Our paper presents a case of primary Kaposi’s sarcoma of the heart in non-immunodeficient
female patient (Table 1). Clinical presentation of pericardial effusion and cardiac tamponade was not indicative
of malignancy. CT coronary angiography and TEE also failed to clarify disease entity.
Such lesions may mimic vegetations and thrombi by their appearance and behavior.
In the available literature, we found 10 confirmed cases of primary Kaposi’s sarcoma
of the heart. Patients’ age varied between 14 to 60 years with mean age of 41.9. 70 %
of patients were more than 38Â years old. Most tumors were localized in the right atrium
4]–8], with two cases (including ours) of right atrial and pericardial involvement 10], one tumor was located in the left atrium 9] and one author described multiple lesions of the heart and pericardium 11]. In most cases tumor arose in the auricle of the right atrium. In these cases disease
was diagnosed either postmortem (due to cardiac rupture) or during imaging procedure
due to heart failure. Clinical presentation was almost similar in all cases.
Rarity of primary KS of the heart is not the only problem during histological evaluation
of the tumor specimens. These lesions contain many necrotic areas, hemorrhages and
thrombi, which complicates the tumor sampling. It is very important to perform a careful
gross pathological examination and dissection (in case of postmortem study) or tumor
tissue sampling (in case of surgical specimen). Pathologists have to promptly examine
all suspicious tissues for histology. As shown by others 11] and in our case, main pathognomonic lesions, which give a clue for differential diagnosis,
are located at the borders of the lesions. In addition, there are other malignant
vascular tumors (spindle cell hemangioma (SCH), angiosarcoma with predominant spindle
cell morphology and Kaposhiform haemangioendothelioma) which clinically and histologically
mimic Kaposi’s sarcoma. As shown by other authors 22], 23] immunohistochemistry cannot clarify the diagnosis, because the molecular features
of these tumors overlap. Although the authors noted 23], that the reactivity of CD34 is stronger in cases of skin Kaposi’s sarcoma in comparison
with a weak and focal reaction in angiosarcomas, in individual cases, like the rare
tumors of the heart, the immunohistochemical investigation cannot discriminate angiosarcoma
from Kaposi’s sarcoma. This method only confirms vascular, endothelial origin of tumor
cells and their proliferative capacity. In these cases, differential diagnosis basically
lay on histological and cytological features of the tumor. Unlike our case, spindle
cell hemangioma contains distinctive epithelioid cells containing vacuoles or intracytoplasmic
lumens. The spindled areas of the SCH contain collapsed vessels, pericytes, and fibroblastic
cells – all the elements of the vessel wall. Kaposhiform haemangioendothelioma was
excluded base on clinical and histopathologic data. It’s occurs nearly exclusively
during the childhood. In addition, our case didn’t contain areas with glomeruloid
nests, epithelioid endothelial cells and hyaline globules, which are distinctive feature
of the kaposhiform haemangioendothelioma. More poorly differentiated vascular tumor,
such as angiosarcoma with predominant spindle cell morphology, exhibits more pleomorphism,
and contains higher number mitotic cells, than Kaposi’s sarcoma.
In some cases, exact type of tumor has no great impact on clinical outcome (lethal
heart tamponade, postmortem diagnosis) but identification of the correct histologic
type of the surgically resected tumor may be meaningful for consideration of adjuvant
chemotherapy 22].