Fano Ra

Synchronous occurrence of epithelial and stromal tumors in the stomach: a report of 6 cases.

OBJECTIVE The synchronous development of epithelial and stromal tumors in the stomach has been reported rarely in the literature. A series of 6 such cases is described in this article. METHODS Clinical and pathologic data were recorded and the literature was reviewed. RESULTS Five cases featured the simultaneous occurrence of stromal tumors (1 benign, 3 borderline, 1 malignant) and adenocarcinomas, whereas the stromal tumor in the sixth case was found in association with a carcinoid. No collision tumors were observed. In 2 cases, tumors arose from the same site and were closely juxtaposed, but in 4 patients they developed from different areas of the stomach. A preoperative histologic diagnosis of both tumors was not achieved in any case. Two patients harbored occult infiltrative epithelial lesions (1 diffuse-type adenocarcinoma, 1 carcinoid), which were detected only at pathologic examination of the gastric mucosa adjacent to the stromal tumor. CONCLUSIONS The simultaneous occurrence of epithelial and stromal tumors in the stomach can be less rare than usually expected. Coincidence alone could account for such an association, particularly in areas with high incidence rates of gastric cancer. The hypothesis that a single carcinogenic agent might interact with two neighboring tissues in the stomach inducing the development of tumors of different histotype cannot be theoretically discarded.

Expression of MHC class I and class II antigens in primary breast carcinomas and synchronous nodal metastases

Expression of the major histocompatibility (MHC) class I and class II antigens was studied by immunohistochemistry in a series of 70 primary breast carcinomas and in nodal metastases. In particular, the expression of class I (HLA A-B-C) and class II (DP, DQ and DR) molecules was compared in: a) primary breast cancers devoid of nodal metastases (n = 36) and tumors exhibiting metastatic deposits (n = 34) at the time of surgery, and b) primary breast carcinomas and their corresponding synchronous axillary nodal metastases. Reduced or absent HLA A-B-C antigen expression was seen in approximately 54.3% of primary breast carcinomas, whereas a partial or complete induction of class II products was observed in 18.5% (DQ), 30% (DP) or 48.5% (DR) of the same cases. An almost complete overlap of antigen expression was observed in breast tumors in which no metastases were found by histological examination of axillary nodes and in neoplasms showing histologically-diagnosed synchronous metastases. The reactivity for class I and class II antigens in nodal metastases roughly paralleled that exhibited by corresponding primary tumors. A discordant expression was seen in 11 cases (32%) stained for HLA A-B-C and in 8 (24%), 7 (21%) and 6 (18%) cases assayed for DP, DQ and DR products, respectively. When a discordant expression was detected, either decreased or increased staining patterns were observed in metastases. The finding of overlapping MHC antigenic profiles in the majority of primary breast tumors and nodal metastases casts doubts on the hypothesis that loss of MHC antigens can play an important role in the seeding and growth of metastatic breast carcinoma cells.

Combined neuroendocrine carcinoma of the skin (Merkel cell tumor) and trichilemmal cyst.

We report a case of neuroendocrine (Merkel cell) carcinoma (NC) of the skin, associated with a trichilemmal cyst, showing pagetoid spread into the trichilemmal epithelium. The association of the two lesions may strengthen the hypothesis that NC originates from pluripotent stem cells of adnexal epithelium.

Epithelioid angiosarcoma of the thyroid

Epithelioid angiosarcomas of the thyroid usually develop in people living in Alpine regions, and only rare cases arising in subjects living in nonmountainous areas have been reported. We describe the clinicopathological features of a series of seven cases collected from non-Alpine areas. All patients were adults. The tumours appeared as haemorrhagic, unencapsulated, sometimes cystic nodules. In two cases multinodularity was present. They were composed of large, epithelioid cells, which lined vascular-like spaces or were arranged in solid sheets. Intracytoplasmic lumina containing red blood cells were identified. Neoplastic cells were diffusely positive for factor VIII-related antigen, Ulex europaeus agglutinin, CD31 and keratin peptides. Ultrastructural studies were performed in four cases and showed features of endothelial differentiation. An average follow-up of 3.8 years disclosed that four patients died of disease after a median survival time of 5 months, whereas 3 patients are still alive with no evidence or residual disease 27, 32 and 66 months after thyroidectomy. The good prognosis in these patients appears to be related mainly to the absence of extraglandular tumour spread at the time of surgery.

Metastatic capacity and differentiation in murine melanoma cell lines: A Morphometric Study

A morphometric analysis was carried out on electron micrographs of cells of the F1 (low metastatic capacity) and F10 (high metastatic capacity) variant sublines of the murine B16 melanoma, both in in-vitro cultures and in lung-metastatic nodules developed after the intravenous injection of neoplastic cells in syngeneic C57 black male mice. A group of 28 morphometric parameters was derived to describe quantitatively each neoplastic cell profile. No qualitative difference was observed between the two cell lines. The quantitative expression of subcellular organelles was dissimilar in the two sublines, being consistently characterized, both in in-vitro cultured cells and in lung-metastatic colonies, by a significant decrease in the mean values of parameters related to melanosomes in the high metastatic capacity cell line (B16-F10). Moreover, in in-vitro cultured cells, indices describing heterochromatin masses and cytoplasmic membranous compartments displayed statistically significant differences between the two sublines. In this experimental system, an inverse relationship between metastatic capacity and differentiation is detected, since cells with a more aggressive metastatic behavior exhibit a decreased degree of differentiation.