[840] 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) |
| Gender (M:F) | 0.8:1 | 1:7 | 0.8 |
| Presence of Tuberous Sclerosis | 46.4% | 60% | 0.6 |
| Associated AML | 50% | 38.5% | 0.04 |
| 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 |
| Perinephric spread | 42% | 15% | 0.001 |
| Necrosis | 65% | 40% | 0.03 |
| 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