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Glutathione S-transferase (GST) mu phenotype was assessed in colon tissue from patients with ulcerative colitis and colorectal neoplasms that were positive for GSTM1 genotype. GST mu protein (enzyme linked immunosorbent assay) was absent in 2/9 unaffected colon tissue (22.3%), 4/13 tissues with chronic ulcerative colitis (CUC) (30.7%), 4/11 adenomas (36.4%) and 7/14 adenocarcinomas (50.0%; P

A 74-year-old man was found to have a 1 cm, slightly elevated and flat, red mucosal lesion of the descending colon. An endoscopic biopsy showed a structure characteristic of a tubular adenoma. The surgical specimen revealed an inverted, transmural, solid and cystic lesion. The superficial (intra-mucosal) component of the neoplasm was histologically characteristic of a flat adenoma, showing epithelial dysplasia. However, the contiguous deep component was a well-differentiated adenocarcinoma extending to the serosa and demonstrating the unusual features of a circumscribed lobulated topography and the absence of an inflammatory/desmoplastic stromal reaction. Endophytic malignant transformation within a flat adenoma should be distinguished from conditions of misplaced glandular epithelium such as localized colitis cystica profunda. Complete and full mucosal thickness endoscopic snare removal is indicated in order to assess the degree of epithelial dysplasia and detect endophytic malignant transformation.

A case of heterotopic bone formation in a primary rectal adenocarcinoma was recently observed in a 54-year-old woman. This unusual finding was present both in the diagnostic biopsy and in the subsequently resected bowel. Pertinent gross and microscopic features are presented. This report represents the twelfth case in the literature of heterotopic bone formation in a primary rectal adenocarcinoma and the first such finding in a colonic biopsy from one of these malignancies. The average age of these patients was 56 years (range 32-72) and the male-to-female ratio was 5:7. The rectum is the most common site of ossification in the gastrointestinal tract. The exact mechanism of heterotopic ossification is unknown, but it is probably the result of metaplasia of fibroblasts. Adenocarcinoma has been associated with 12 of the 16 reported cases of rectal glandular tumors with heterotopic bone.

We report two cases of peripheral biphasic adenocarcinoma primary in the lung. To our knowledge, peripheral adenocarcinoma of the lung with a spindle-cell component has not been described previously. Diffuse positive cytokeratin and negative vimentin immunostaining of the spindle-cell components support an epithelial differentiation of the malignant spindle cells. Although study of additional cases is needed, our initial findings suggest that immunohistochemical staining pattern may help distinguish these neoplasms from other biphasic neoplasms primary or secondary to the lung, such as carcinosarcoma or malignant mesothelioma.