Whorling cellular perineurioma: A previously undescribed variant closely mimicking monophasic fibrous synovial sarcoma.
The authors present a distinctive perineurioma (PN) variant which morphologically strongly resembles monophasic fibrous synovial sarcoma (MSS). The patients were 3 males and 1 female. The age ranged from 15 to 61years (mean: 44years). Locations included the sole, lower jaw, palm and foot. The tumor size ranged from 1.3cm to 2.5cm in the largest dimension (mean 1.8cm). Morphologically, all tumors had an identical, monotonous appearance. The perineurial cells were closely packed and created a confluent cellular whorls and/or sheets in a scarce stroma, with only focally discernible long, slender cytoplasmic processes typical for perineurial differentiation. The nuclei were rounded or slightly elongated to tapered, without nuclear atypia. Mitoses were rare to completely absent. Atypical mitoses, hemorrhage, necrosis or calcifications were not present. The proliferative index (Ki-67) was 1-3%. All analyzed tumors were positive for EMA, Claudin-1, GLUT-1 and negative with S100 protein, CD34, OSCAR, CK7 and TLE-1. Two cases were tested by fluorescence in situ hybridization and neither showed alterations of the SYT gene. One case studied by electron microscopy showed characteristic features of perineurial differentiation. Follow-up was available for two patients both of which showed no evidence of disease at 8years and 6months, respectively. Based on their bland morphology, perineurial features and presumably benign clinical outcome we propose the term "whorling cellular perineurioma" for these tumors, which may represent an extremely cellular variant of sclerosing PN. Awareness of this PN subtype and its distinction from MSS is of utmost clinical significance.
Department of Pathology, Faculty of Medicine in Pilsen, Charles University, Alej Svobody 80, 304 60 Pilsen, Czech Republic; Biomedical Center of the Faculty of Medicine in Pilsen, Alej Svobody 80, 304 60 Pilsen, Czech Republic. Electronic address: michael.michal@medima.cz.
Michael
M
Michal
Department of Pathology, Faculty of Medicine in Pilsen, Charles University, Alej Svobody 80, 304 60 Pilsen, Czech Republic.
Dmitry V
DV
Kazakov
Institute of Pathology, Friedrich-Alexander University Erlangen-Nürnberg, University Hospital, Krankenhausstrasse 8-10, 910 54, Erlangen, Germany.
Abbas
A
Agaimy
Department of Pathology, Faculty Hospital, Budínova 67/2, 180 81 Prague, Czech Republic.
Marta
M
Hosova
Department of Pathology, Faculty of Medicine in Pilsen, Charles University, Alej Svobody 80, 304 60 Pilsen, Czech Republic.
Kvetoslava
K
Michalova
Department of Pathology, Faculty of Medicine in Pilsen, Charles University, Alej Svobody 80, 304 60 Pilsen, Czech Republic.
Petr
P
Grossmann
Department of Pathology, Faculty of Medicine in Pilsen, Charles University, Alej Svobody 80, 304 60 Pilsen, Czech Republic.
Petr
P
Steiner
Department of Pathology, Clinical Center, University of Sarajevo, Bolnička 25, 710 00 Sarajevo, Bosnia and Herzegovina.
Faruk
F
Skenderi
Department of Pathology, Clinical Center, University of Sarajevo, Bolnička 25, 710 00 Sarajevo, Bosnia and Herzegovina; School of Medicine, Bolnička 25, 710 00 Sarajevo, Bosnia and Herzegovina.
Semir
S
Vranic
Department of Pathology, Faculty of Medicine in Pilsen, Charles University, Alej Svobody 80, 304 60 Pilsen, Czech Republic.
Michal
M
Michal
D000328:Adult; D014408:Biomarkers, Tumor / Q000378:metabolism*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D008875:Middle Aged; D018317:Nerve Sheath Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D013584:Sarcoma, Synovial / Q000175:diagnosis / Q000473:pathology*
D014408:Biomarkers, Tumor
Monophasic fibrous synovial sarcoma; Sclerosing; Soft tissue; Whorling cellular perineurioma