Massive low-grade fibromyxoid sarcoma presenting as acute respiratory distress in a 12-year-old girl.

Low-grade fibromyxoid sarcoma (LGFMS) is a rare soft-tissue sarcoma that usually presents in young adults as a painless, slow-growing mass. Evans first described LGFMS in 1987 as a spindle-cell sarcoma with bland histological features and paradoxically aggressive behavior. Although young adults are most frequently affected, recent reports describe pediatric cases being increasingly more common. Males and females are affected approximately equally and common locations include the deep soft tissue of the lower extremity, particularly the thigh and trunk. Primary occurrence within the chest cavity is exceedingly rare. Local recurrence and metastasis are not uncommon and present the clinician and radiologist with challenges regarding follow-up recommendations. Review of the literature reveals many cases of slowly progressive symptoms related to a mass effect. We present a healthy 12-year-old African-American girl who interestingly developed acute symptoms of shortness of breath and chest pain while playing with her brother.

Mesenchymal hamartoma of the liver demonstrating peripheral calcification in a 12-year-old boy.

Mesenchymal hamartoma of the liver is a rare benign hepatic tumor that typically presents in the first 2 years of life. Approximately 85% of affected children present before the age of 3 years and less than 5% present after the age of 5 years. Although spontaneous regression has been reported in this benign tumor, most mesenchymal hamartomas gradually increase in size and can reach enormous proportions. We present an atypical case of mesenchymal hamartoma in a 12-year-old boy. The boy's age and presence of calcifications on CT demonstrate a unique presentation of this rare entity.