Lateral meningocele with asymmetric canal stenosis: A case study

A case of pancreatic pseudocyst as a rare cause of a cystic lesion within the psoas muscle

Acute pancreatitis is highly prevalent in Australia (Nesvaderani et al. Acute pancreatitis: update on management. Med J Aust 2015;202:420–3). Pancreatic pseudocysts, although typically occurring in the peripancreatic tissues, can in up to 25% be extra-pancreatic (Rasch et al. Management of pancreatic pseudocysts—a retrospective analysis. PLoS One 2017;12:e0184374). Extension of pseudocysts into the psoas muscle is highly unusual, with only 13 previously recorded cases (Gupta et al. Retroperitoneal cystic malignant fibromas mimicking a psoas abscess. Iran J Radiol 2015;12:e17507). This article presents the case of a 45-year-old man presenting with progressive left hip pain. He was known to have a history of chronic alcohol misuse. He presented with symptoms and signs typical of psoas pathology and was found to have a large pancreatic pseudocyst extending into his left psoas muscle. In this case, management was via both computed tomography guided percutaneous drainage and endoscopic ultrasound guided drainage. Because of the rarity of psoas pseudocysts and their propensity to mimic other pathology, diagnosis can be extremely challenging. Cystic lesions within the psoas muscle have several differentials, ranging from the more common psoas abscess to extremely rare neoplastic lesions.

The Skeleton of Lateral Meningocele Syndrome

Notch (Notch1 through 4) are transmembrane receptors that determine cell differentiation and function, and are activated following interactions with ligands of the Jagged and Delta-like families. Notch has been established as a signaling pathway that plays a critical role in the differentiation and function of cells of the osteoblast and osteoclast lineages as well as in skeletal development and bone remodeling. Pathogenic variants of Notch receptors and their ligands are associated with a variety of genetic disorders presenting with significant craniofacial and skeletal manifestations. Lateral Meningocele Syndrome (LMS) is a rare genetic disorder characterized by neurological manifestations, meningoceles, skeletal developmental abnormalities and bone loss. LMS is associated with NOTCH3 gain-of-function pathogenic variants. Experimental mouse models of LMS revealed that the bone loss is secondary to increased osteoclastogenesis due to enhanced expression of receptor activator of nuclear factor kappa B ligand by cells of the osteoblast lineage. There are no effective therapies for LMS. Antisense oligonucleotides targeting Notch3 and antibodies that prevent the activation of NOTCH3 are being tested in preclinical models of the disease. In conclusion, LMS is a serious genetic disorder associated with NOTCH3 pathogenic variants. Novel experimental models have offered insight on mechanisms responsible and ways to correct the disease.