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myopericytomatosis

Tuesday 2 January 2018

Myopericytomatosis

Myopericytoma is a benign tumor of concentrically distributed perivascular myoid cells.

Myopericytomatosis affected mostly adults (female:male=8:3; median age, 37 y; range, 9 to 63 y) in the lower extremities (foot/ankle, 5; calf, 3; knee, 1; thigh, 1; neck, 1) over months to 25 years, ranging from 1.5 to 11.0 (median, 6.0) cm in size.

Histologically, myopericytomatosis displayed diffuse infiltration by innumerable discrete myopericytoma/myofibroma-like nodules of bland spindled-to-ovoid cells (smooth muscle actin positive), in a mainly perivascular distribution. No mitoses, atypia, or necrosis was noted.

Myopericytomatosis is a rare, strikingly diffuse, but apparently benign variant of myopericytoma that typically involves superficial soft tissue in adults with innumerable discrete microscopic myopericytomatous nodules.

The strongly activating PDGFRB mutation N666K is noted in myopericytomatosis, but not in conventional myopericytoma, suggesting that PDGFRB mutation status may account for their pathogenetic differences.

As PDGFRB alterations are present in myopericytoma/myopericytomatosis and infantile myofibromatosis/myofibroma, these entities indeed lie within a histogenetic continuum.

Identification of PDGFRB alterations suggests tyrosine kinase inhibition as a potential therapeutic strategy in myopericytic neoplasms if needed.

Molecular biology

Recurrent PDGFRB Alterations in Myopericytomatosis and Myopericytoma

Paywall references

- Myopericytomatosis: Clinicopathologic Analysis of 11 Cases With Molecular Identification of Recurrent PDGFRB Alterations in Myopericytomatosis and Myopericytoma. 2017 doi : 10.1097/PAS.0000000000000862