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2013, Volume 29, Number 3, Page(s) 221-226
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DOI: 10.5146/tjpath.2013.01181 |
Spindle Cell Rhabdomyosarcoma Displaying CD34 Positivity: A Potential Diagnostic Pitfall; Report of Two Pediatric Cases |
Ayper KAÇAR1, Hacı Ahmet DEMİR2, Haydar DURAK3, Sergülen DERVİŞOĞLU3 |
1Department of Pathology, Ankara Child Health and Diseases Hematology Oncology Training and Research Hospital, ANKARA, TURKEY
2Department of Oncology, Ankara Child Health and Diseases Hematology Oncology Training and Research Hospital, ANKARA, TURKEY
3Department of Pathology, İstanbul University, Cerrahpaşa Faculty of Medicine, İSTANBUL, TURKEY |
Keywords:
Rhabdomyosarcoma, Antigens, CD34, Differential diagnosis |
Spindle cell rhabdomyosarcoma is a rare subtype of rhabdomyosarcoma
mainly seen in children. Occasional aberrant staining with
a variety of immunohistochemical markers has been noted. The
aberrantly expressed markers include alpha-smooth muscle actin,
cytokeratin, S100, neurofilaments, CD20, immunoglobins, and CD117.
We report herein two pediatric cases displaying strong CD34
positivity and one with additional focal CD117 positivity, causing
considerable difficulty in distinction from solitary fibrous tumor and
extra-gastrointestinal stromal tumor.
To our knowledge, CD34 staining has been merely reported in
rhabdomyosarcoma. Spindle cell rhabdomyosarcoma has to be
considered in the differential diagnosis of childhood spindle cell
tumors. Post-chemotherapy specimens should be evaluated in
caution, since chemotherapy can cause considerable changes in
tumor antigen expression. Since CD117 and CD34 are stem cell
markers, their positivity in pediatric tumors should be interpreted
with caution. Even if the morphology is not supportive, a wide
immunohistochemical panel should be applied in childhood
malignant solid tumors.
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