Neoplasms and the heart - Clinical Tree

KEY POINTS

Cardiac masses are uncommon, mostly encountered as an unexpected finding in clinical practice.
The first step in the differential diagnosis is the question whether this mass could represent a normal variant.
If not, the second step is to consider a vegetation (valvular lesions in particular) or thrombus (anywhere in the heart).
If all of the above are negative, secondary cardiac masses (i.e., metastases) are more common than primary cardiac tumors.
If no metastasis, benign cardiac tumors are more common than primary malignant cardiac tumors, and papillary fibroelastoma and sarcoma are the most common in these two categories, respectively.
Local invasion, evidence of rapid growth, hemorrhagic pericardial effusion, precordial pain, right-sided location and presence of distant metastases are concerning for malignancy.
The clinical context (age, extracardiac symptoms, and comorbidities) helps in providing an initial differential diagnosis; multimodality imaging is key and can be diagnostic, yet pathology, including biopsy, is often needed for the final diagnosis.

Introduction

This chapter will highlight the most common metastatic and primary neoplasms of the heart, accounting for more than 90% of the cardiac tumor practice. Clinical clues to narrowing the differential diagnosis of a cardiac mass include age, location, and syndromic characteristics ( Table 53.1 , Fig. 53.1 ). Important imaging caveats also may be helpful to plan the diagnostic workup ( Table 53.2 ). Echocardiography gives the best temporo-spatial resolution, especially for smaller, intracardiac, and highly mobile masses. Cardiac computed tomography (CT) has advantages over cardiac magnetic resonance imaging (CMR) for more rapid scanning and temporal resolution and, both CMR and cardiac CT are helpful in tissue characterization and evaluation of extracardiac extension of the mass.

TABLE 53.1

Primary Cardiac Neoplasms

	AGE	LOCATION	GENETIC DRIVERS
Benign Neoplasms
Papillary fibroelastoma	Adult	Valves	KRAS
Myxoma	Adult	Atria	PRKAR1A
Rhabdomyoma	Pediatric	Ventricles	TSC1 , TSC2
Fibroma	Pediatric	Ventricles	PTCH1
Lipomatous hypertrophy of atrial septum	Adult	Atria	HMGA2
Lipoma	Adult	Pericardium	HMGA2, TSC1, TSC2
Hemangioma	Adult	Ventricles	—
Germ cell tumor	Pediatric	Pericardium	—
Histiocytoid cardiomyopathy	Pediatric	Ventricles	MT-CYB
Inflammatory myofibroblastic tumor	Pediatric	Ventricles, valves	—
Paraganglioma	Adult	Atria	RET, VHL, SDH
Granular cell tumor	Adult	Ventricles	—
Epithelioid hemangioendothelioma	Adult	Ventricles	WWTR1-CAMTA1
Hamartoma of mature cardiac myocytes	Adult	Ventricles	—
Schwannoma	Adult	Atria	—
Malignant Neoplasms
Undifferentiated pleomorphic sarcoma	Adult	Atria	MDM2
Angiosarcoma	Adult	Atria	Complex cytogenetics
Mesothelioma	Adult	Pericardium	—
Lymphoma	Adult	Pericardium	—
Synovial sarcoma	Adult	Pericardium, valves	SS18-SSX
Rhabdomyosarcoma	Pediatric	Ventricles	—
Liposarcoma	Adult	Ventricles	—
Leiomyosarcoma	Adult	Vasculature	TP53 ^a
Osteosarcoma	Adult	Atria	TP53 ^a
Myxofibrosarcoma	Adult	Atria	TP53 ^a
Solitary fibrous tumor	Adult	Pericardium	STAT6

a Association with Li-Fraumeni syndrome.

FIG. 53.1, Differential diagnoses of cardiac masses by location.

TABLE 53.2

Imaging Characteristics for the Evaluation of Cardiac Tumors

	Echo	CMR	CT
Fat	++	++++	+++
Calcium	+++	+	++++
Thrombus	++	++++	+++
Mobility	++++	++	++
Foreign body	+++	+	+++
Extracardiac extension	+	+++	++++

Malignant neoplasms

Metastatic neoplasms of the heart

Metastatic disease is 20- to 30-fold more common than primary cardiac neoplastic disease and is typically associated with advanced disease; 9.1% of those with metastatic cancer, 14.2% of those with high-grade disease, and up to 18% of those with stage IV disease have metastases to the heart. ^,

Cancers that most frequently metastasize to the heart include breast and lung cancer, melanoma, and hematologic malignancies, such as lymphoma. Cancers that have geographic proximity to the heart tend to metastasize to the heart by direct extension (breast, lung, and thymus). Hematogeneous spread is seen with melanoma and lymphoma, and lymphatic spread with carcinomas. ^, Some tumors may involve the heart by way of venous extension, such as hepatocellular and renal carcinomas, which have ready access to the large systemic veins ( Fig. 53.2 ).

FIG. 53.2, Routes of metastatic involvement of the heart.

Clinically, metastatic disease often manifests as a nonspecific constellation of clinical signs and findings that are dictated by the tumor location and extent of cardiac involvement. Pericardial effusions and clinical tamponade may be the first clinical clues to the presence of pericardial metastases. Over 60% of all cardiac metastases are pericardial in location. The other third of cardiac metastases are myocardial in location and lead to any sinister symptoms, alone or in combination. Arrhythmias, chest pain, and even acute coronary syndrome can be the signs heralding the presence of the metastatic disease. ^, The extent of metastatic burden can be indicative of the consequences; myocardial invasion can lead to loss of contractility and even heart failure. Endocardial burden is rare, and may lead to embolism and possibly obstruction of a chamber or valve.

Primary cardiac malignancies

Primary cardiac neoplasms are rare and much less common than metastatic disease to the heart. Their location makes their treatment problematic; yet, as with most malignancies, early detection is paramount for more successful treatment.

Sarcomas

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