Utility of a comprehensive immunohistochemical panel in the differential diagnosis of spindle cell lesions of the urinary bladder.
ABSTRACT Spindle cell lesions of the urinary bladder are uncommon, but when encountered in clinical practice, pose a difficult diagnostic challenge as the differential diagnostic considerations are vast. Pseudosarcomatous processes significantly overlap with malignant tumors (sarcomatoid urothelial carcinoma and leiomyosarcoma) in their morphology and published immunohistochemical profile [pancytokeratin pan (CK), smooth muscle actin (SMA), and desmin]. p63 has been studied rarely and CK 5/6 and CK 34betaE12 have not been analyzed in the bladder in this diagnostic context. In the current study, 45 typical examples of spindle cell lesions [10 pseudosarcomatous myofibroblastic proliferations (PMP), 22 sarcomatoid urothelial carcinomas, and 13 smooth muscle tumors] of the urinary bladder were immunostained with a panel containing broad spectrum anticytokeratin antibodies (OSCAR or AE1/AE3), as well as antibodies to CK 34betaE12, CK 5/6, p63, SMA, and anaplastic lymphoma kinase (ALK). The immunoreactivity was as follows: PMP-CK (OSCAR) 7/10 (70%), CK (AE1/AE3) 7/9 (78%), CK 34betaE12 0/10 (0%), CK 5/6 0/9 (0%), p63 0/9 (0%), SMA 10/10 (100%), ALK 2/10 (20%); sarcomatoid urothelial carcinoma-CK (OSCAR) 15/22 (68%), CK (AE1/AE3) 14/20 (70%), CK 34betaE12 5/20 (25%), CK5/6 6/22 (27%), p63 11/22 (50%), SMA 16/22 (73%), ALK 0/22 (0%); and smooth muscle tumors-CK (OSCAR) 7/13 (54%), CK (AE1/AE3) 7/12 (58%), CK 34betaE12 0/12 (0%), CK 5/6 0/12 (0%), p63 3/13 (23%), SMA 11/13 (85%), ALK 0/13 (0%). Positivity for keratin was typically focal to moderate in smooth muscle tumors and more commonly moderate to diffuse in sarcomatoid carcinomas and PMP. Our data indicate that there is significant immunohistochemical overlap between the different spindle cell lesions, each of which has unique clinicopathologic, prognostic, and therapeutic ramifications. Within the context of morphology, an immunohistochemical panel composed of broad-spectrum antibodies to cytokeratin as well as antibodies to SMA, ALK, p63, and CK 5/6 will be a useful diagnostic adjunct: a combination of pankeratin, SMA, and ALK positivity favors PMP; expression of several cytokeratin and especially CK 34betaE12 and CK 5/6 with p63 favors sarcomatoid carcinoma and SMA positivity with overall absence of other markers favors leiomyosarcoma.
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ABSTRACT: We illustrate a case of an inflammatory myofibroblastic tumor (IMT) involving the bladder in a woman with dysuria and review the literature and differential diagnosis. Inflammatory myofibroblastic tumor, also referred to as pseudosarcomatous myofibroblastic proliferation, is a rare lesion that can arise in the genitourinary system and is characterized by a fascicular arrangement of myofibroblasts with admixed inflammatory cells and slitlike vessels. Urinary bladder IMT can be a diagnostic pitfall because its histologic features (brisk mitoses, invasion into muscularis propria, and prominent nucleoli) can mimic malignancy. The differential diagnosis of urinary bladder IMT includes sarcomatoid carcinoma and leiomyosarcoma. Diagnostic features such as bland nuclear chromatin, ganglion-like cells, pale eosinophilic cytoplasm with long processes, overexpression of anaplastic lymphoma kinase (immunohistochemistry or gene rearrangement studies), and the absence of atypical mitoses help distinguish IMT from its malignant mimics. Current controversies regarding postoperative spindle cell nodule and IMT are discussed.Archives of pathology & laboratory medicine 10/2014; 138(10):1272-1277. DOI:10.5858/arpa.2014-0274-CC · 2.88 Impact Factor
Saudi medical journal 02/2015; 36(3):363-5. DOI:10.15537/smj.2015.3.10149 · 0.55 Impact Factor
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ABSTRACT: Data on immunohistochemical expression of novel and traditional urothelial markers in the wide range of urothelial carcinoma variants has so far been very limited. In this study, whole tissue sections from 130 bladder urothelial carcinoma and variants were stained with a panel of novel and traditional immunomarkers supportive of urothelial lineage. The positivity rates were as follows: a) urothelial carcinomas with or without divergent differentiation: GATA3 (50%), S100P (86%), uroplakin III (20%), thrombomodulin (40%), CK7 (80%), CK20 (55%), p63 (87%) and HMCK (89%); b) urothelial carcinoma variants (micropapillary, plasmacytoid, nested, clear cell and microcystic): GATA3 (88%), S100P (96%), uroplakin III (33%), thrombomodulin (49%), CK7 (95%), CK20 (61%), p63 (69%) and HMCK (96%); and c) undifferentiated carcinomas (LELC, small cell carcinoma, sarcomatoid carcinoma and carcinoma with rhabdoid and giant cells): GATA3 (28%), S100P (31%), uroplakin III (0%), thrombomodulin (22%), CK7 (50%), CK20 (3%), p63 (50%) and HMCK (49%). In urothelial carcinoma with squamous differentiation, GATA3 expression was lower (20%) in contrast to p63 and S100P. In urothelial carcinoma with glandular differentiation, GATA3 (50%) and p63 (60%) expression was lower than S100P (100%). p63 expression was relatively lower in micropapillary (54%) and plasmacytoid (50%) variants compared to the other urothelial carcinoma variants. This study provides a comprehensive data for novel and traditionally used markers to support urothelial lineage in urothelial carcinoma variants. Our findings show that GATA3, S100P, CK7, CK20, HMCK and p63, in the appropriate differential diagnostic setting, are useful to support urothelial lineage of variant morphologies.Human pathology 07/2014; 45(7). DOI:10.1016/j.humpath.2014.02.024 · 2.81 Impact Factor