Pseudomyogenic Hemangioendothelioma (PHE)

Pseudomyogenic hemangioendothelioma (PHE), also known as epithelioid sarcoma-like hemangioendothelioma, is a rare type of cancer that develops from epithelial cells in the blood vessels of soft tissues, most commonly the skin of the arms, legs, trunk and head/neck. In rare instances, it can develop in deeper tissues such as muscle and bone. Haemangioendothelioma is a term used to describe neoplasms that act in-between a hemangioma (a benign growth composed of blood vessel cells) and an angiosarcoma (a malignancy found in the lining of blood vessels).

The skin is the largest organ in our bodies that protect us from injury, loss of bodily fluids and help regulate body temperature. There are three layers of the skin: epidermis (top layer), dermis (middle layer) and hypodermis (bottom layer). The epidermis is the water-resistant outer layer of the skin that acts as the body’s first line of defence. It contains squamous cells (upper layer of the epidermis), basal cells (lower layer of epidermis) and melanocytes. The dermis contains the skin’s connective tissues, as well as hair follicles, sweat glands, blood vessels, lymph nodes and nerves. The hypodermis, also known as subcutaneous tissue layer, stores fat (adipose cells), and also contains connective tissue, blood vessels and nerve cells.

PHE is generally more common in men, and tends to be diagnosed between the ages of 30-40. However, anyone can develop this disease.

Treatment

When cancers are detected, they are staged and graded based on size, metastasis, and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you. However, because of how rare PHEs are, there is currently no standard staging and grading system for this disease. Instead of staging and grading, your doctor will recommend a treatment plan based on the following factors:

  • Cancer location.
  • Whether or not the cancer has metastasised.
  • Your age.
  • General health.
  • Your treatment preferences.

Your doctor may also recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.

Treatment options for PHE may include:

  • Surgery to remove as much of the tumour(s) as possible.
  • Chemotherapy.
  • Radiofrequency ablation (RFA).
  • Radiation therapy.
  • Immunotherapy.
  • Clinical trials.
  • Palliative care.

Risk factors

Because of how rare PHE is, there has been limited research done into the risk factors of this disease.

Symptoms

Early-stage PHEs are often asymptomatic, and may be found accidentally during a routine check-up. As the tumour progresses some of the following symptoms may appear:

  • Nodules on the skin (these can be painful or painless).
  • Ulcerating nodules on the skin.

Not everyone with the symptoms above will have cancer, but see your general practitioner (GP) if you are concerned.

Diagnosis

If your doctor suspects you have a HEHE, they may order the following tests to confirm the diagnosis and refer you to a specialist for treatment:

  • Physical examination.
  • Imaging tests, potentially including:
    • CT (computed tomography) scan.
    • MRI (magnetic resonance imaging).
    • X-ray.
  • Blood tests.
  • Biopsy.

References

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