title: Variant of prostatic adenocarcinoma with Paneth cell-like neuroendocrine differentiation readily misdiagnosed as Gleason pattern 5.
abstract: This study focused on 11 cases of prostatic adenocarcinoma with Paneth cell-like change, which had sparse to no Paneth cell-like granules; grading the tumor conventionally would have resulted in assigning a Gleason pattern 5 for the primary or secondary pattern. Ten cases were entirely composed of the Paneth cell-like component. Architectural patterns included the following: nest and cord-like architecture (n = 4; 36.4%), nests only (n = 6; 54.5%), and cords only (n = 1; 9.1%). All 11 cases had amphophilic cytoplasm. Among the 11 cases, 7 had rare granules, 1 had 10% of the cells with granules, and 3 had no granules. Within the Paneth cell-like feature component, rare nucleolar prominence was seen in only 4 (36.4%) of 11 cases. Eight cases were diffusely positive for chromogranin and synaptophysin, 2 for chromogranin only, and 1 for synaptophysin only. In the 3 cases where performed, Ki-67 showed a very low rate of less than 5%. The keys to recognizing these cases are as follows: (1) nests and cords in a small focus, (2) deeply amphophilic cytoplasm with careful search in most cases revealing rare Paneth cell-like eosinophilic granules, (3) indistinct nucleoli, and (4) immunohistochemical staining for neuroendocrine markers. Based on follow-up from prior studies and the current work, these tumors appear to have a favorable prognosis. The importance of recognizing this variant of adenocarcinoma with Paneth cell-like differentiation is that if these tumors were graded conventionally, 9 of the 11 cases would have been assigned a misleading Gleason score of 5 + 5 = 10 or 5 + 4 = 9.
authors.affiliation: Department of Pathology, the Johns Hopkins Medical Institutions, Baltimore, MD 21231.
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: So
authors.affiliation: Department of Pathology, the Johns Hopkins Medical Institutions, Baltimore, MD 21231.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Gordetsky
authors.affiliation: Department of Pathology, the Johns Hopkins Medical Institutions, Baltimore, MD 21231; Department of Urology, the Johns Hopkins Medical Institutions, Baltimore, MD 21231; Department of Oncology, the Johns Hopkins Medical Institutions, Baltimore, MD 21231. Electronic address: jepstein@jhmi.edu.
authors.forename: Jonathan I
authors.initials: JI
authors.lastname: Epstein
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology*; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D002864:Chromogranins / Q000378:metabolism; D003951:Diagnostic Errors; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D019879:Paneth Cells / Q000378:metabolism / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D016708:Synaptophysin / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D002864:Chromogranins; D016708:Synaptophysin
keywords: Gleason grade; Neuroendocrine differentiation; Paneth cell; Prostate adenocarcinoma