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Two cases of rectal carcinoid tumors are reported. In the first case the endoscopic diagnosis was intramural rectal neoformation. At histology, rectal carcinoid tumor with infiltration of the muscularis mucosae was diagnosed. Abdominoperineal resection was performed. The patient is still living 3 years following surgery. In the second case, the endoscopic diagnosis was non-adenomatous polyp. Endoscopic polypectomy was performed. At histology, rectal carcinoid tumor was diagnosed. The patient is still living 2 years following surgery.

The clinical and pathologic findings of four cases of palpable sclerosing adenosis of the breast, called "adenosis tumor", are reported. Adenosis tumor is a rare lesion that clinically and sometimes histologically is misinterpreted as mammary carcinoma. In our study, adenosis tumor was detected in four women of 35-39 years (average 37 years). All cases were treated by local excision. None of the lesions had recurred at follow-up, 1-3 years later. Microscopically the most frequent growth pattern was classical sclerosing adenosis. Other findings were epitheliosis, collagenous spherulosis, microcysts, apocrine metaplasia and radial scars. Only in one case were detected foci of lobular carcinoma in situ. With immunoperoxidase staining, the proliferating cells stained positively for cytokeratin (AE1/AE3) and actin, revealing epithelial and myoepithelial differentiation. Coexpression of actin, S-100 protein and GFAP was detected in numerous stromal myofibroblast-like cells. In sclerosing adenosis and in radial scar the tubules were surrounded by a continuous intact basement membrane composed of type IV collagen, whereas in tubular carcinoma basement membranes are almost entirely absent.

We have chosen 10 medullary carcinomas from a retrospective investigation on 450 cases of breast carcinoma (2.2%), according to the histomorphological criteria of Ridolfi and colleagues. By immunoperoxidase staining, we have evaluated the distribution of keratin and vimentin intermediate filaments, of CEA and S-100 protein in cancer cells. A widespread positivity to keratins has been proved in 70% of medullary carcinomas. Numerous neoplastic cells have coexpressed S-100 protein. We hypothesize the epithelial and myoepithelial "intermediate" differentiation of keratin and S-100 protein positive tumour cells.