Pericytic Lesions: A Paradigm of Overlapping Features

Although myopericytoma and glomangiopericytoma are considered the subtypes of the group myopericytomas (MPC), they differ morphologically. Both of the tumors arise from pericytic cells. Scalp MPC are infrequent, but extranasal glomangiopericytomas are extremely rare. Herein, we report a case of a 36-year-old female presenting with slowly growing scalp swelling. Histopathology showed a dermal tumor with features of myopericytoma as well as glomangiopericytoma within the same lesion. Immunohistochemistry and reticulin staining confirmed pericytic origin but could not differentiate between the two tumors. This case report adds to the rarity and morphologic heterogeneity of the group MPC.

Thoracic myopericytoma in an older adult, rare but possible: A case report

Myopericytoma is a rare tumor generally arising from skin and soft tissues of extremities, trunk, head, and neck regions, rarely from visceral sites. An intrathoracic visceral localization may carry a broad differential diagnosis including primary lung, pleura and chest wall lesions, or metastatic lesions. To date, any radiological features have been recognized and diagnosis of myopericytoma with intrathoracic localization remains still challenging. Here, we describe the case of a subpleural lesion incidentally diagnosed in an older adult affected by gastric cancer. Radiological features did not allow a differential diagnosis between a benign lesion, a primary tumor, or a metastasis. After resection, the histological examination showed histopathological features congruent with the diagnosis of myopericytoma. This unusual presentation reflects the need to share clinical, radiological, and histopathological data about this uncommon but frequently misdiagnosed disease.

A retroperitoneal myopericytoma: The first case located at the retroperitoneal area and not originate from the kidneys

A 25-year-old woman had a mass of approximately 65 cm × 33 cm × 102 cm, located in the left paraaortic area on CT scan. It was diagnosed as retroperitoneal malignant neoplasm on imaging. Afterward, open retroperitoneal tumor excision was performed. At laparotomy, the mass was carefully dissected from the ureter, renal artery, and aorta and excised as en-bloc. The pathological result was "myopericytoma." Histologically, the pathological findings characterized a pericytic neoplasm characterized by a perivascular growth of myoid tumor cells. In addition, there were uniform, oval-shaped cells with eosinophilic cytoplasm arranged in short fascicles around blood vessels. The cytologic atypia and mitoses were absent. There are many different tumors in the retroperitoneal area. Most of these lesions are malign nature. Nevertheless, for each benign and malign neoplasm, the preoperative imaging method is generally similar. This present case showed the significant findings of myopericytoma, a benign pathology located in the retroperitoneal area.

Renal myopericytoma: A case report and literature review

Renal myopericytoma is an extremely rare entity with just 11 cases reported in the literature. We report the case of a 57 year old Caucasian man who was found to have a renal myopericytoma following nephrectomy for suspected renal cell carcinoma. Renal myopericytoma has a distinct morphological overlap with other pericytic tumours and significant histological variation has been noted between cases reported to date. Further characterising this novel tumour is vital to identify subtypes within this spectrum, understand its behaviour and to identify imaging trends which may lead to pre-operative diagnosis in order to potentially avoid radical treatment.

Novel SRF-ICA1L Fusions in Cellular Myoid Neoplasms With Potential For Malignant Behavior

Pericytic tumors comprise a histologic continuum of neoplasms with perivascular myoid differentiation, which includes glomus tumors, myopericytoma, myofibroma, and angioleiomyoma. Despite their morphologic overlap, recent data suggest a dichotomy in their genetic signatures, including recurrent NOTCH gene fusions in glomus tumors and PDGFRB mutations in myofibromas and myopericytomas. Moreover, SRF-RELA fusions have been described in a subset of cellular variants of myofibroma and myopericytoma showing myogenic differentiation. Triggered by an index case of an unclassified cellular myoid tumor showing a novel SRF-ICA1L fusion we have investigated our files for cases showing similar histology and screened them using a combined approach of targeted RNA sequencing and fluorescence in situ hybridization. A fusion between SRF exon 4 and ICA1L exon 10 or 11 was identified in a total of 4 spindle cell tumors with similar clinicopathologic features. Clinically, the tumors were deep-seated and originated in the trunk or proximal lower extremity of adult patients (age range: 23 to 55 y). Histologically, the tumors were composed of cellular fascicles of monomorphic eosinophilic spindle cells showing increased mitotic activity, harboring densely hyalinized stroma, often with focal areas of necrosis. All 4 tumors had similar immunoprofiles with positivity for smooth muscle actin, calponin, and smooth muscle myosin heavy chain. Tumors were negative for desmin and caldesmon, markers often seen in SRF-RELA-positive tumors with similar morphology. Follow-up information was available in 3 patients. Two patients had no evidence of disease, 2 and 5 years after surgical resection. One patient, a 35-year-old male patient with a 19 cm deep-seated tumor with brisk mitotic activity (>20 mitoses in 10 HPF), developed lung metastases 7 years after initial diagnosis. In summary, we report a series of 4 cellular myoid tumors with novel SRF-ICA1L gene fusions, characterized by bland spindle cell fascicular growth, expression of specific smooth muscle markers, elevated mitotic activity, marked stromal hyalinization, focal coagulative necrosis, and potential for malignant behavior. Given the morphologic overlap with related cellular myopericytic tumors with SRF-RELA fusions, it is likely that SRF-ICA1L fusions define a similar subset of neoplasms composed of immature smooth muscle cells.

Mesenchymal Neoplasms of the Genitourinary System: A Selected Review with Recent Advances in Clinical, Diagnostic, and Molecular Findings

Mesenchymal neoplasms of the genitourinary (GU) tract often pose considerable diagnostic challenges due to their wide morphologic spectrum, relative rarity, and unexpected incidence at GU sites. Soft tissue tumors arise throughout the GU tract, whether from adventitia surrounding or connective tissues within the kidneys, urinary bladder, and male and female genital organs. This selected article focuses on a subset of these lesions, ranging from benign to malignant and encompassing a range of patterns of mesenchymal differentiation, where recent scholarship has lent greater insight into their clinical, molecular, or diagnostic features.

[Renal angioleiomyoma with a myogenic and melanocytic immunophenotype, as a variant of angiomyolipoma]

We present a case of a 67 year old male with a cortical nodular tumour of the left kidney. During a year's follow-up with ultrasound and MRI, the tumour was seen to increase in size by 16-20 mm. The nodule was surgically removed. Microscopically it was well defined and unencapsulated, with a proliferation of typical fusiform cells of smooth muscle cell appearance, clumped around well vascularized areas. Immunohistochemically, the neoplasm was positive for muscle markers (smooth muscle actin, desmin and caldesmon) and melanocyte markers (HMB-45 and Melan A). Our case would appear to be a renal neoplasm with an angioleiomyomatous pattern, but with immunohistochemical characteristics of angiomyolipoma (PEComa), however, without either a lipomatous or lipid cell component. We found no previous reports of this type of tumour in the literature.

Foot soft tissue myopericytoma: Case-report and review

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Myopericytoma is a rare tumor of deep soft tissues.

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Small tumefying at the level of the plantar region, between the 2nd and 3rd toe of the right foot.

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Neoformation of 0.6 cm in diameter, well circumscribed, capsulated and with free resection margins.

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The immunohistochemical profile was consistent for positive alpha-actin and negative desmine.

Introduction

Myopericytoma is a rare tumor of deep soft tissues, originating from pericytes and characterized by numerous thin walled blood vessels.

Case report

We report a case of myopericytoma found at the level of the second toe of the right foot.

A patient came to the Endocrinology Surgery Department of Catania Polyclinic because of a presence of a small swelling in the plantar region, between the 2nd and 3rd toe of the right foot. At the anatomopathological examination, the escalated lesion showed a neoformation of 0.6 cm in diameter, well circumscribed, capsulated, with myopericytoma diagnosis.

Discussion

Its histopathological appearance is similar to myofibromatic lesions from glomic and angiomyoma tumors. It is a rare tumor that affects all ages with a peak after 50 years 3. The most frequent localization is at the lower extremities, particularly in soft subcutaneous tissues, but can rarely occur in other sites.

Conclusion

At the anatomopathological evaluation, the immunohistochemical examination for the correct formulation of the diagnosis is essential and an adequate surgical excision is important.

Case Report: A giant myopericytoma involving the occipital region of the scalp - a rare entity

Herein we report a rare case of a giant myopericytoma presenting in a 16-year-old girl as a slowly progressive swelling involving the scalp in the occipital region. It was managed by complete excision. Histological examination of the lesion revealed  spindle-shaped cells forming characteristic rosettes around the blood vessels, and positive staining with smooth muscle actin.

Myopericytoma in urinary bladder: a case report

BACKGROUND

Myopericytoma is reported to occur mainly in the skin and superficial soft tissue of the extremities. In contrast, occurrence in the urinary bladder is extremely rare.

CASE PRESENTATION

We describe a 75-year-old Japanese man who developed a submucosal tumor at the right trigone of his bladder that led to interference with the discharge of right ureteral calculus. No invasive growth was observed by magnetic resonance imaging. Transurethral resection was successfully performed; histopathological analysis revealed perivascular proliferation of spindle-shaped to oval-shaped, cytologically bland tumor cells with eosinophilic cytoplasm. On immunohistochemical examination, the tumor cells were positive for alpha-smooth muscle actin, desmin, CD34 and h-caldesmon.

CONCLUSION

Cystoscopic and pathological findings were compatible with a diagnosis of myopericytoma of the urinary bladder.

Myopericytoma of the distal forearm: a case report

Myopericytoma is a rare type of soft tissue tumor with perivascular myoid differentiation. Although the pathology characteristics of myopericytomas are well described in literature, the clinical characteristics of these tumors have received less attention. We report on a 44-year-old female who developed a myopericytoma in her right distal forearm. The patient presented with a painless solid mass that had been slowly increasing in size for approximately 5 years. Unlike typical myopericytoma in the extremity growing as a subcutaneous nodule, the tumor enveloped the distal ulna. This case suggests a different growth pattern for myopericytoma. Myopericytoma is a rare soft tissue tumor originating from perivascular myoid cells, which has only been recognized as a distinct condition in the past 15 years (Granter et al. Am J Surg Pathol. 22 (5):513-25, 1998). Most of these tumors present as a painless, slow-growing subcutaneous nodule. They have typically been described by pathologists who concentrate on the pathological features rather than the clinical characteristics of these tumors (Granter et al. Am J Surg Pathol. 22 (5):513-25, 1998; Dray et al. J Clin Pathol. 59 (1):67-73, 2006; Mentzel et al. Am J Surg Pathol. 30 (1):104-113 2006). We report a case of myopericytoma with an unusual growth pattern involving the distal forearm to highlight the clinicopathologic features of this tumor.

Benign perivascular myoid cell tumor (myopericytoma) of the urinary tract: a report of 2 cases with an emphasis on differential diagnosis

Myopericytoma is a benign mesenchymal neoplasm thought to comprise part of a spectrum of perivascular myoid cell neoplasms with myofibroma, angioleiomyoma, and glomus tumor. We describe 2 such neoplasms involving the urinary tract: 1 incidentally identified in the kidney of a 59-year-old woman and 1 in the urinary bladder of a 52-year-old woman who presented with urinary frequency and dysuria. Histologically, the bladder tumor was composed of numerous blood vessels surrounded by plump perivascular myoid cells, as in subcutaneous myopericytoma. The renal tumor showed similar morphology centrally and a symplastic glomus tumor-like growth pattern at the periphery. Immunohistochemically, both tumors were reactive for markers of smooth muscle differentiation, such as smooth muscle actin and caldesmon/calponin but negative for CD34, cathepsin K, and S100 protein. Both patients are free of disease 14 and 39 months after resection, respectively. Our findings broaden the morphologic spectrum of myopericytoma.