Renal Perivascular Epithelioid Cell Tumors [(PEComa), so Called Epithelioid Angiomyolipoma (EAML)]: Analysis of 61 Cases Including 44 with Pure/Predominant Epithelioid (P-PEComa) Morphology and Parameters Associated with Malignant Outcome
N Nese, G Martignoni, CD Fletcher, R Gupta, CC Pan, H Kim, K Sato, F Bonetti, M Pea, M Amin, O Hes, A Svec, MB Amin. Cedars-Sinai Med Center, Los Angeles; Celal Bayar Univ, Manisa, Turkey; Universita'di Verona, Verona, Italy; Dana-Farber/Harvard Med School, Boston; Taipei Veterans General Hosp, Taipei, Taiwan; Roswell Park Cancer Inst, Buffalo; Kanazawa Univ, Ishikawa, Japan; William Beaumont Hosp, Detroit; Univ Hosp Plzen, Plzen, Czech Republic; Charles Univ, Prague, Czech Republic
Background: There are 109 published cases of renal EAML or malignant AML or PEComas, mostly as case reports or small series. Metastasis or death is reported in 54% of cases. Criteria predicting malignancy are unknown.
Design: Clinicopathologic features of 61 cases (44 P-PEComas >80% epithelioid morphology (EM) and 17 mixed PEComas with 10 to 80% EM along with AML histology) were analyzed to identify features associated with malignancy.
Results: The results of the survival analysis for various clinicopathologic parameters in P-PEComas and mixed PEComa are tabulated below. The EM displayed 3 patterns: diffuse large discohesive epithelioid cells with eosinophilic cytoplasm and frequent multinucleation (46%); carcinoma like growth of cohesive cells with clear/eosinophilic cytoplasm or sarcomatous growth of atypical malignant spindle cells (31%) and; EM admixed with spindle cells (23%); multiple patterns were often seen in a case.
|Clinicopathological Parameters||P-PEComa (n=44)||Mixed PEComa (n=17)||p value for survival|
|Mean Age||41||51||0.001 (favorable for age < 20)|
|Presence of Tuberous Sclerosis||46.4%||60%||0.6|
|Mean T size||11.2 cm||6.3 cm||0.001 (for size>7 cm)|
|Carcinoma-like or sarcomatous growth||56.3%||11.1%||0.6|
|Mitosis||8.1%||0%||0.001 (for >5/10hpf)|
|Mean follow-up (mo)||50||45|
|Disease progression||51.9%||18.2%||0.02 (for P vs. Mixed)|
Conclusions: Unlike PEComas at other sites, renal tumors are often associated with triphasic AML histology. Almost 40% of renal PEComas have malignant potential; tumors with P-PEComa histology, those greater than 7 cm, with perinephric extension and with significant mitotic activity are associated with malignant outcome.
Category: Genitourinary (including renal tumors)
Monday, March 9, 2009 8:00 AM
Platform Session: Section A, Monday Morning