[Perivascular neoplasms of skin and soft tissues. A review]

Perivascular neoplasms of skin and soft tissues comprise a group of benign and malignant mesenchymal neoplasms showing a perivascular myogenic differentiation. Whereas glomus tumour including its variants represents a clearly defined clinicopathological entity, the whole concept of haemangiopericytoma has been questioned in the last years, and no clear diagnostic criteria are established at the moment. Myopericytomas and myofibromas represent a morphological spectrum of perivascular spindle-shaped lesions. Infantile myofibroma/infantile myofibromatosis and solitary myofibroma of adults are characterized by a biphasic growth of mature, spindled, myofibroblastic cells and smaller, immature, mesenchymal cells associated with numerous haemangiopericytoma-like vessels. Benign and rare malignant myopericytomas of skin and soft tissues are characterized by a concentric, perivascular growth of plump spindled and round tumour cells staining positively for muscle actin, alpha-smooth muscle actin and more rarely for desmin. PEComas represent an enigmatic family of neoplasms composed of perivascular epithelioid, clear, and spindled tumour cells characterized by a coexpression of melanocytic and myogenic markers.