Mucinous Carcinoid as an Unusual Manifestation of Endodermal Differentiation in Ovarian Yolk Sac TumorsNogales, Francisco F MD*; Buriticá, Catalina MD*; Regauer, Sigrid MD†; González, Talina MD*The American Journal of Surgical Pathology: September 2005 - Volume 29 - Issue 9 - p 1247-1251 doi: 10.1097/01.pas.0000161533.39478.a7 Case Report Buy Abstract Author InformationAuthors Article MetricsMetrics We present, for the first time, two yolk sac tumors (YST) in women 37 and 18 years of age, one with a typical parietovisceral pattern and the other with a glandular pattern, which were associated with extensive areas of mucinous carcinoid (MC). The tumor in the first case had numerous nodules of tubulopapillary YST that merged with well-differentiated MC. This patient responded well to chemotherapy. The tumor in the second case consisted of an AFP-positive glandular YST, with a glandulopapillary pattern closely resembling fetal lung type adenocarcinoma, coexisting with an AFP-negative, cytokeratin 20-positive, atypical MC; transitional areas between the two components were also seen. In the material from the recurrences and metastases; however, no YST was present, the atypical MC having become the predominant component including areas that had become carcinomatous. There was a poor response to various chemotherapeutic regimens. AFP levels became negative during the course of disease paralleling the disappearance of the YST component and the overgrowth of an increasingly anaplastic MC. The patient died 1 year after diagnosis. We think that, in these cases, MC represented an unusual form of endodermal differentiation of the YST. It is important to differentiate the yolk sac and carcinoid components due to their different responses to chemotherapy and to evaluate the possibility of mucinous carcinoid developing into a highly aggressive carcinoma. From the *Department of Pathology, University Hospital, Granada, Spain; and †Department of Pathology, Medical University of Graz, Graz, Austria. Reprints: Francisco F. Nogales, MD, Departamento de Anatomía Patológica, Facultad de Medicina, 18012 Granada, Spain (e-mail: email@example.com). © 2005 Lippincott Williams & Wilkins, Inc.