Primary Carcinoid Tumor of the Renal Pelvis Arising From Intestinal Metaplasia: An Unusual Histogenetic Pathway?

OBJECTIVES: Primary carcinoid tumor of the renal pelvis is a rare neoplasm with few cases reported in the literature. Here we present the clinical and histopathologic findings of a primary carcinoid tumor arising in the left renal pelvis of a horseshoe kidney in a 61-year-old female patient. MATERIALS AND METHODS: Pathologic features were evaluated with standard hematoxylin and eosin sections and immunohistochemical studies. A literature review was performed to place our case in context to previous reports. RESULTS: The tumor was associated with intestinal metaplasia with high-grade dysplasia and neuroendocrine hyperplasia. Molecular testing for microsatellite instability and loss of heterozygosity were negative. CONCLUSIONS: This report portrays a unique presentation of carcinoid tumor arising from intestinal metaplasia of the pelvic urothelium, and supports its histogenesis from urothelial intestinal metaplasia and neuroendocrine hyperplasia.

Limited utility of fluorescence in situ hybridization for common abnormalities of myelodysplastic syndrome at first presentation and follow-up of myeloid neoplasms.

Fluorescence in situ hybridization for abnormalities common to myelodysplastic syndrome (MDS FISH) is often used with traditional karyotype in the diagnosis and monitoring of myeloid neoplasms. However, its value in these roles has been questioned. To evaluate its utility, we compared MDS FISH results with karyotype in 544 bone marrow specimens obtained for diagnosis (180 cases) or follow-up (364 cases) of myeloid neoplasia. We found excellent concordance between FISH and karyotype, such that FISH is rarely abnormal (1.7% at diagnosis and 3.0% at follow-up) in cases with normal karyotype. Even in the rare discordant cases, the abnormal FISH has little or no clinical value. Thus, we propose that this test should be limited to cases with inadequate karyotype only. Such guidelines could result in significant cost savings with no impact on patient diagnosis.