Rhabdomyomatous mesenchymal hamartoma presenting as a sacral skin tag in two neonates with spinal dysraphism

Abstract

Rhabdomyomatous mesenchymal hamartoma (RMH) is a rare congenital malformation involving the dermis and subcutaneous tissue, of which there were 62 reported cases through 2014. We report RMH in two neonates presenting as a sacral skin tag. In both cases, magnetic resonance imaging (MRI) of the spine showed evidence of spinal dysraphism, including a lipomyelomeningocele and a tethered cord. Surgical repair of the defects was performed. Histopathologic examination of the skin tags showed a haphazard arrangement of mature skeletal muscle fibers and adnexal elements, consistent with RMH. The second patient also had a hemangioma on the sacrum and was diagnosed with LUMBAR (lower body hemangioma and other cutaneous defects, urogenital anomalies/ulceration, myelopathy, bony deformities, anorectal/arterial anomalies, and renal anomalies) syndrome, an association between cutaneous infantile hemangiomas of the lower body and regional congenital anomalies. The apparent association of paraspinal RMH with spinal dysraphism suggests that aberrant migration of mesodermally derived tissues (including skeletal muscle fibers) during neural tube development may be responsible for the pathologic findings in the skin. Additional study of patients with spinal dysraphism and congenital cutaneous lesions may further support this hypothesis.

Rhabdomyomatous mesenchymal hamartoma presenting as a skin tag in a newborn

“… 4 , 5 , 6 RMH may be associated with congenital anomalies such as Delleman syndrome, ocular abnormalities, amniotic band syndrome, Goldenhar syndrome, cleft lip or gum, nasofrontal meningocele, and spinal dysraphism. 2 , 3 , 7 Although the etiology of RMH is unknown, possible explanations include aberrant migration of embryonic mesenchymal tissue or abnormal development of mesodermal-derived somite cell populations. 7 …”

“… 2 , 3 , 7 Although the etiology of RMH is unknown, possible explanations include aberrant migration of embryonic mesenchymal tissue or abnormal development of mesodermal-derived somite cell populations. 7 …”

Coccygeal polypoid eccrine nevus associated with imperforate anus and unilateral multicystic kidney dysplasia

“…Pathologically, the polyp is centered by adnexal structures including hair follicles, sebaceous glands and eccrine units, without arrector pili muscle or apocrine structures. Finally, rhabdomyomatous mesenchymal hamartoma, caudal appendage and nevus lipomatosus cutaneous superficialis could also represent differential diagnosis of CPEN and skin tags in sacral areas.…”

Congenital polypoid cutaneous adnexal and mesenchymal hamartoma: an underdiagnosed entity – Report of two cases

“…The fi rst patient presented with a long history of conductive deafness due to congenital agenesis of the stapes. This lesion represents a rare congenital malformation involving the dermis and subcutaneous tissue, with fewer than 70 cases reported to date [ 3 ] . Several cases of SMH have been reported in association with other congenital anomalies, including oculocerebrocutaneous (Delleman) and oculo-auriculo-vertebral (Goldenhar) syndrome [ 6 ] .…”

“…This condition has been described as an isolated event or in association with other head and neck anomalies, including accessory tragus and SMH [ 5 ] . Predilection sites are areas with superfi cial skeletal muscle, such as the nose or chin, followed by the periorbital region and the anterior neck [ 3 ] . This, too, would support the Our cases share similarities with the condition known as striated muscle hamartoma (SMH), which is also referred to as rhabdomyomatous mesenchymal hamartoma and congenital midline hamartoma.…”