Coexistence of primary hepatic myopericytoma and mediastinal Castleman disease in one patient: an interesting ¹⁸F-FDG PET/CT imaging case

The clinicopathologic features of 24 tumors showing perivascular myoid differentiation are described. These included tumors with histologic features of "infantile-type" myofibromatosis occurring in adult patients (8 cases), tumors with composite features of "hemangiopericytoma" and glomus tumor (9 cases), and tumors with a distinctive concentric perivascular proliferation of spindle cells (7 cases). Evidence of morphologic overlap among these groups suggests they are closely related neoplasms that form a single spectrum. Age of patients with lesions resembling infantile-type myofibromatosis ranged from 23 to 67 years (median, 37 years). Clinicopathologic manifestations of this disease included multicentricity (4 cases), local recurrence (3 cases), persistence of congenital lesions into adulthood (4 cases), and tumors that were multifocal within the confines of one anatomic region (7 cases). Histologically, all cases showed a biphasic pattern that consisted of fascicles of spindle cells with abundant eosinophilic cytoplasm that resembled smooth muscle, in addition to a population of more primitive spindled cells associated with a hemangiopericytomalike vascular pattern. Six cases showed reversal of the typical zonation seen in pediatric cases in that the primitive component surrounded the more mature fascicular areas. Also described are nine tumors with features that are intermediate between glomus tumor and hemangiopericytoma, which we have designated glomangiopericytoma. These tumors are characterized by prominent branching vessels lined by a single row of endothelial cells surrounded by epithelioid cells with a glomoid appearance. In other areas, the tumors showed typical hemangiopericytomatous foci similar to those in the myofibromatosis cases. The principal points of distinction were a lack of myoid nodules and an absence of small primitive cells with basophilic cytoplasm. Ages of these patients ranged from 17 to 78 years (median, 35 years). All tumors were located in the subcutaneous tissue and the superficial soft tissue of the extremities. Recurrence developed in one of six patients with follow-up information. The recurrent tumor had features of angiomatoid malignant fibrous histiocytoma. Finally, we describe a subset of tumors characterized by concentric periluminal proliferation of bland, round to ovoid cells, which we have designated as myopericytoma. Patient age ranged from 10 to 66 years (median, 40 years). All were located in subcutaneous and superficial soft tissue of distal extremities. One patient had two recurrences in 3 years after initial excision. Our study suggests that these three lesional groups comprise a histologic continuum of tumors that share clinical similarities and that, perhaps, are designated more appropriately as perivascular myomas. The relationship of this family of tumors to so-called hemangiopericytoma is discussed. Show more

Perivascular neoplasms comprise traditionally glomus tumor and hemangiopericytoma (HPC). Whereas glomus tumor represents a well-defined entity, the existence of HPC as a separate entity has been questioned because a number of neoplasms of different lines of differentiation are characterized by a HPC-like vascular growth pattern. Myopericytoma represents a recently delineated entity showing a HPC-like vascular pattern. A large series of myopericytoma of skin and soft tissues has been analyzed to further characterize the clinicopathologic spectrum of this entity. Fifty-four cases of myopericytoma of skin and soft tissues were retrieved and the histology reviewed. Immunohistochemical stainings using alpha-smooth muscle actin (ASMA), desmin, and h-caldesmon antibodies were performed, and clinical data and follow-up information were obtained from referring pathologists. Thirty-four patients were male and 18 were female (gender was unknown in 2 cases). Patient age ranged from 13 to 87 years (median, 52 years). The lower extremities were most commonly affected (26 cases) followed by the upper extremities (16 cases), the head and neck region (4 cases), and the trunk (2 cases); exact location was unknown in 5 cases. In 20 cases, the neoplasms were confined to the dermis, in 6 cases an extension into the subcutis was seen, and 24 as well as 4 cases arose in subcutaneous and deep soft tissue, respectively. Two cases were multicentric; and in 1 of these patients, multiple anatomic regions were involved. Histologically, in all cases, numerous thin-walled vessels and a concentric, perivascular arrangement of ovoid, plump spindled to round myoid tumor cells was seen. However, a broad morphologic spectrum ranging from hypocellular, fibroma-like (3 cases), myofibroma-like (2 cases), angioleiomyoma-like (12 cases), and HPC-like neoplasms (13 cases) to classic myopericytomas (14 cases) and immature, cellular lesions (2 cases) was noted. In addition, 2 neoplasms with focal glomoid features, 5 intravascular, and 1 malignant myopericytomas were found. Prominent cytologic atypia and increased proliferative activity (>3 mitoses/10 high power fields) was seen in 4 and 2 cases, respectively. Immunohistochemically, all cases tested stained positively for ASMA. In addition, 29 of 32 cases tested stained positively for h-caldesmon, whereas desmin was only focally positive in 3 of 33 cases. Follow-up information was available in 46 cases (range, 7-168 months; median, 48 months). Despite marginal or incomplete excision in 23 of 46 cases, only 2 neoplasms (1 malignant and 1 intravascular myopericytoma) recurred locally (within 1 and 4 years, respectively). Despite overlapping morphologic features to angioleiomyoma and myofibroma, myopericytoma represents a distinct perivascular, myoid neoplasm of skin and soft tissues, characterized by a broad morphologic spectrum of concentrically, perivascularly growing myoid tumor cells that stain positively for ASMA and often for h-caldesmon, whereas desmin is usually negative. Most cases of myopericytoma behave in a benign fashion, but local recurrences and rarely metastases may occur in atypical and malignant neoplasms. Show more