Birth-related soft tissue injury due to transverse malpresentation at delivery: a case report

Objectives Birth-related mechanical trauma to the newborn is an important issue and may be underestimated [Chaturvedi A, Chaturvedi A, Stanescu AL, Blickman JG, Meyers SP. Mechanical birth-related trauma to the neonate: an imaging perspective. Insights Imag 2018;9:103-18]. Risk factors for birth-related injuries include vacuum or forceps delivery, large size for gestational age and abnormal presentation before delivery [Gupta R, Cabacungan ET. Neonatal birth trauma: analysis of yearly trends, risk factors, and outcomes. J Pediatr 2021;238:174-80]. When a newborn has a soft tissue mass, there is a wide range of potential diagnoses, ranging from benign traumatic origins to aggressive phenotypes of malignant tumors [Thacker M. Benign soft tissue tumors in children. Orthop Clin N Am 2014;44:433-44]. Diagnosing a congenital tumor in a newborn creates uncertainty for parents and health care providers. Accurate imaging is crucial for distinguishing soft tissue mass origins.Case presentation A 32 weeks 6 days pregnant Caucasian woman was admitted after premature prelabor rupture of membranes (PPROM). Fetal ultrasound showed no abnormalities, the infant was born by a caesarean section. The delivery was complicated by the infant's transverse position. A female infant was born with a large left-sided dorsal soft tissue mass at the thoracic level with elastic consistency, and multiple skin lacerations. A broad differential diagnosis was made. Additional imaging was suggestive for a posttraumatic swelling due to transverse position during birth. The mass decreased and disappeared over three days.Conclusions The diagnosis of a soft tissue mass in a newborn can be challenging. A birth-related trauma affecting the soft tissue should be considered, especially if prenatal ultrasound findings were normal. Malpresentation during birth is a significant risk factor. Accurate diagnostic imaging is important to do before conducting further diagnostic examinations. The time course of the mass, before and after birth, can aid in determining its origin.