{'fraction_non_alphanumeric': 0.021300448430493273, 'fraction_numerical': 0.002802690582959641, 'mean_word_length': 5.329787234042553, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Spontaneous resolution of obstructive valvular tumors in infants.

BACKGROUND
Myxomas, the most common cardiac tumor in adults, occur in the atria and are prone to embolization. Obstructive valvular tumors in infants occur in pulmonic and aortic valves and generally have a more benign course.


METHODS
We conducted a review of our experience in infants with tumors obstructing the right or left ventricular outflow tract, originating from pulmonic or aortic valve tissue. Tissue diagnosis was available from only the index case; 4 additional infants survived with spontaneous regression, and only echocardiographic characterizations were available.


RESULTS
Five cases were found with obstructing valvular tumors. In the index case, the obstruction resulted in heart failure, required surgical extirpation, and revealed histology diagnostic of a myxoma. In the subsequent 4 infants with conditions diagnosed with echocardiography, the appearance was suggestive of myxomas (small, compact, ovoid, with no fronds and no embolization). All 4 cases remained mildly to moderately obstructive and then showed spontaneous regression during a period of months to years.


CONCLUSION
None of our cases deteriorated clinically, except the first, and were therefore different from other tumors, such as adult atrial myxomas, papillary fibroelastomas, fibromas, and rhabdomyomas. Only the latter are known to spontaneously regress in infancy. The prevalence of valvular tumors in infants may have previously been underestimated, given the absence of symptoms in 4 of our cases and the spontaneous regression of the tumor. An alternate diagnosis for these 4 cases could be a tissue "myxomatous rest" as opposed to a neoplastic myxoma. In either case, surgical intervention may not be necessary.