TY - JOUR
T1 - Fibromyxoid nephrogenic adenoma
T2 - A newly recognized variant mimicking mucinous adenocarcinoma
AU - Hansel, Donna Elizabeth
AU - Nadasdy, Tibor
AU - Epstein, Jonathan I.
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2007/8
Y1 - 2007/8
N2 - Nephrogenic adenomas demonstrate a variety of morphologic patterns that may occasionally be confused with malignant processes, including urothelial and prostatic carcinoma. In this series, we describe 8 cases of nephrogenic adenoma that contain an admixture of the classic tubular form of nephrogenic adenoma and an unusual spindled and fibromyxoid form of nephrogenic adenoma that closely mimics infiltrating carcinoma. In all cases, the classic tubular form of nephrogenic adenoma composed only a small proportion of the lesion, whereas the remainder consisted of compressed spindled cells within a fibromyxoid background, with only rare tubular and cordlike structures. On close examination, minimal nuclear atypia was identified in 2 cases, which included small, pinpoint nucleoli, and nuclear pseudoinclusions. All 8 patients were elderly men who had a prior or concurrent history of acinar prostate cancer (n=4), combined acinar prostate and urothelial carcinoma (n=1), urothelial-type adenocarcinoma of the prostate (n=1), bladder urothelial carcinoma (n=1), or no prior reported prostatic or urothelial abnormalities (n=1). Five patients received prior treatment with radiotherapy, 1 patient received intravesical mitomycin-C, and 1 also received bacillus Calmette-Guerin. The epithelial component of the lesions was positive in all cases for pancytokeratin (AE1/3) and racemase and demonstrated a variable cuff of type IV collagen surrounding the tubules. PAX-2 was positive with variable extent of labeling. Immunostains for prostate-specific antigen were negative. Histochemical stains identified some of the background matrix as mucin, with intense staining for periodic acid-Schiff and focal staining for mucicarmine. Stains for reticulin and amyloid (Congo red stain) and immunohistochemistry for Tamm-Horsfall protein were negative. This case series is the first report of a fibromyxoid subtype of nephrogenic adenoma. Awareness of this entity and the use of ancillary techniques can aid in the diagnosis of this unusual form of nephrogenic adenoma.
AB - Nephrogenic adenomas demonstrate a variety of morphologic patterns that may occasionally be confused with malignant processes, including urothelial and prostatic carcinoma. In this series, we describe 8 cases of nephrogenic adenoma that contain an admixture of the classic tubular form of nephrogenic adenoma and an unusual spindled and fibromyxoid form of nephrogenic adenoma that closely mimics infiltrating carcinoma. In all cases, the classic tubular form of nephrogenic adenoma composed only a small proportion of the lesion, whereas the remainder consisted of compressed spindled cells within a fibromyxoid background, with only rare tubular and cordlike structures. On close examination, minimal nuclear atypia was identified in 2 cases, which included small, pinpoint nucleoli, and nuclear pseudoinclusions. All 8 patients were elderly men who had a prior or concurrent history of acinar prostate cancer (n=4), combined acinar prostate and urothelial carcinoma (n=1), urothelial-type adenocarcinoma of the prostate (n=1), bladder urothelial carcinoma (n=1), or no prior reported prostatic or urothelial abnormalities (n=1). Five patients received prior treatment with radiotherapy, 1 patient received intravesical mitomycin-C, and 1 also received bacillus Calmette-Guerin. The epithelial component of the lesions was positive in all cases for pancytokeratin (AE1/3) and racemase and demonstrated a variable cuff of type IV collagen surrounding the tubules. PAX-2 was positive with variable extent of labeling. Immunostains for prostate-specific antigen were negative. Histochemical stains identified some of the background matrix as mucin, with intense staining for periodic acid-Schiff and focal staining for mucicarmine. Stains for reticulin and amyloid (Congo red stain) and immunohistochemistry for Tamm-Horsfall protein were negative. This case series is the first report of a fibromyxoid subtype of nephrogenic adenoma. Awareness of this entity and the use of ancillary techniques can aid in the diagnosis of this unusual form of nephrogenic adenoma.
KW - Bladder
KW - Mucin
KW - Prostate carcinoma
KW - Spindle cell
KW - Urothelial carcinoma
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UR - http://www.scopus.com/inward/citedby.url?scp=34547647034&partnerID=8YFLogxK
U2 - 10.1097/PAS.0b013e31802e290d
DO - 10.1097/PAS.0b013e31802e290d
M3 - Article
C2 - 17667548
AN - SCOPUS:34547647034
SN - 0147-5185
VL - 31
SP - 1231
EP - 1237
JO - American Journal of Surgical Pathology
JF - American Journal of Surgical Pathology
IS - 8
ER -