Alveolar soft-part sarcoma of the urinary bladder with urethral recurrence: a unique case with emphasis on differential diagnoses and diagnostic utility of an immunohistochemical panel including TFE3.
Alveolar soft-part sarcoma (ASPS) is a rare, clinically, morphologically, ultrastructurally, and cytogenetically distinctive malignant mesenchymal tumor that most classically occurs in the extremities of adolescents and young adults, but has also been described in a number of unusual sites. The molecular signature of ASPS is a specific der(17)t(X;17)(p11.2;q25) translocation, which results in the fusion of TFE3 transcription factor gene (from Xp11) with ASPL at 17q25. The ASPL-TFE3 fusion protein encoded by the fusion transcript can be detected immunohistochemically with commercially available antibodies to the carboxy terminus of TFE3. Herein, we report a unique case of ASPS presenting in the bladder with subsequent urethral recurrence in a 25-year-old woman. We emphasize the differential diagnoses engendered by ASPS including common, not-so-common, and rare tumors involving the urinary bladder that have a nested architecture, and both clear and eosinophilic cytoplasm, and demonstrate the utility of a broad immunohistochemistry panel including TFE3 for diagnosis.
Amin
Mahul B
MB
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA.
Patel
Rajiv M
RM
Oliveira
Pedro
P
Cabrera
Rafael
R
Carneiro
Victor
V
Preto
Mota
M
Balzer
Bonnie
B
Folpe
Andrew L
AL
D000328:Adult; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis; D003937:Diagnosis, Differential; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D009364:Neoplasm Recurrence, Local; D012509:Sarcoma / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D012983:Soft Tissue Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D014463:Ultrasonography; D014521:Urethra / Q000473:pathology*; D001749:Urinary Bladder Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D014408:Biomarkers, Tumor; C069203:TFE3 protein, human