title: Pigmented perivascular epithelioid cell tumor (PEComa) arising from kidney: A case report.
abstract: BACKGROUND
  Perivascular epithelioid cell tumor (PEComa) is a mesenchymal neoplasm composed of perivascular epithelioid cells with clear to eosinophilic cytoplasm. Pigmented PEComa arising from kidney is extraordinarily rare and sometimes can exhibit aggressive biological behavior.
  
  
  METHODS
  We present here a rare case of pigmented renal PEComa in a 46-year-old female. The patient had complained of lumbago complicated with nausea and vomiting for 2 weeks and therefore was referred to our department. An enhanced computed scan revealed a 4 × 3 × 3 cm round-like mass in the lower pole of right kidney with inhomogeneous enhancement. The tumor cells immunestained was positive for HMB-45, focally positive for c-Kit (CD117), and negative for vimentin, S-100, AE1/AE3, CK-7, CK-18, CD-10, RCC antigen, CgA, DOG-1, EMA, smooth muscle actin, and synaptophysin. We successfully performed 3-dimensional laparoscopic resection of the neoplasm, which was then diagnosed as pigmented PEComa by postoperative pathology. No further growing lesion or metastasis was observed during a 1-year follow-up.
  
  
  CONCLUSIONS
  This case report shows that pigmented renal PEComa is often presented as a renal mass with nonspecific symptoms and imaging features. The gold diagnosis of renal pigmented PEComa is mainly based on the combination of histopathology and immunohistochemistry. Complete resection by 3-dimensional laparoscopic nephron-sparing surgery can be an effective therapeutic management.
authors.affiliation: Department of Urology, the First Affiliated Hospital of Anhui Medical University and Institute of Urology, Anhui Medical University, Hefei, Anhui, China.
authors.forename: Hexi
authors.initials: H
authors.lastname: Du
authors.forename: Jun
authors.initials: J
authors.lastname: Zhou
authors.forename: Lingfan
authors.initials: L
authors.lastname: Xu
authors.forename: Cheng
authors.initials: C
authors.lastname: Yang
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Chaozhao
authors.initials: C
authors.lastname: Liang
mesh_terms: D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis / Q000601:surgery; D008875:Middle Aged; D054973:Perivascular Epithelioid Cell Neoplasms / Q000175:diagnosis / Q000601:surgery