Bullae are simply large vesicles. They may arise from cleft formation in or below the epidermis, or following coalescence of adjacent foci of intercellular epidermal edema. Comedone P,S Dilated hair follicle containing a pigmented impaction of lipid and keratinaceous debris (a "blackhead). Often seen in keratinization defects; can be seen with demodicosis, and are a frequent finding on the abdomen of dogs with hyperadrenocorticism.

blisters beneath or within the epidermis

A large blister.

intrapulmonary structures usually attributed to excessive rupture of alveolar walls. They appear to affect upper and lower lobes equally and may develop in the absence of generalized emphysema. Their walls are composed of compressed parenchymal tissue and strands of emphysematous lung.

Large cyst-type structures in the Lungs.

Large, bubble-like spaces where lung tissue has been destroyed. These large spaces compress normal lung tissue.

In nematodes: Blisterlike prominences near the vulval fenestra of some Heteroderidae. ( 14)

substructure

structure