# Perivascular epithelioid cell tumour (PEComa)

Source: https://onco.cc/cancers/pecoma/  
OnCo record `pecoma` (Cancer). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

PEComa is a rare tumour of cells that sit around blood vessels and share features of muscle and pigment cells. Most are benign, but malignant ones spread and resist chemotherapy. They usually have lost the TSC1 or TSC2 brake on the growth signal mTOR, and in 2021 the mTOR blocker nab-sirolimus became the first approved treatment.

## Summary

Perivascular epithelioid cell tumours express both smooth muscle and melanocytic markers (HMB-45, Melan-A) and include renal angiomyolipoma, pulmonary lymphangioleiomyomatosis and clear cell sugar tumour of the lung as well as PEComa not otherwise specified of the uterus, retroperitoneum, gastrointestinal tract and soft tissue. Most carry biallelic loss of TSC1 or TSC2, with or without tuberous sclerosis complex, which unleashes mTOR signalling; a minority instead carry TFE3 fusions and do not respond to mTOR inhibition. Malignancy is predicted by size over five centimetres, infiltrative growth, high grade, necrosis, mitotic count and vascular invasion.

Complete surgical resection is the treatment for localised tumours, with no established role for adjuvant therapy, and surveillance for those with high-risk features. Conventional chemotherapy has little activity in malignant PEComa. Case series of sirolimus, everolimus and temsirolimus showed responses in TSC-altered tumours, establishing mTOR inhibition as the rational systemic therapy.

The single-arm phase 2 AMPECT trial tested albumin-bound sirolimus (nab-sirolimus) in advanced malignant PEComa and reported objective responses in around four in ten patients, with responses lasting years in some and higher response rates in TSC2-mutant tumours, leading to FDA approval in November 2021, the first drug approved for PEComa. The PRECISION 1 basket trial extends nab-sirolimus to any solid tumour with inactivating TSC1 or TSC2 alterations.

## Fields

- Kind: Cancer
- Last checked: 2026-09-17
- Also known as: PEComa; Malignant PEComa; Angiomyolipoma and lymphangioleiomyomatosis (PEComa family)
- Tags: subtype-page
- Group: sarcoma
- Burden: A very rare family of tumours, a few hundred malignant cases reported worldwide, arising in the uterus, retroperitoneum, gut and soft tissue of adults, more often women; most are benign, and malignant PEComa was untreatable by chemotherapy until mTOR inhibitors.
- Subtypes: Uterine PEComa (commonest site of malignant PEComa); Retroperitoneal and abdominopelvic PEComa; Gastrointestinal PEComa; Soft tissue and cutaneous PEComa; TFE3-rearranged PEComa (younger patients; not TSC-driven); Angiomyolipoma and lymphangioleiomyomatosis (related, mostly benign)
- Biomarkers: TSC1 or TSC2 inactivation (mTOR inhibitor response); TFE3 fusion (excludes TSC pathway; poor mTOR response); HMB-45, Melan-A and smooth muscle actin co-expression; Size over 5 cm, mitoses, necrosis and infiltration (malignancy criteria)

## Standard of care

- Localised: Complete resection; surveillance for tumours with malignant features; no proven adjuvant therapy. ([Limb-salvage surgery and endoprosthetic reconstruction](https://onco.cc/technologies/limb-salvage-surgery/), [Active surveillance](https://onco.cc/technologies/active-surveillance/))
- Advanced malignant PEComa: Nab-sirolimus (AMPECT; FDA approved 2021); oral sirolimus, everolimus or temsirolimus as alternatives; check TSC status. ([Sirolimus protein-bound particles](https://onco.cc/drugs/sirolimus-albumin-bound/), [AMPECT](https://onco.cc/trials/ampect/), [Everolimus](https://onco.cc/drugs/everolimus/), [Temsirolimus](https://onco.cc/drugs/temsirolimus/), [mTOR](https://onco.cc/targets/mtor/))
- After mTOR inhibitor: Anthracycline- or gemcitabine-based chemotherapy has modest activity; trials of mTOR-based combinations; PRECISION 1 for TSC-altered tumours. ([Doxorubicin](https://onco.cc/drugs/doxorubicin/), [Gemcitabine](https://onco.cc/drugs/gemcitabine/), [Phase 2 Basket Trial of Nab-sirolimus in Patients With Malignant Solid Tumors With Pathogenic Alterations in TSC1/TSC2 Genes (PRECISION 1)](https://onco.cc/trials/nct05103358/))

## State of the art

- Nab-sirolimus is the first approved drug for PEComa, with durable responses in TSC2-mutant tumours.
- TSC1/TSC2 loss defines a targetable pathway across the PEComa family and beyond.
- TFE3-rearranged tumours form a distinct group that needs different treatment.

## Open problems

- Malignancy cannot always be predicted from histology.
- Resistance to mTOR inhibition eventually develops.
- TFE3-rearranged PEComa lacks an effective drug.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Perivascular_epithelioid_cell_tumour
- Wikipedia: https://en.wikipedia.org/wiki/Perivascular_epithelioid_cell_tumour

## Connected records

- cancers: [Retroperitoneal sarcoma](https://onco.cc/cancers/retroperitoneal-sarcoma/), [Sarcomas (soft tissue, bone, GIST)](https://onco.cc/cancers/sarcoma/), [Uterine sarcoma](https://onco.cc/cancers/uterine-sarcoma/)
- targets: [mTOR](https://onco.cc/targets/mtor/)
- trials: [AMPECT](https://onco.cc/trials/ampect/), [Phase 2 Basket Trial of Nab-sirolimus in Patients With Malignant Solid Tumors With Pathogenic Alterations in TSC1/TSC2 Genes (PRECISION 1)](https://onco.cc/trials/nct05103358/)
- drugs: [Doxorubicin](https://onco.cc/drugs/doxorubicin/), [Everolimus](https://onco.cc/drugs/everolimus/), [Gemcitabine](https://onco.cc/drugs/gemcitabine/), [Sirolimus protein-bound particles](https://onco.cc/drugs/sirolimus-albumin-bound/), [Temsirolimus](https://onco.cc/drugs/temsirolimus/)
- technologies: [Active surveillance](https://onco.cc/technologies/active-surveillance/), [Limb-salvage surgery and endoprosthetic reconstruction](https://onco.cc/technologies/limb-salvage-surgery/)

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