Discussion
Our single-center study confirms very good overall accuracy of TTE in CM
diagnosis. This is clinically important as accurate assessment of
cardiac masses is essential for appropriate clinical management and
treatment of these patients.
Diagnosis of CM can be challenging since patients are frequently
asymptomatic or have only non-specific signs and symptoms. Dyspnea, a
frequent and non-specific symptom of cardiac disease, was the most
common complaint in our CM group, which is consistent with previous
reports [9–11]. Clinical presentation itself rarely suggests the
diagnosis of CM; therefore, cardiac imaging is essential in the
evaluation of patients with suspected CM. Echocardiography is the most
widely used imaging modality that provides important information about
the location, size, and appearance of the cardiac mass, as well as
possible complications (e.g. obstruction). Previous studies have shown
that CM are typically solitary, located in the left atrium, smooth in
surface and mobile [12,13]. However, the morphological presentations
of CM are often atypical and heterogeneous, leading to overlap with
other NM cardiac tumors and cardiac masses.
The results of our study show very good overall accuracy (85%) of TTE
in CM diagnosis with excellent sensitivity (97%). However, the
specificity of TTE is modest (50%) and caution is warranted as
misdiagnosis of CM is possible. In our study, 5 of the misdiagnosed
cases of CM were actually papillary fibroelastoma, which is also a
common primary benign cardiac tumor. One of the suspected CM was
actually a metastasis of malignant melanoma, underlying the importance
of surgical excision and pathohistological examination of all suspected
CM.
According to our results tumor localization and tumor size are the best
echocardiographic characteristics to distinguish between CM and NM
cardiac tumors. CM are typically located in the left atrium attached to
the interatrial septum at the region of fossa ovalis, which was also
shown in our study [14]. In our patients, 72% of CM were located
typically. However, all tumors preoperatively misdiagnosed as CM were
located in atypical locations, such as the right atrium and left
ventricle. Tumors in the NM group were also significantly smaller
compared to tumors in the CM group. However, there was no significant
difference in age, sex, and other echocardiographic characteristics
(mobility and surface) between the groups.
The differential diagnosis of CM is broad and definite diagnosis is
crucial, as treatment varies depending on the diagnosis. Multimodality
cardiac imaging improves the diagnostic accuracy of different cardiac
masses. In the majority of our patients, at least one additional imaging
modality was used as a part of the diagnostic workup. TEE improves image
quality and provides more morphological information than TTE [15].
Computed tomography and cardiac magnetic resonance provide additional
information on topographic relationships and tissue characteristics, and
may detect other pathological conditions within the thorax [16,17].
Assessment of cardiac tumors by CMR is more accurate than
echocardiography and can reliably distinguish between benign and
malignant cardiac tumors [18–20].
There are some limitations to this study. First, this is a retrospective
study with a relatively small study population. However, the population
size is comparable to other studies on CM. Due to the low incidence of
cardiac tumors, only multicenter studies can provide a larger scale
patient population. Second, preoperative echocardiography was performed
by different echocardiographers, potentially exposing the results to
inter-investigator variability in determining the diagnosis. Due to the
study inherently including participants already given a working
diagnosis of CM, any cardiologist performing TTE was likely influenced
by the information provided upon referral. A larger, multicenter,
prospective study could serve to identify echocardiographic and clinical
characteristics specific to CM, as well as other cardiac tumors, further
increasing the utility of preoperative diagnostic modalities.