Large hemangiopericytoma of the shoulder: a case report

Introduction: Hemangiopericytoma is a rare tumor arised from the pericytes, contractile spindle cells that surround the capillaries and post-capillary venules. The tumor was found equally among males and females. Case report: We report a case of a 63-year-old female who presented a giant painful mass on her right shoulder that occurred one year before admission. Limited range of motion and a sense of tingling along the affected arm was present also. An irregular, oval-shaped mass, colored dark-red, with signs of necrosis was the maximal diameter of 14cm. Routine laboratory analyzes showed results within the range of referenced values. Lung X-ray and ultrasonographic examination of the abdomen showed no signs of secondary tumor deposits, and no osteo-muscular lesions in the affected region. Ultrasonographic examination of the neck and right axillary region showed no signs of regional metastases. The surgical excision of the entire tumor was performed, with the associated subcutaneous tissue and a part of fascia underneath. Results of the histopathological analysis confirmed the diagnosis of hemangiopericytoma. The specimen showed no signs or elements of the neoplastic tissue on the edges of the resection lines. 3 years after the operation, there was found no signs of tumor relapses, regional or systemic metastases. Conclusion: Considering that there are no official clinical guides and protocols for hemangiopericytoma management, as well as the occurrence of cutaneous and subcutaneous hemangiopericytomas is exceptionally rare, more extensive research in this field and more described cases are need to gain a better understanding of that issue.


Abstract
Introduction: Hemangiopericytoma is a rare tumor arised from the pericytes, contractile spindle cells that surround the capillaries and post-capillary venules. The tumor was found equally among males and females.
Case report: We report a case of a 63-year-old female who presented a giant painful mass on her right shoulder that occurred one year before admission. Limited range of motion and a sense of tingling along the affected arm was present also. An irregular, oval-shaped mass, colored dark-red, with signs of necrosis was the maximal diameter of 14cm. Routine laboratory analyzes showed results within the range of referenced values. Lung X-ray and ultrasonographic examination of the abdomen showed no signs of secondary tumor deposits, and no osteo-muscular lesions in the affected region. Ultrasonographic examination of the neck and right axillary region showed no signs of regional metastases.
The surgical excision of the entire tumor was performed, with the associated subcutaneous tissue and a part of fascia underneath. Results of the histopathological analysis confirmed the diagnosis of hemangiopericytoma. The specimen showed no signs or elements of the neoplastic tissue on the edges of the resection lines. 3 years after the operation, there was found no signs of tumor relapses, regional or systemic metastases. Conclusion: Considering that there are no official clinical guides and protocols for hemangiopericytoma management, as well as the occurrence of cutaneous and subcutaneous hemangiopericytomas is exceptionally rare, more extensive research in this field and more described cases are need to gain a better understanding of that issue. Hemangiopericytoma is found to appear at any age, but is most common in the sixth and seventh decade 4 . Hemangiopericytoma is primary an adult neoplasm, but occurrence in children is possible also. Considering that, adult and infantile forms of hemangiopericytoma are described in the literature 5 . Some types of hemangiopericytoma (such as glomangiopericytoma) are associated with previous trauma, hypertension, pregnancy or steroid usage but definitive etiology is still insufficiently clarified 6 . The probability of a tumor forming is greater wherever the tissue abounds in capillaries. It has been stated that hemangiopericytoma may occur at any anatomic site and tends to develop from subcutaneous tissue or skeletal muscle. However, in cases reported so far there are areas more affected such as the lower extremities (above the knee) and retroperitoneum 7 , soft tissue of trunk and upper extremities 8 , head and neck 9 , thoracic cavity 10 . In the head and neck region, they are usually seen in the nasal cavity, orbit, jaw, parotid gland, and oral cavity 11 . Hemangiopericytomas also could arise intracranially within the central nervous system (CNS) and account for approximately 0.4% of all CNS tumors 12

Case Report
We present a case of a 63-year old female patient who was referred to the Department of Plastic surgery with a giant painful mass on her right shoulder. The patient was presented with pain, limited range of motion and a sense of tingling along the affected arm, on the initial examination. The tumor was present one year prior to the initial manifestation of the symptoms, when the patient noticed a growth of the neoplasm with occasional bleeding. The neoplasm was described as an irregular, oval-shaped mass, Considering the difficulty to predict biological behavior of this tumor, it is useful to know that the prognostic value includes increased cellularity, anaplasia, necrosis, hemorrhage and prominent mitotic activity detected by microscope, which could be amplified using a proliferation index detected by immunohistochemical techniques. The proliferation index of 10% or greater may indicate a more aggressive type of this rare tumor 15 . The criteria for malignancy proposed by Enzinger and Smith in classical HPC identify overtly malignant or high-grade lesions, but fail to address low-grade lesions 16 . In their study, large-sized tumors (>5cm), increased the mitotic rate, high cellularity, presence of immature and pleomorphic tumor cells, and foci of hemorrhage and necrosis predicted a highly malignant course. Enzinger and Weiss employed the term "low-malignant potential" for lesions with lower levels of mitotic activity, particularly if they have any degree of atypia and cellularity 22 . Metastases were noted in approximately 30% of patients, with a 5-year survival of 71%.
The most common metastatic sites were the lungs, bones and liver 23 . Occurrence of metastases several years after the excision of the primary lesion is a frequent phenomenon regarding hemangiopericytoma and therefore long-term follow-up is essential 24

Conclusion
Early histological diagnosis of hemangiopericytoma is essential and wide surgical excision is recommended. Considering that there are no official clinical guides and protocols for hemangiopericytoma management, more extensive research in the field and more described cases are need to gain a better understanding of the issue. The fact that the occurrence of cutaneous and subcutaneous hemangiopericytomas is exceptionally rare give this particular case report great clinical significance and further our insight in the pathology of this neoplasm. Figure 1. Large, well-circumscribed reddish growth on the right arm skin