Immunohistochemical examination of an orbital alveolar soft part sarcoma.
BACKGROUND
A 32 year-old male patient had a 6-week history of left-sided proptosis. Computer tomography revealed a 16x15x15 mm smooth and well-defined mass between the optic nerve and the medial and superior rectus muscles in the left orbit.


METHODS
The tumour was excised via a cranio-medial orbitotomy approach.


RESULTS
Histopathological examination, immunohistochemistry and electron microscopy findings were consistent with an alveolar soft part sarcoma. Immunohistochemical staining showed positive immunoreactivity for neuronespecific enolase, vimentin, p53 (30%), p21 (10%) and cyclin D1 (20%), and negative immunoreactivity for CD45, cytokeratins, S-100 protein, glial fibrillary acidic protein, synaptophysin, chromogranin, calcitonin, serotonin, thyreoglobulin, desmin, myosin, actin, HMB-45, pRB, p16 and BCL-2. The growth fraction of the tumour cells was 3%. At examination 4 years after surgical excision, there was no evidence of local recurrence or for metastases.


CONCLUSIONS
Alveolar soft part sarcoma of the orbit is a rare malignant tumour best controlled by surgery. The unpredictable behaviour of these neoplasms, however, indicates the need for long-term follow-up.
Coupland
S E
SE
Pathology Department, Universitätsklinikum Benjamin Franklin, Berlin, Germany.
Heimann
H
H
Hoffmeister
B
B
Lee
W R
WR
Foerster
M H
MH
Gross
U
U
D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D003937:Diagnosis, Differential; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D009918:Orbital Neoplasms / Q000737:chemistry* / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D010751:Phosphopyruvate Hydratase / Q000032:analysis*; D018234:Sarcoma, Alveolar Soft Part / Q000737:chemistry* / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D014057:Tomography, X-Ray Computed; D016159:Tumor Suppressor Protein p53 / Q000032:analysis*; D014746:Vimentin / Q000032:analysis*
D014408:Biomarkers, Tumor; D016159:Tumor Suppressor Protein p53; D014746:Vimentin; D010751:Phosphopyruvate Hydratase