Myopericytoma | Dermatopathology

Myopericytoma is a tumor with perivascular myoid cell differentiation generally presenting as a slowly growing circumscribed and occasionally multinodular dermal or subcutaneous mass of the extremities. The tumor cells assume a spindled appearance and are intimately associated with ectatic branching vessels. They should be completely excised as they have a tendency to recur.

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Slide 1: 52 year-old woman with a 6 month history of a blue nodule on the sole. Low power examination reveals a lesion involving the deeper dermis but is also within the superficial dermis.

Slide 2: The lesion has three main components. The first is in the context of thin-walled vessels. The second is in the context of a myoid cellular component which is found in intimate apposition to the thin-walled vessels. The third is the stroma in which the myoid cells and thin-walled vessels are noted.

Slide 3: The cellularity of the myoid element is greatest in close apposition to the thin-walled vessels but as well these cells extend into the intervening stroma.

Slide 4: The stroma has a hyalinized and myxomatous-like quality. There is no cellular atypia. These are the features of a MYOPERICYTOMA.

Slide 5: Extensive immunoreactivity of the myoid cells for smooth muscle actin.

Slide 6: Extensive immunoreactivity of the myoid cells for smooth muscle actin.