Adenocarcinoid is a form of appendiceal carcinoid possessing features of both carcinoid and adenocarcinoma. There are two histologic types. Thirty patients had the goblet cell type, characterized by nests of large mucin-distended cells. Nine patients had the tubular type, characterized by small glandular structures lined by uniform cells. Despite abundant mucin and a goblet cell or acinar-like arrangement, a closer relationship to carcinoid than to adenocarcinoma is suggested by a concentration of tumor elements below the crypts of Lieberkuhn, a lack of evidence of neoplastic transformation of the appendiceal mucosa, and the demonstration of argentaffin or argyrophil granules in 88% of the lesions. Six tumors, all of the goblet cell type, metastasized and resulted in the death of the patients. One of the tumours that metastasized had a prominent tubular component. Most adenocarcinoids can be adequately treated by appendectomy, but hemicolectomy is recommended for those tumors showing atypical foci, a high mitotic count, or spread beyond the appendix.
Apocrine tumors from the axilla of 12 patients were studied clinically and pathologically. Based on histologic features, two tumors were classified as adenomas and ten as adenocarcinomas. All of the neoplasms were characterized by a glandular arrangement of large cells with abundant eosinophillic cytoplasm and evidence of decapitation secretion. The cytoplasm of the tumor cells contained PAS-positive, diastase-resistant granules. Intracytoplasmic particles of iron were demonstrable in three of ten tumors. Follow-up was available for all 12 patients. The two patients with apocrine adenoma are alive and well. Two patients with adenocarcinoma died of unrelated causes shortly after diagnosis. Of the remaining eight patients with adenocarcinoma, three have died of disease, and one is living with skeletal metastasis. A correlation appears to exist between tumor differentiation and prognosis.
Two examples of the goblet cell form of adenocarcinoid were studied with electron microscopy. Mucin was present in the form of large and small vacuoles or small patches of denser mucin granules. A small population of cells had a complement of organelles similar to the more obvious goblet cells but contained little or no identifiable product. Enterochromaffin cells were similar to those seen in normal midgut and in conventional carcinoids of midgut derivation. Enterochromaffin granules and mucin were not mixed with one another. Cell types transitional between mucinous and enterochromaffin were not found. Although study of plasmalemmae was hindered to a degree by artifacts due to tengential sectioning and, possibly, insufficiently rapid fixation, we favor the interpretation that the goblet cell type of adenocarcinoid is composed of two separate classes of cells.
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