In a few cases, large gemistocytes, neurons, choroid plexus, ependyma, and retinal pigmented cells may be seen. Histochemistry
A trichrome stain will highlight the dual components well, with the glial tissue staining red, while the background fibrosis stains a bright blue. Immunohistochemistry
The glial tissue is highlighted with S100 protein and with glial fibrillary acidic protein, although the latter is much more sensitive for glial tissue. Diagnosis
Differential diagnoses
The most common missed lesion is within the nasal cavity, where a fibrosed nasal polyp may be considered. However, it does not have glial tissue. Further, a polyp usually has mucoserous glands. The lesion is frequently misinterpreted as scar in the subcutaneous tissues, but scar in a < 2-year-old child would be uncommon. Special stains are frequently required to highlight the diagnosis. Imaging findings
Imaging studies are performed before surgery or biopsy to preclude an intracranial connection. Images usually show a sharply circumscribed but expansile mass. It may be difficult to exclude the intracranial connection if the defect is small whether employing computed tomography or magnetic resonance. Classification
While nasal glial heterotopia (NGH) is the preferred term, synonyms have included nasal glioma. However, this term is to be discouraged, as it implies a neoplasm or tumor, which it is not. By definition, nasal glial heterotopia is a specific type of choristoma. It is not a teratoma, however, which is a neoplasm comprising all three germ cell layers (ectoderm, endoderm, mesoderm). As a congenital malformation or ectopia, it is distinctly different from the trauma or iatrogenic development of an encephalocele.
The two, however, are clinically, radiographically, and genetically distinct from one another. Treatment
People with Pyle disease are often asymptomatic. Dental anomalies may require orthodontic interventions. Skeletal anomalies may require orthopedic surgery. Epidemiology
Pyle disease is thought to be a rare disorder, although its prevalence is unknown. More than 25 cases have been described in the medical literature.It has been described in four German families originating from the same town in Bohemia and in a 7-year-old Japanese girl. Research
Cortical-bone fragility is a common feature in osteoporosis that is linked to nonvertebral fractures. Regulation of cortical-bone homeostasis has proved elusive. The study of genetic disorders of the skeleton can yield insights that fuel experimental therapeutic approaches to the treatment of rare disorders and common skeletal ailments. The study showed that Pyle’s disease was caused by a deficiency of sFRP4, that cortical-bone and trabecular-bone homeostasis were governed by different mechanisms, and that sFRP4-mediated cross-regulation between Wnt and BMP signaling was critical for achieving proper cortical-bone thickness and stability.Recently, homozygous mutations in secreted frizzled-related protein 4 gene (SFRP4) gene were found to underlie this condition. Sequencing of coding regions of SFRP4 gene from an 11-year-old female with PYL was performed. A novel homozygous nonsense variant, c.183C>G (p.Y61*) was observed. Segregation analysis in the patient revealed a germline mutation, resulting in reduced protein formation. References


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