We presented four patients (3 women, 1 man; mean age 40 years; range 20 to 56 years) who had alveolar soft part sarcoma in the left arm, right elbow, right tibia, and left thigh, respectively. All the patients presented with a mass. Two patients had lung metastasis at the time of diagnosis. T1- and T2-weighted magnetic resonance images of all the patients showed a soft tissue lesion with hyperintense signal changes and heterogeneous contrast enhancement. Diagnoses were made by histopathologic examination of biopsy samples. All the patients received chemotherapy. Surgical resection was performed in three patients. Two patients with involvement of the left arm and right elbow died within three years after diagnosis. One patient with involvement of the left thigh developed lung and brain metastases at the end of postoperative eight years. One patient with tibial involvement remained disease-free during 10 months of follow-up.

Immunohistochemical discrimination between the ASPL-TFE3 fusion proteins of alveolar soft part sarcoma. J Pediatr Hematol Oncol. 2008 Jan;30(1):46-52.

Alveolar soft part sarcoma (ASPS), a rare soft tissue sarcoma, is characterized by a chromosomal translocation der(17)t(X;17)(p11;q25) resulting in the production of 2 fusion proteins encoded by regions of the genes for alveolar soft part locus (ASPL) and the transcription factor E3 (TFE3). In this study, polyclonal antibodies were generated to 25 mer peptides encompassing the junctional regions of ASPL-TFE3 type 1 and ASPL-TFE3 type 2. The specificity of the affinity purified antibodies for the synthetic peptides and recombinant expressed ASPL-TFE3 type 1 and ASPL-TFE3 type 2 proteins was evaluated by enzyme-linked immunosorbent assay and was highly fusion type specific. Immunohistochemical staining of formalin-fixed, paraffin-embedded ASPS tumors with the fusion-specific antibodies resulted in intense nuclear staining and differentiation between tumors that express the type 1 protein and tumors that express the type 2 protein. These antibodies will be useful for the differential diagnosis of type 1 and type 2 ASPS and also in the detection of the fusion proteins in biochemical and cell biologic investigations.