Asymmetry due to anomalous unilateral enlargement of olfactory bulb in Albino rat: A case report

Morphological asymmetry of olfactory bulbs (OBs) primarily based on quantitative estimate of different subcomponents of OBs of right and left side as well as sexual dimorphism is known. Here we report a unique case wherein an otherwise normal female adult albino rat had right-left gross anatomical asymmetry of OBs. Quantitative estimation of its olfactory glomerular subcomponent revealed that the means of glomerular diameter, cross-sectional area and number per 100 sq mm on the left side were 0.50 ±0.04 mm, 0.20 ± 0.03 sq mm, 496 ± 64 respectively as compared to 0.78 ± 0.07 mm, 0.48 ± 0.08 sq mm, and 213.16 ± 41.07 on the right side and the difference observed between two sides of these three comparable parameters were highly significant (p<0.001). Interestingly, all these parameters from apparently smaller looking OB closely matched with similar parameters from control and did not differ significantly. It is concluded that the asymmetry of OBs observed in the present case is due to an unprecedented enlargement of the glomerular subcomponent of the right OB and not due to hypoplasia of left OB warranting further study.