Clinically malignant atypical glomus tumour

Abstract

Glomus tumours (GTs) resemble the normal glomus body and have a predilection for skin and subcutaneous tissue. Although the majority of glomus tumours are small, benign neoplasms that occur in the dermis or subcutis of the extremities and cases of atypical or malignant variants have been reported. We report a case of a man who presented with a 1-year history of subcutaneous nodule in the right scapular area which was mildly tender. The nodule measured 2 cm. Microscopic examination showed features of glomus tumour with increased mitotic activity. These features, by current definition, would suggest glomus tumour of uncertain malignant potential. Three months later, he presented with recurrence. During his metastasis work-up, we noticed bilateral pulmonary metastasis. Metastasising GTs are rare. The patient underwent wide local excision and received chemotherapy.

Glomangiosarcoma Arising from a Prior Biopsy Site

“… 4 Based on these findings, the following diagnostic criteria for malignancy have been established: size greater than 2 cm, subfascial location, atypical mitotic figures, moderate to high nuclear grade, and 5 or more mitotic figures per 50 high powered fields. 1 , 4 …”

“…In the skin and soft tissue, these lesions must be differentiated from other cutaneous round cell tumors such as Merkel cell carcinoma, eccrine spiradenoma, and melanoma as well as leiomyosarcoma and hemangiopericytoma. 1 , 3 Histologically, glomangiosarcomas have sheets of uniform, round to oval cells with eosinophilic cytoplasm, numerous vascular spaces, and cellular pleomorphism associated with frequent mitotic figures, features not present in benign glomus tumors. 4 , 5 On immunohistologic staining, glomangiosarcomas express many of the same antigens as their benign counterparts, including positive staining for vimentin, smooth muscle actin, and muscle-specific actin.…”

“… 4 Despite this seemingly dismal prognosis, local recurrence with simultaneous bilateral pulmonary metastases has been successfully treated with re-excision and platinum-based chemotherapy in 1 previous case. 1 …”

“…In rare circumstances, glomus tumors may show unusual clinical features such as large size, multicentricity, deep soft tissue infiltration, or extradermal origin. 1 …”

Glomus tumour of the elbow: a case of mistaken identity

“…An exceptionally rare phenomenon, malignant transformation after recurrence or dedifferentiation of a benign glomus tumor, has been described [1,9]. Studies have described metastasis to regional lymph nodes and lungs [10,11].…”