Nodular basement membrane deposits in breast carcinoma and atypical ductal hyperplasia: mimics of collagenous spherulosis.

Collagenous spherulosis is characterised histologically by the accumulation of hyaline globules containing basement membrane components. Originally described in the breast, it has also been found in skin and salivary gland neoplasms. In the breast it has hitherto always been associated with benign disease and reports have asserted that this is invariably the case, cautioning against the diagnosis of malignancy when the condition is seen. We present here five cases with similar appearances to collagenous spherulosis in routine histology and immunohistochemistry, and ultrastructural studies in one of them, in which the condition was not associated with simple benign breast disease. Two of the cases were associated with invasive carcinomas of unusual histological types, one with intracystic papillary carcinoma, one with comedo ductal carcinoma-in-situ and one with atypical ductal hyperplasia. We suggest that appearances similar to collagenous spherulosis can be associated, either through being formed by a lesion or by collision, with malignancy and warn that on encountering the lesions the pathologist must not assume, as suggested in previous accounts, that it denotes a benign process. This is an important observation since collagenous spherulosis is likely to be encountered more frequently in the range of lesions biopsied in national breast screening programs.

Relative usefulness of electron microscopy and immunocytochemistry in tumour diagnosis: 10 years of retrospective analysis.

AIMS: To determine retrospectively the relative usefulness of electron microscopy and immunocytochemistry for tumour diagnosis; to monitor the influence of new antibodies and antisera on the use of these techniques in one laboratory. METHODS: During 1980 to 1989 inclusive, 726 tumours were examined by electron microscopy, 862 by immunocytochemistry, and 286 by both techniques. The choice of techniques and, for immunocytochemistry, the range of antibodies used were compared between each category of final diagnosis. RESULTS: During the study period there was a sharp fall in the use of electron microscopy and a corresponding rise in immunocytochemistry. These trends applied to all categories of final tumour diagnosis, but the use of electron microscopy was sustained longer for lesions suspected or eventually confirmed to be melanomas or amine precursor uptake decarboxylation cell carcinoma (APUDomas)--for example, carcinoid tumours. The immunocytochemistry:electron microscopy use ratios ranged from 2.07:1 to 0.44:1 for the categories in which lymphoma and APUDoma, respectively, were the final diagnoses. The abandonment of electron microscopy for suspected or confirmed lymphomas and carcinomas corresponded to the increasing availability of relevant antisera and antibodies. CONCLUSIONS: The wider application of immunocytochemistry for tumour diagnosis is endorsed, but electron microscopy should be retained for selected cases in which the results of immunocytochemistry might be predictably ambiguous or otherwise unhelpful.

Immunohistochemistry and lectin histochemistry in sarcomatoid renal cell carcinoma: a comparison with classical renal cell carcinoma.

We investigated the expression of various cell markers in renal cell carcinoma, concentrating particularly on the sarcomatoid variety, using lectin and immunohistochemical techniques. The sarcomatoid variant showed stronger staining in a higher proportion of cases for vimentin and reduced positivity for epithelial membrane antigen, in comparison with classical renal cell carcinoma. All sarcomatoid tumours reacted with at least one cytokeratin, enabling them to be distinguished from true renal sarcomas; this is of diagnostic value when a panel of markers is used. Overall a similar pattern of markers is seen in sarcomatoid and classical renal cell carcinoma using lectin and immunohistochemistry, suggesting that the sarcomatoid variant arises as a metaplastic change rather than having a different histogenesis.