Hemangioendothelioma - mastoid

Case contributed by Mazen Dughly


Palpable mass behind the left ear for further evaluation.

Patient Data

Age: 8 years
Gender: Male

Abnormal space occupying lesion within left mastoid and adjacent part of left temporal bone expending it and protruding within the left middle fossa posteriorly as well as within posterior fossa and causing mass effect upon cerebellum, left sigmoid venous sinus and left temporal lobe.

It showed mixed signal intensity with moderate heterogeneous enhancement mainly in peripheries and likely increase in delayed images.

The right lateral and sigmoid venous sinuses are dominant.

The rest of venous sinuses are dilated. Moderate collateral venous circulation is seen.

Case Discussion

Pathology report:

Gross description: The received specimen is composed of hemorrhagic soft tissue fragments and bone measuring up to ~ 1×1 cm in the aggregates.

Histologic study: The tumor is highly vascularized and shows atypical spindle cell proliferation with irregular vascular formation involving soft tissue and bone. The tumor shows reactive lymphocytic infiltrate with areas of hypercellularity, mitotic activity and focal necrosis 

IHC study:

  • CD31 marker is positive for the tumor cells which determine the endothelial cell origin
  • KI67 marker is generally ~20% with few hot spots with high mitotic activity up to 80%

Conclusion: Scalp, mastoid and soft tissue mass extending the posterior fossa; resection. Low to intermediate-grade blood vascular neoplasm in keeping with hemangioendothelioma (a borderline vascular neoplasm)/low-grade angiosarcoma.

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