastasis in the head and neck region are the supraclavicular nodes and the brain. Cervical lymph node metastasis as the presenting symptom of malignant thymoma has not yet been reported in the otolaryngologic literature. We present three cases of metastatic thymoma to the neck from a series of 28 thymomas, ten of which were malignant. The clinical presentation, histopathological features, therapy, and prognosis of malignant thymomas are discussed.
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