Solitary fibrous tumors are immunophenotypically distinct from mesothelioma(s).
BACKGROUND
Solitary fibrous tumor is a soft tissue tissue tumor of unknown histogenesis. Based upon histologic similarities and CD-34 expression, it has been suggested that these neoplasms bear some relationship to mesothelioma, and may represent its extra-pleural equivalent.


METHODS
In order to further investigate this possible relationship, we examined a series of five dermal and five extra-cutaneous solitary fibrous tumors with antibodies directed against the mesothelial markers calretinin and HBME-1.


RESULTS
All the lesions failed to stain with the antibodies tested. This suggests that despite some similar histologic and immunophenotypic features, these lesions are not immunophenotypically identical. Mesotheliomas are CD-34(+), calretinin(+), HBME-1(+), while solitary fibrous tumors are CD-34(+), calretinin(-), HBME-1(-).


CONCLUSIONS
The histogenesis of solitary fibrous tumor remains elusive. It is unlikely that tumor location or tumor de-differentiation accounts for the dichotomous staining properties, as these neoplasms show a similarly benign histologic appearance regardless of location.
Morgan
M B
MB
Department of Pathology, James Haley Veteran's Administration Hospital, Tampa, Florida, USA.
Smoller
B R
BR
D000328:Adult; D000368:Aged; D018952:Antigens, CD34 / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis; D064032:Calbindin 2; D005260:Female; D005350:Fibroma / Q000737:chemistry / Q000473:pathology*; D006801:Humans; D007124:Immunoenzyme Techniques; D016130:Immunophenotyping; D008297:Male; D008654:Mesothelioma / Q000737:chemistry / Q000473:pathology*; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis; D009918:Orbital Neoplasms / Q000737:chemistry / Q000473:pathology*; D012142:Respiratory Tract Neoplasms / Q000737:chemistry / Q000473:pathology*; D064030:S100 Calcium Binding Protein G / Q000032:analysis; D012878:Skin Neoplasms / Q000737:chemistry / Q000473:pathology*
D018952:Antigens, CD34; D014408:Biomarkers, Tumor; C576764:CALB2 protein, human; D064032:Calbindin 2; D009363:Neoplasm Proteins; D064030:S100 Calcium Binding Protein G