title: Primary renal carcinoid tumors: clinicopathologic features of 9 cases with emphasis on novel immunohistochemical findings.
abstract: Primary renal carcinoid tumors are rare neoplasms. Because of the rarity of these neoplasms, clinicopathologic and immunohistochemical characteristics have not been fully characterized. Immunohistochemistry for renal cell lineage transcription factors, such as paired box gene 2 and paired box gene 8, has not been studied in renal carcinoid tumors and may be useful in demonstrating nephrogenic differentiation. We studied the clinical, morphological, and immunohistochemical features in 9 primary renal carcinoid tumors from multiple institutions with particular emphasis on immunohistochemical findings, in particular, expression of paired box gene 2 and paired box gene 8. All 9 cases expressed at least 1 neuroendocrine marker (CD56, synaptophysin, chromogranin). The renal-associated (paired box gene 2/paired box gene 8), gastrointestinal (caudal-related homeobox-2), and pulmonary/thyroid (thyroid transcription factor-1) transcription factors were not expressed in renal carcinoids (0/9). Of interest, CD99 was expressed in 8 of 9 cases, with the one negative case representing an atypical carcinoid. Perinephric extension and nodal and distant metastases are common. The absence of expression of paired box gene 2 and paired box gene 8, although not conclusive, supports the theory that these are derived from nonnephrogenic elements. CD99 was expressed in almost all cases (8/9); recognition of this could prevent misdiagnosis of a renal primitive neuroectodermal tumor.
authors.affiliation: Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL 32610, USA.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Jeung
authors.forename: Dengfeng
authors.initials: D
authors.lastname: Cao
authors.forename: Belinda W
authors.initials: BW
authors.lastname: Selli
authors.forename: William L
authors.initials: WL
authors.lastname: Clapp
authors.forename: Bahram R
authors.initials: BR
authors.lastname: Oliai
authors.forename: Anil V
authors.initials: AV
authors.lastname: Parwani
authors.forename: Robert W
authors.initials: RW
authors.lastname: Allan
mesh_terms: D000328:Adult; D000368:Aged; D002276:Carcinoid Tumor / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007680:Kidney Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D051762:PAX2 Transcription Factor / Q000378:metabolism; D000072636:PAX8 Transcription Factor; D051761:Paired Box Transcription Factors / Q000378:metabolism
chemical_list: D051762:PAX2 Transcription Factor; D000072636:PAX8 Transcription Factor; C083325:PAX8 protein, human; D051761:Paired Box Transcription Factors