A morphological and immunocytochemical study of a distinctive variant of ductal carcinoma in‐situ of the breast

Abstract

Because so-called carcinoid tumor of the breast is a difficult entity to define, in-situ carcinoma was studied in order to help clarify the complex problems involved. A consecutive series of 30 cases of ductal carcinoma in-situ (DCIS) was studied by light microscopy and silver impregnation methods, and a relatively common endocrine variant of DCIS was identified. This variant was studied by immunocytochemical and ultrastructural methods, using conventional DCIS as a control. Endocrine DCIS is identified by its organoid pattern, stromal inclusions, festooned structure and a distinctive type of polypoid invagination. It is argyrophilic and rich in neuron-specific enolase. Ultrastructurally it contains abundant dense core granules which are impregnated selectively by Grimelius'' method. This tumor type frequently contains peptide hormones of the ACTH family. Three of 7 cases contained cells reactive for ACTH and corticotropin-like intermediate lobe peptide (CLIP) or their percursor, proopiomelanocortin. A 4th tumor contained neurotensin, recently identified in a variety of endocrine tumors. Argyrophil invasive carcinomas are a much more heterogeneous group of tumors than argyrophil DCIS and only a minority have an endocrine structure comparable to that described here.