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Hemangiopericytoma and Hemangioblastoma
Published in Dongyou Liu, Tumors and Cancers, 2017
Arising from fibroblasts and considered to be within the spectrum of solitary fibrous tumors of the dura, hemangiopericytoma (HPC) may appear as (i) true HPC (including central nervous system [CNS] HPC, spleen HPC, myopericytoma, infantile myofibromatosis, and sinonasal HPC; with clear evidence of myoid or pericyte differentiation); (ii) solitary fibrous tumors, and (iii) non-HPC tumor (e.g., synovial sarcoma, with occasional display of HPC-like features). In the 2016 WHO classification of CNS tumors, true HPC and solitary fibrous tumor (SFT) are restructured as one entity (HPC/SFT) and a grading system is adapted to accommodate this change.
Vascular tumors
Published in Eckart Haneke, Histopathology of the NailOnychopathology, 2017
In general, the histopathologic diagnosis of glomus tumors is obvious. Subungual symplastic glomus tumor exhibits pronounced nuclear pleomorphism, atypia, and multinucleate cells;132 however, no mitoses; it is important to differentiate it from malignant glomus tumor as it has no propensity to metastasize.133 A tumor with a transition of the cuboid glomus cells to more elongated mature smooth muscle cells was termed glomangiomyoma.134 When there is a marked concentric perivascular proliferation of round-to-spindle cells around the glomus cells, the lesion is called glomangiopericytoma.135,136 Glomangioma histologically shows wide vascular lumina that are surrounded by one or several layers of glomus cells (Figure 10.8). One malignant glomus tumor was reported in the hand.137 Epithelioid angioleiomyoma may share some features with glomus tumor and was considered to be an intermediate between angioleiomyoma and glomus tumor.138 Myopericytoma may rarely exhibit areas of glomoid features. However, it was also claimed that myofibromatosis in adults, glomangiopericytoma, and myopericytoma might be a spectrum of tumors with perivascular myoid differentiation.139,140
Orbital myopericytoma: an unusual tumor in an unusual location
Published in Orbit, 2022
Cristina Ye-Zhu, Pablo V. Muñoz-Ramón, Constanza Barrancos, Eugenia Reguero Callejas, Marco Sales-Sanz
Myopericytomas are benign vascular tumors that usually arise in superficial soft tissues of the extremities. Most of the cases reported affect middle-aged male and female patients. Myopericytoma is a tumor with perivascular differentiation, usually composed of oval- or spindle- shaped myoid-appearing cells with eosinophilic cytoplasm growing in a multilayered concentric pattern.1–3Immunohistochemical analysis helps to distinguish myopericytoma from other tumors with similar features, since the tumor cells are positive for smooth muscle actin and occasionally for desmin,1,3 and usually negative for S-100 protein, cytokeratin, and epithelial membrane antigen.4
More to what meets the eyes: Myopericytoma of the preauricular sinus
Published in Acta Oto-Laryngologica Case Reports, 2021
Azlina Ab Rani, Goh Bee See, Nordashima Abdul Shukur, Noor’Ain Mohd Nasir
Preauricular lesions may either be sinuses, cysts or fissures, found lateral and superior to the facial nerve and parotid gland. While some may be asymptomatic for life, recurrent infections may occur in cases where there is presence of bacteria sealed within the tract, the opening of the sinuses or the cyst. Myopericytoma is a benign tumor that is composed of myoid-appearing oval to spindle-shaped cells with a concentric perivascular pattern of growth and is rarely seen in the head and neck region. In this report, we describe a case of myopericytoma occurring in the head and neck skin region with involvement of the preauricular region, where it is known to occur very rarely.
CARMIL2 Immunodeficiency with Epstein Barr Virus Associated Smooth Muscle Tumor (EBV-SMT). Report of a Case with Comprehensive Review of Literature
Published in Fetal and Pediatric Pathology, 2022
Mukul Vij, Meena Sivasankaran, Dhaarani Jayaraman, Srinivas Sankaranarayanan, Vimal Kumar, Deenadayalan Munirathnam, Julius Scott
There are no pathognomonic imaging features for EBV-SMT and biopsy is essential for formal diagnosis. EBV-SMT morphologically resemble leiomyomas or leiomyosarcomas as they are primarily composed of spindle shaped to elongated neoplastic cells with eosinophilic cytoplasm predominately arranged in interlacing fascicles [27]. In some areas neoplastic spindle cells may appear to stream from the walls of irregularly branched blood vessels. These tumors show low mitotic activity, lack necrosis and nuclear atypia is uncommon [28]. Intratumoral lymphocytes, histiocytes and clusters of primitive round cell areas arising gradually or abruptly from the well differentiated spindle shaped cells are the two unique morphological findings described in EBV-SMT [29]. These features may show marked variation in different cases. EBV-SMT in individuals having HIV shows the most diverse morphological variation, ranging from benign looking leiomyoma to leiomyosarcoma-like and even angioleiomyoma or myopericytoma-like features [29]. Immunohistochemistry studies have demonstrated reactivity to vimentin and smooth muscle markers like SMA, caldesmon, muscle-specific actin and desmin. ISH studies have shown patchy to diffuse expression of EBER in these tumors. LMP1 protein expression has also been reported in some tumors. Histologically, the differential diagnosis includes inflammatory myofibroblastic tumors (IMFT), Kaposi sarcoma, mycobacterial spindle cell pseudotumor, myopericytoma and even gastrointestinal stromal tumors (GIST). IMFT may show immunopositivity for ALK1 or ROS1 and molecular studies may further identify ALK1 gene rearrangement or ROS1, NTRK3 and ETV6 gene fusions. Kaposi sarcoma shows immunopositivity for vascular markers CD31 and CD34 and is negative for smooth muscle markers. Myopericytoma is a benign perivascular tumor composed of oval to short fusiform myoid cells arranged concentrically around small vessels. The immunophenotype shows positive staining for smooth muscle markers and is negative for EBER. GIST is positive for CD117 and DOG1 immunostains. Lymphoid proliferations and other round cells like rhabdomyosarcoma may be included in the differential diagnosis if EBV-SMT shows sheets of round cells.