Pseudomyogenic hemangioendothelioma

Pseudomyogenic
hemangioendothelioma/epithelioid sarcoma-like hemangioendothelioma of the lower limb: report of a rare case. The imaging (MRI) of the tumor. MRI shows multiple subcutaneous nodules at the left calf below the knee integrating to a mass about 6 cm × 5 cm. The biggest one was about 1.4 cm × 0.9 cm. (a, T1-weighted image shows low signal intensity, ; b, T2-weighted image (STIR) shows high signal intensity, ). MRI also detected a subcutaneous mass about 3.2 cm × 3.4 cm at the left thigh near the inguinal area (c, T1-weighted image shows low signal intensity, ; d, T2-weighted image (STIR) shows high signal intensity, )
diagnosticpathology.biomedcentral.com • CC-by-4.0
Cytotoxic and
targeted therapy for treatment of pseudomyogenic hemangioendothelioma. Imaging studies for 45-year-old patient (“Case 1”) with pseudomyogenic hemangioendothelioma. a Baseline fat saturated T1-weighted axial magnetic resonance image with intravenous contrast enhancement of the pelvis demonstrates multiple enhancing tumor foci in the right iliac bone (white arrow). b Positron emission tomography-computed tomography (PET-CT) fusion image through the pelvis demonstrates diffuse metabolic activity in the right anterior iliac bone (disease in the right posterior iliac bone at the level of the sacroiliac joint was also present but is not shown). This image was obtained 1 month before the patient began gemcitabine/docetaxel. c PET-CT fusion image through the pelvis after three cycles of gemcitabine/docetaxel demonstrates a significant metabolic response
clinicalsarcomaresearch.biomedcentral.com • CC-by-4.0
Cytotoxic and
targeted therapy for treatment of pseudomyogenic hemangioendothelioma. Baseline magnetic resonance imaging (MRI) and positron emission tomography-computed tomography (PET-CT) studies for a 22-year-old man (“Case 2”) with pseudomyogenic hemangioendothelioma. a Baseline contrast-enhanced, fat-saturated T1-weighted axial MR image of the right thigh demonstrates multifocal enhancing lesions in the distal femoral metadiaphysis (short white arrow) and vastus intermedius muscle and subcutaneous fat. b PET-CT fusion image through the distal femurs demonstrates corresponding hypermetabolic activity. Restaging examinations after two cycles of gemcitabine and docetaxel (not shown) did not demonstrate any significant response
clinicalsarcomaresearch.biomedcentral.com • CC-by-4.0
Cytotoxic and
targeted therapy for treatment of pseudomyogenic hemangioendothelioma. Imaging studies obtained during treatment for a 22-year-old man (“Case 2”) with pseudomyogenic hemangioendothelioma. a Fat-saturated T1-weighted axial magnetic resonance image with intravenous contrast enhancement of the pelvis demonstrates a solitary enhancing tumor focus in the supra-acetabular region of the left iliac bone (white arrow), before everolimus treatment. b Positron emission tomography-computed tomography fusion image through the pelvis demonstrates corresponding metabolic activity. This image was obtained before the patient began everolimus treatment. c Fat-saturated T1-weighted axial MR image with intravenous contrast enhancement of the pelvis obtained after 2 months of everolimus demonstrates partial response of the solitary enhancing tumor focus in the supra-acetabular region of the left iliac bone
clinicalsarcomaresearch.biomedcentral.com • CC-by-4.0
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Pseudomyogenic hemangioendotheliomas, also known as epithelioid sarcoma-like hemangioendotheliomas, are locally aggressive and rarely metastasizing vascular neoplasms with histological similarities to myoid tumors and epithelioid sarcomas.

Epidemiology

Pseudomyogenic hemangioendotheliomas are rare and mostly seen in men. They occur in young adults in particular in the 3rd and 4th decade of life. Only about a fifth is seen after the age of 40 years. Approximately 60% of the patients have multifocal disease .

Clinical presentation

About half of the lesions are painful with the other half being indolent and many lesions present as possibly ulcerating cutaneous or subcutaneous nodules. Lesions of the deeper soft tissues and bone might be incidentally detected on imaging .

Pathology

Pseudomyogenic hemangioendotheliomas are often multifocal endothelial proliferations forming multiple separate nodules in distinct tissue planes. It lacks any frank histological vascular differentiation and resembles epithelioid sarcoma or myoid tumors, but expresses vascular features on immunohistochemistry stains .

Etiology

Pseudomyogenic hemangioendotheliomas have an unknown etiology .

Location

Pseudomyogenic hemangioendotheliomas is often multifocal with the involvement of different anatomic tissue planes and body regions. The skin and subcutaneous tissues are affected in three-quarters of the cases. About half of the patients have intramuscular lesions and still a number as high as 20% show an osseous involvement. Lesions are usually found in the lower extremity, whereas the upper limb and trunk are less frequently involved. The head and neck region is a rare site .

Macroscopic appearance

Macroscopically pseudomyogenic hemangioendotheliomas usually appear as smaller nodules rarely being larger than 3 cm with ill-defined borders tannish-grey or white color and a firm consistency .

Microscopic appearance

The histological spectrum of pseudomyogenic hemangioendotheliomas includes the following features :

  • sheet-like or fascicular growth pattern
  • spindle cells and epithelioid cells with eosinophilic cytoplasm
  • no obvious vascular differentiation
  • variable inflammatory infiltrates
  • possible desmoplastic reaction
  • mild nuclear atypia and mitotic activity 
  • rarely pleomorphism
  • infiltration of the surrounding tissues 
Immunohistochemistry

Immunohistochemistry stains are usually positive for keratin, ERG FLI1 and FOSB. CD31 and smooth muscle actin are other markers that be expressed. CD34 is usually negative .

Genetics

FOSB gene rearrangements with a fusion of the SERPINE1-FOSB or ACTB-FOSB have been demonstrated. Both gene fusions show similar clinical and pathological features, although solitary lesions seem to be more common with the ACTB-FOSB gene fusion .

Radiographic features

On imaging pseudomyogenic hemangioendotheliomas usually appear as lobulated and well-defined lesions . Due to the occurrence in different anatomic tissue planes cross-sectional has an important role in the diagnosis and localization of the disease. However, there might be discordant findings across different imaging modalities .

Plain radiograph

Plain radiographs might detect bony involvement as well-demarcated osteolytic lesions involving cortical or cancellous bone or both .

CT

Osseous lesions have been described as expansile osteolytic and well-demarcated without signs of bone destruction or periosteal reaction . Soft tissue lesions might appear as non-specific lobulated well-delineated soft tissue mass.

MRI

MRI imaging has been reported to show expansile well-delineated heterogeneous lesions often multiple .

Signal characteristics
  • T1: low to intermediate signal intensity
  • T2: variably high signal intensity
  • T2FS/STIR: variably high signal intensity 
  • T1 C+ (Gd): homogeneous to a mildly heterogeneous enhancement
Nuclear medicine
PET-CT

PET-CT has been reported to show an intense FDG uptake .

Radiology report

The radiological report should include a description of the following:

  • form, location and size
  • tumor margins
  • relation to the muscular fascia
  • relationship to bones, tendons and joints
  • relationship to local nerves and vessels

Treatment and prognosis

Due to the rare occurrence, optimal management is still somewhat unclear. Treatment usually consists of wide surgical excision possibly with adjunctive chemo- and/or radiotherapy. Local recurrence or appearance of additional nodules is common and occurs in about 60% of patients with a short recurrence time interval of 1-2 years. Lymph node metastases or distant metastases to lungs, bones and soft tissues are infrequent but can occur even decades after the initial presentation .

History and etymology

The tumor was first termed epithelioid sarcoma-like hemangioendothelioma on the first description by SD Billings and colleagues in 2003 and later named pseudomyogenic hemangioendothelioma in 2011 by JL Hornick & CD Fletcher.

Differential diagnosis

The differential diagnosis of pseudomyogenic hemangioendotheliomas also depends on the location of the tumor and consists of the following :