Soft tissue
Perivascular epithelioid cell
PEComa - falciform ligament / ligamentum teres

Author: Vijay Shankar, M.D. (see Authors page)

Revised: 22 September 2016, last major update November 2012

Copyright: (c) 2002-2016,, Inc.

PubMed Search: Falciform ligament / ligamentum teres

Cite this page: PEComa - falciform ligament / ligamentum teres. website. Accessed October 24th, 2016.
Definition / General
  • Usually females, median age 11 years, range 3 - 21 years
Case Reports
Gross Description
  • Median 8 cm, range 5 - 20 cm
Micro Description
  • Fascicular or nested groups of spindle cells (usually no epithelioid cells) with lightly eosinophilic, fibrillar cytoplasm with cytoplasmic clearing and small but distinct nucleoli in delicate capillary network similar to renal cell carcinoma
  • Rare mitotic figures
  • No necrosis, no angiolymphatic invasion
Positive Stains
Negative Stains
Differential Diagnosis
  • Angiomyolipoma: thick walled blood vessels, lipid distended tumor cells, spindled cells
  • Cellular schwannoma: true capsule, thick-walled hyalinized blood vessels, strong S100 staining
  • Clear cell sarcoma of tendons and aponeuroses: epithelioid and spindled areas with tumor giant cells, S100+, positive for melanocytic markers but negative for smooth muscle actin and myosin; t(12,22) present
  • Leiomyoma: distinctly eosinophilic, cigar-shaped nuclei with blunt ends and perinuclear vacuoles; thick walled blood vessels
  • Leiomyosarcoma: large deep seated mass with obvious nuclear pleomorphism and mitotic activity, often with necrosis; negative for HMB45, MelanA, microphthalmic transcription factor, positive for desmin