PEComa: another member of the MiT tumor family?
We report 2 cases of PEComa, one occurring in the colon of an 11-year-old boy and the other in the bone (fibula) of a 92-year-old woman. Both tumors consisted of nests of large epithelioid cells surrounded by a fibrovascular stroma. The nuclei were large and vesicular, with prominent centrally located nucleoli. The cytoplasm was eosinophilic, with a fine to coarse granularity. Mitoses and individual cell necrosis were infrequent. Immunohistochemically, both tumors showed strong cytoplasmic expression of HMB-45 and intense nuclear positivity for TFE3. To our knowledge, nuclear positivity for TFE3 has been previously reported in only 5 cases of PEComa. Reactivity to this marker suggests that PEComa should be added to the growing list of human tumors of the so-called MiT family gene.
Righi
Alberto
A
Centro Diagnostico Italiano, Anatomic Pathology, University of Bologna, Bellaria Hospital, Italy. alberto.righi@gmail.com
Dimosthenous
Kypros
K
Rosai
Juan
J
D000369:Aged, 80 and over; D000951:Antigens, Neoplasm; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000096:biosynthesis; D001859:Bone Neoplasms / Q000378:metabolism / Q000473:pathology*; D001943:Breast Neoplasms / Q000473:pathology; D002648:Child; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology*; D015622:Epithelioid Cells / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D058950:Melanoma-Specific Antigens; D051739:Microphthalmia-Associated Transcription Factor / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000096:biosynthesis; D016609:Neoplasms, Second Primary / Q000473:pathology
D000951:Antigens, Neoplasm; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; C497234:MITF protein, human; D058950:Melanoma-Specific Antigens; D051739:Microphthalmia-Associated Transcription Factor; D009363:Neoplasm Proteins; C069203:TFE3 protein, human