RESUMEN
CONTEXT.: The Nottingham Grading System (NGS) developed by Elston and Ellis is used to grade invasive breast cancer (IBC). Glandular (acinar)/tubule formation is a component of NGS. OBJECTIVE.: To investigate the ability of pathologists to identify individual structures that should be classified as glandular (acinar)/tubule formation. DESIGN.: A total of 58 hematoxylin-eosin photographic images of IBC with 1 structure circled were classified as tubules (41 cases) or nontubules (17 cases) by Professor Ellis. Images were sent as a PowerPoint (Microsoft) file to breast pathologists, who were provided with the World Health Organization definition of a tubule and asked to determine if a circled structure represented a tubule. RESULTS.: Among 35 pathologists, the κ statistic for assessing agreement in evaluating the 58 images was 0.324 (95% CI, 0.314-0.335). The median concordance rate between a participating pathologist and Professor Ellis was 94.1% for evaluating 17 nontubule cases and 53.7% for 41 tubule cases. A total of 41% of the tubule cases were classified correctly by less than 50% of pathologists. Structures classified as tubules by Professor Ellis but often not recognized as tubules by pathologists included glands with complex architecture, mucinous carcinoma, and the "inverted tubule" pattern of micropapillary carcinoma. A total of 80% of participants reported that they did not have clarity on what represented a tubule. CONCLUSIONS.: We identified structures that should be included as tubules but that were not readily identified by pathologists. Greater concordance for identification of tubules might be obtained by providing more detailed images and descriptions of the types of structures included as tubules.
RESUMEN
Gastrointestinal stromal tumor (GIST) is one of the most common spindle cell neoplasms of the alimentary system, and can arise anywhere along the gastrointestinal tract (GI). Its incidence rate is up to 22 cases per million, with a minor geographic variation. GIST is thought to originate from interstitial cell of Cajal, and its pathogenesis is related to molecular defects, such as KIT receptor tyrosine kinase or platelet-derived growth receptor alpha gene activation. While the majority of GISTs are known to show a benign disease course, metastases of high-grade forms to different organ systems have been seldom reported. We present a case with an unprecedented metastasis of GIST to the breast. The patient is a 62-year-old female with a history of the primary resection of GIST from the small intestine. Her disease course was initially complicated by multiple metastases, solely localized to the liver for which she had a living-donor liver transplant. The tumor harbored both KIT exon 11 and exon 17 mutation. Fourteen months post-transplant, the patient was found to have metastatic GIST on her breast biopsy. GIST metastasis to the breast is extremely rare. A consideration of this spindle cell neoplasm as a differential is recommended when clinical suspicion arises. The pathophysiology, current diagnostic tool, grading system, and treatment of this tumor are discussed.