Background: Glomus tumor is a soft tissue neoplasm usually observed as a solitary, or sometimes multicentric painful mass, which rarely occurs extracutaneously. We describe this malignant glomangioma of the heart, a first in the Philippine Heart Center, with regard to the clinical presentation, histopathology, and differential diagnosis.
Case: The patient was a 64-year-old male with complaints of right-sided body weakness but without episodes of chest pain, dyspnea, orthopnea, or palpitation. Echocardiography and color flow Doppler revealed a large echogenic mobile structure in the left ventricle and was admitted for surgical intervention. Excision of the mass was done. The procedure was uneventful and patient was eventually discharged improved.
Histopathologic Findings: On gross examination, the specimen consists of several fragmented, tan-brown to gray, irregular, rubbery to friable tissues aggregately measuring 3 x 2 x 1.5 cm. Microscopic sections reveal soft tissue fragments composed of lesional cells in sheets surrounding endothelial cell-lined vascular channels and supported by fibrous stroma. The individual lesional cells exhibit round to ovoid, hyperchromatic to vesicular nuclei, some with prominent nucleoli and lightly eosinophilic cytoplasm. Immunohistochemical studies show the lesional cells with diffuse cytoplasmic reactivity against vimentin, and focal reactivity against smooth muscle actin, S-100, and pancytokeratin (AE1/1). Desmin, calretenin and chromogranin are all negative. The Ki-67 proliferation fraction is between 20-25%. A diagnosis of malignant glomus tumor was made.
Conclusion: Glomus tumor in the heart is extremely rare. This tumor fulfills the criteria for malignancy due to its deep seated location, size (> 2cm) and proliferation fraction of 20%. Clinically, as with any cardiac masses, this may present with a variety of symptoms of cardiac dysfunction, palpitations, dyspnea, angina, cyanosis and may be causes for embolism and stroke. Surgical excision is the treatment of choice in symptomatic cases. These tumors rarely metastasize and generally follow a benign clinical course despite its classification. To the best of the authors' knowledge this is the first case of malignant glomus tumor of the heart in this institution.