Serious Renal Hemorrhage in Masson Tumor

A RARE CASE OF MEDIASTINAL MASSON'S TUMOR MIMICKING A THYMOMA

Masson's tumor or intravascular papillary endothelial hyperplasia (IPEH) is a rare non-malignant pseudotumoral disease, arising in different anatomic sites, that can clinically and radiologically mimic various benign and malignant tumors. We report the first case in the literature of a mediastinal Masson's tumor, mimicking a thymoma, in a 48-year old man, successfully treated with surgery. Though surgical removal may be technically difficult due to the intrinsic hypervascularized nature of these pseudotumoral benign lesions, resection is generally recommended as they represent a locus minoris resistentiae of blood vessels, potentially causing fatal bleedings.

Masson's tumor of the kidney: a case report

BACKGROUND

Intravascular papillary endothelial hyperplasia (known also as Masson's tumor) is a benign vascular lesion that commonly occurs in the skin and is rarely found in solid organs, especially in the kidney. In what follows, we will look into the first case of an unexpectedly diagnosed Masson's tumor of the kidney presenting as a suspicious renal cyst.

CASE PRESENTATION

A 61-year-old Arab man presented with a left renal cyst, incidentally revealed by ultrasonography. The laboratory values were unremarkable. Computed tomography and magnetic resonance imaging demonstrated a 38 mm left renal midportion Bosniak IV cyst. Our patient underwent a radical nephrectomy. Histopathology revealed the diagnosis of intravascular papillary endothelial hyperplasia. There was no recurrence detected after 9 years of follow-up.

CONCLUSIONS

Renal intravascular papillary endothelial hyperplasia is a rare benign tumor which can mimic a suspicious renal mass on radiological findings. Thus, this entity should be considered more often in the thick of the diagnostic possibilities in order to avoid unnecessary nephrectomies.

Sonographic features of intravascular papillary endothelial hyperplasia (Masson's tumor) in the forearm

Intravascular papillary endothelial hyperplasia, also known as Masson's tumor, is a benign, vascular lesion in which there is papillary proliferation of endothelial cells. The lesion presents as a palpable soft-tissue mass, often located within normal or dilated vascular spaces, and may be mistaken for a sarcomatous tumor on imaging. We present the case of an intravascular papillary endothelial hyperplasia in the forearm, with a remarkable appearance on color Doppler sonography, and suggest that this entity will be encountered more frequently by sonologists in the future.