Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc
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Gastrointestinal stromal tumors (GISTs) form a distinctive group of mesenchymal neoplasms, showing differentiation towards the interstitial cells of Cajal. Morphologically, GISTs vary from cellular spindle cell tumors to epithelioid or mixed, epithelioid and spindle cell variants. The genotypic features underlying the morphologic differences of GISTs with vs without epithelioid components are not well defined. ⋯ All GISTs harboring PDGFRA mutant isoforms originated from the stomach. In seven tumors, no detectable mutations were found; all but one of nonmutant tumors initiated from the stomach and exhibited an epithelioid morphology. These findings indicate that the mutational status of epithelioid/mixed GISTs associates with the anatomical site of the tumor.
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Nonspecific interstitial pneumonia, a recently described form of idiopathic interstitial pneumonia, is characterized by uniform involvement of the alveolar septae with interstitial inflammation and variable amounts of fibrosis. Histological observations differentiate nonspecific interstitial pneumonia from usual interstitial pneumonia and clinically, patients with a nonspecific interstitial pneumonia pattern show better prognosis than those with usual interstitial pneumonia. We have genetically analyzed a family with a history of usual interstitial pneumonia. ⋯ DNA sequence analyses of the surfactant protein C gene in children with nonspecific interstitial pneumonia and adults with usual interstitial pneumonia exhibit a common heterozygous mutation located in exon 5. The mutation causes a Leu188 to Gln188 change in the carboxy-terminal region of prosurfactant protein C, possibly affecting peptide processing. These observations suggest that individuals with this particular mutation in surfactant protein C gene might be at increased risk of interstitial lung disease of variety of types.