Malignant Myopericytoma of Left Supraclavicular Fossa: A Case Report

Introduction: Myopericytoma is a rare soft tissue tumour grouped under perivascular tumours and it is characterized by the circumferential arrangement of perivascular cells around blood vessels. Malignant myopericytoma is an extremely rare occurrence.

Case Presentation: A 44 year old lady presented with a supraclavicular lump for 5 months duration.The lesion was excised and the histology revealed an unencapsulated lesion with perivascular arrangement of spindle cells with nuclear pleomorphism and high Ki-67 index suggestive of a malignant myopericytoma.

Discussion: Myopericytomas are benign tumours that occur in skin and subcutaneous layers of the extremities in middle-aged patients. Myopericytomas are often diagnosed following excision as there is no pathognomonic radiological features. These are unencapsulated lesions and consist of concentric oval to spindle shaped cells that characteristically grow around blood vessels in an “onion skin” pattern. Immunohistochemical staining is positive for Alpha smooth muscle actin (ASMA) and H caldesmon. The malignant potential is identified from high cellularity, the number of mitoses, nuclear atypia, Ki 67 value.

Conclusion: Due to its rarity, myopericytomas impose diagnostic difficulties and it should be considered in the differential diagnosis of hypervascular lumps in the neck. Malignant myopericytomas are aggressive and surgical excision with a wide margin is the treatment of choice.