Biparietal osteodystrophy: Macroscopic appearance, computed tomography imaging and microarchitectural analysis

A case of bilateral thinning of the cranial bones in an elderly individual

BACKGROUND

Bilateral thinning of the parietal bone is a condition that has been known since the 18th century, with several names being given since its discovery. The aetiology is unknown but there are numerous theories. Although this condition is rarely encountered, its clinical significance may be relevant to traumatic cases.

OBJECTIVES

This study aims to present a case of bilateral thinning observed in the cranium of an 87-year elderly female, which was assessed macroscopically and radiologically to visualize the exact parameters of the thinned areas to discuss a plausible cause and aetiology of the condition.

METHODS

During maceration for teaching purposes, the cranium was removed and assessed macroscopically. A micro-CT was then taken to determine the exact size and cranial thickness of the lesions.

RESULTS

A differential diagnosis was established which included an unknown aetiology or Gorham-Stout disease. In addition, it was noted that metabolic factors, such as malnutrition and metabolic acidosis, should be considered as factors for increasing its severity.

CONCLUSION

Case studies on the presence of bilateral thinning of the parietal bones has been reported in various countries, while no case studies could be found reporting the presence of bilateral thinning on both the parietal and occipital bones. The combination of thinning reported in this study may suggest increased severity of a more advanced state of the condition.

Traumatic Brain Injury in Patient with Biparietal Thinning

A 77-year-old man presented with progressive consciousness disturbance, presumably caused by a backward fall. Head computed tomography findings showed a large intracerebral hemorrhage in the left parietal lobe. Radiated fractures with an oval depression of the bilateral parietal bone crossing the midline were noted. Surgical evacuation of the hemorrhage was performed via a left-sided parietal craniotomy, during which fragments from the fracture with eggshell-like thinning were noted. Biparietal thinning is an uncommon condition noted in radiological findings of a symmetrical oval depression of bilateral parietal bones with reduced diploe thickness. Cases of traumatic brain injury in patients with biparietal thinning have rarely been reported. This condition should be recognized as a possible predisposing factor for traumatic brain injury.

Long-Term Comparison of Two- and Three-Dimensional Computed Tomography Analyses of Cranial Bone Defects in Severe Parietal Thinning

Parietal thinning was detected in a 72-year-old with recurrent headaches. Quantification of bone loss was performed applying two- and three-dimensional methods using computerized tomographies. Two-dimensional methods provided accurate measurements using single-line analyses of bone thicknesses (2.13 to 1.65 and 1.86 mm on the left and 4.44 to 3.08 and 4.20 mm on the right side), single-point analyses of bone intensities (693 to 375 and 403 on the left and 513 to 393 and 411 Houndsfield Units on the right side) and particle-size analyses of low density areas (16 to 22 and 12 on the left and 18 to 23 and 14 on the right side). Deteriorations between days 0 and 220 followed by bone stability on day 275 were paralleled using the changed volumes of bone defects to 1200 and finally 1133 mm3 on the left side and to 331 and finally 331 mm3 on the right side. Interfolding as measurement of the bones' shape provided changes to -1.23 and -1.72 mm on the left and to -1.42 and -1.30 mm on the right side. These techniques suggest a stabilizing effect of corticosteroids between days 220 and 275. Reconstruction of computerized tomographies appears justified to allow for quantification of bone loss during long-term follow-up.